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S. NO. CHAPTER PAGE NO.

1.

INTRODUCTION TO SBA

2

2.

DO AWAY CONVENTIONAL EARTHING

SWITCH TO CHEMICAL PIPE EARTHING! WHY?

3

3.

EFFICIENCY AND LONG LIFE OF CHEMICAL

EARTHING

6

4.

Earthing in Rocky/Hilly Areas .. How &

Why ?

9

5.

INSTALL CHEMICAL EARTHING. HOW?

13

6.

SYSTEMS OF GRID EARTHING

Why & How ?

17

7.

PARAMETERS OF GOOD EARTHING.

What Are These?

22

8.

select size number of earthing for an

Industry. HOW ?

24

9.

Why Accept GI Electrode Vs Copper?

26

10.

Technical Specifications

28

11.

Eletricity is Polluted Today ! Why ?

29

12.

Problem of Floating Neutral

Voltages. HOW & WHY ?

32

13.

Floating (NE) Neutral to Earth

Voltages–Causes and Remedies

35

14.

WARRANTY FOR THREE YEARS

39

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INTRODUCTION TO SBA

We are an established unit at NOIDA ,manufacturing the Chemical Earthing Electrodes , the

modern concept of electrical earthing systems , now widely accepted and used by the electrical

consultants , project engineers and electrical contractors, in Industrial,Commercial and

Multistory Apartments for providing safety to persons from electric shocks and prevention of

electrical Fires & hazards including malfunctioning of electronic and electrical equipments due

to ineffective earthing . The Chemical Earthing Electrodes manufactured by us are totally

maintenance free and have estimated life fifteen years.The electrodes manufactured by us are

unconditionally guaranteed for three years from date of installation.

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DO AWAY CONVENTIONAL EARTHING SWITCH TO

CHEMICAL PIPE EARTHING! WHY?

The conventional earthing is out of date because:

1. The water level is going down at most of the geographical areas & therefore one has to dig

deep holes may be to the extent of 20-50 mtr.

2. The commonly used substances in pit type earthing were sodium Chloride known as common

salt, soft coke & charcoal.

3. The common salt (sodium chloride) is a hygroscopic substance & it gets dissolved in water &

losses its hygroscopic properties when become water itself.

4. The salt is known to be a corrosive electrolyte which decays the pipe and the conductor used

for earthing. Due to decay one does not get the consistent ohmic values.

5. The soft coke & charcoal tend to become ash due to heavy heat generated by heavy electric

fault currents generated in the system especially at higher voltages at 1.1kv, 3.3kv, 6.6kv, 11kv,

33kv, 66kv &133kv transmission distribution line & at substation.

6. The heat generated is proportional to I2Rt (Time in seconds) e.g. if the fault current of

10,000amps in the system with an earth resistance 2 ohms as permitted by IS in 0.1 seconds is

given as under.

H=I2Rt

H=10,000x10, 000x2x0.01=20, 00,000 calories =1053 °C

This much heat generated in one fault. Assuming 6 faults in a year. Then in a period of four year

-24 fault occur , each fault generating 1053 °C & Above.

7. Each fault of this magnitude will turn the soft coke/ charcoal into ash gradually in a period of

3-4 years. The earth system will deteriorate and give larger value of ohmic resistance thereby

endangering the entire installation consequently people & property.

8. If the ohmic values goes up from 2 to 3 ohms because of faulty earth systems heat generated

will be 30,00,000 calories (i.e. 1600 °C )this results that the pit type earthing is inefficient , not

reliable & cause serious damage to life & property in a period of 3-4 years .

9. It is therefore observed that separate watering arrangement required to be made for

maintaining moisture through a separate pipe dug along the earthing system.

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10. Instead of water producing the moisture in the earth pit the additional quantity of water

poured in with a natural rain fall will wash away the charcoal & the soft coke from its main

position thereby it will further deteriorate the functioning of the earth system.

Why install chemical earthing:

The above points conclude that pit type earthing is out of date and it is being replaced and

preferred over chemical pipe earthing for reasons given below:

1. The pipe for the chemical earthing are generally 2 mtr or 3mtr in length therefore the earth

bore need not more than the 200 to 250mm dia & maximum depth of 3mtr.

2. The moisture is maintained at a small depth of 3mtr by using ground enhancement material,

commonly known as GCM (GROUND CONDUCIVE MATERIAL).

3. The efficacy of the chemical earthing to maintain the moisture which is essential for low

ohmic values of earthing resistance is due to use of hygroscopic chemical like aluminum silicate

etc. which absorb the moisture but doesn’t get dissolved in the water unlike salt.

4. The heat generated due to electric faults developing heat of 1060 °C and above is resisted by

CCM (Crystalline Conducive Material) which can withstand upto 2500°C.

5. The CCM is filled in the pipe of appropriate dimension of 50mm or 80mm dia and sealed at

both ends. It incorporates the earth conductor of GI strip of suitable size of 25x6mm or 50x6mm

depending upon the individual design of manufacturer.

6. The CCM filled in the pipe being a good conductor increases the fault current capacity of the

system because the pipe is hollow but when filled with CCM it behaves like almost solid pipe.

7. The CCM resists cracking, warping, shrinking, or distortion even when temperature exceed

2500 °C due to severe repeated electric faults which may happen in operations over the year.

8. The GI pipe used are adequately galvanized (80-100 microns) as per IS -3047 1987.

9. Zinc oxide will be formed during the use of the earth system. Zinc oxide has following

advantages over the conventional earthing which uses the copper plate or copper conductors:

a) Zinc oxide so formed is insoluble in water.

b) Zinc oxide has a unique Dielectric strength that exhibits semiconducting & piezoelectric dual

properties. (Unlike in copper where the copper oxide is a bad conductor of electricity & becomes

powdered Red Oxide (Copper Oxide) under high fault current that generate high temperatures)

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c) ZnO finds application in Varistors which are used to prevent voltage surges in the electronic

devices like mobile phone.

d) ZnO is not combustible & used as a fire extinguishing material.

CONCLUSION:

The industry, project managers & the electrical consultants find it very convincing to use &

specify the chemical pipe earthing which is convenient to install, no maintenance what so ever

with a long life of over 15 years.

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EFFICIENCY AND LONG LIFE OF CHEMICAL EARTHING –

HOW?

1. Life of earthing Electrodes:-

1. The conventional copper pit type earthing has a very erratic behavior and the ohmic values of

earth resistance vary drastically on the following seasonal factor:

a) SUMMER SEASON:-

b) WINTER SEASON:-

c) RAINY SEASON:-

The humidity factors in all the seasons vary because ambient temperature of ground varies. The

thumb rule for calculating humidity at a 20°c ambient temperature and 1° variation in either side

(+/-) will vary the humidity level in the ground by 16%. You can now understand why the ohmic

values remain erratic during the life of the system.

There is a general accepted fact and practice that pit type earthing is watered through an

additional pipe running through the depth of pit in summer season obviously because of dry

climate and low humidity.

Contrary to the belief that winter is a wet climate and has a higher humidity level it is a myth and

humidity is very low in winter because the ambient temperature is in the vicinity of 4 to 6°c and

as per the formula given in the paragraph one the humidity is reduce by 16% of every degree of

temperature. The humidity is reduced by 16x (20-6) =224%. This open secrete and it can be very

frank to the newspaper report under the heading “Today’s Weather”.

The coal used in the earthing pit burns and turns into ash under high level of fault currents and

on the top of it the quality of coke is used is very poor(Generally in Powder form).

The salt used becomes water itself and looses its hygroscopic properties.

Conclusion: The life of pit type of earthing is not more then 3 years irrespective of maintenance.

Chemical Pipe earthing:-

In the above type of earthing the following important factor are taking into the consideration:

a) The hollow pipe used in the chemical pipe earthing is fitted with a G.I. strip 40x6mm and

CCM (Crystalline conducive mixture) is compressed in to the pipe and pipe is sealed at both the

end.

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b) CCM is a semi metal and the hollow pipe filled with CCM behave like a salt pipe and

therefore the current carrying capacity increases substantially.

c) The CCM has a high melting temperature of 2500°c and unlike coal it will not burn into ashes

under high temperatures of 1500°c under high fault currents occurring due to phase to phase or

phase to earth fault.

d) The humidity factor (The moisture level) is maintained by Bentonite surrounding the electrode

in a slurry form. The Bentonite has a property of absorbing water 15 times its weight and doesn’t

dissolve in the water. It remains moist and soft through out the life. A minimum rain fall of 2.5

cm in a year makes the Bentonite moist and humid for next one year and therefore the cycle

keeps on repeating year of year. Therefore, because of quality of Bentonite no additional

watering is done whether in summer, winter or rainy season i.e. under any climatic condition.

Conclusion:- The life of chemical earthing as per the reports from USA and other country is

more than 15 years with no failure records. Some company in USA guarantee life of 30 year or

may be above. They are fearing that metal may erode due to chloride and oxides are formed due

to under ground chemicals.

e) In India the technology is only 11 years old and the failure record is almost negligible. The

earthing system properly installed under the guidance of manufacturers can safely vouch for

minimum ten years.

2. GRAPHICAL REPRESENTATION:-

PIT TYPE EARTHING:-

The conventional copper pit type earthing has a deterioration factor in 3 years and maintenance

every year the watering down the pit. The ohmic values will measure at the different period of

the year vary drastically and sometimes reach failure level. There is no data available as the

earthing installation is not done in the organized sector so far and only in hand of unqualified,

illiterate traditional electrician without any electrical license whatsoever who used the quality of

copper, the poorest quality of coal(Powdered coal ) and third grade quality of salt and complete

the earth pit in a paltry some of Rs. 2000/-(Including there profit).

No comments! Only GOD can help and save the installation. Life is Uncertain.

CHEMICAL PIPE EARTHING: - It’s a maintenance free earthing and our experience over the

past two years on periodically checked by us and other manufacturer’s shows constant results

with respect to the ohmic values. Therefore the graphical representation of this type of earthing

is straight line with no noticeable change.

It gives you safe certain and sure protection to the installation.

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3. Cost of maintenance:-

PIT TYPE EARTHING: - In the pit type earthing some cost is required as under:

a) The cost of labour for watering at periodical interval.

b) The cost of water it is not free every where.

c) The cost of maintenance of the water pipe going to the pit which gets choked due to scale

formation and flow of water will be restricted or blocked.

d) The cost of charging by putting salt and charcoal which is undesirable and not permitted for

safety reason.

Chemical earthing: - The cost on account of maintenance is zero.

4. ADVANTAGE AND DISADVANTAGE OVER CONVENTIONAL EARTHING: - The

advantages and Disadvantages of both type of earthing has been mentioned and discussed as

length in the paragraphs given above. For detailed comparison please refer page no. 3 of our

catalogue the soft copy of which is attached for your immediate refrence.

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Earthing in Rocky/Hilly Areas .. How & Why ?

A. What is equipment Earthing:

Clause 7.0.1 of IS-3043-1987 states as under :The basic objectives of equipment grounding are :

1.To ensure freedom from dangerous electric shock voltages exposure to persons in the area

2. To provide current carrying capability, both in magnitude and duration adequate to accept the

ground fault current permitted by the over current protective system without creating a fire or

explosive hazard to building or contents,

3.To contribute to the better performance of electrical system

B. The efficiency of earthing System ;

1.It depend on the condition of soil

2.The resistivity of soil.

3.Design of the earthing system

4. Level of humidity to be maintained in the ground

5. The installation of the electrode either conventional PIT TYPE or the CHEMICAL

ELECTRODE deep into the ground below the FROST level or 2meters to 5meters deep so that

moisture level is obtained in the soil for efficient working /performance of the either of the

earthing systems is in vogue now a day.

C. Clause 8.6 of IS 3043 -1987 ;Effect of MOISTURE On earth RESISTIVITY:

Moisture content is one of the controlling factors in the earth resistivity .The moisture content is

expressed in percent by weight of the dry soil .Dry earth ways about 1440 kg per cubic meters

and thus 10 percent moisture content is equivalent to 144 kg of water per cubic meter of dry soil .

A difference of few percent moisture will therefore make very marked difference in the

effective of earth connection if the moisture content falls below 20 percent .The normal moisture

content of soils ranges from 10 percent in dry seasons to 35 percent in wet seasons, and an

approximate average of may be perhaps 16 to 18 percent .

It should be recognized, however, that moisture alone is not the predominant factor in low

resistivity of soil, for example , the earth rods driven directly in the beds of rivers or mountains

streams may present very high resistance to earth .If the water is relatively pure , it will offer

high resistivity and unless the soil contains sufficient natural elements to form a conductive

electrolyte , the abundance of water will not provide the soil with adequate conductivity.

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The value of high moisture content in the soil is advantageous in increasing the solubility of

existing natural elements in the soil , and in providing for the solubility of ingredients which may

be artificially introduced to improve the soil conductivity

Clause 8.7 IS 3043 -Effect of Temperature on Earth resistance The temperature coefficient of

resistivity for soil is negative, but negligible for temperatures above freezing point. At about 20

°C the resistivity change is about 9 percent per degree Celsius. Below 0°C the water in the soil

begins to freeze and introduces a tremendous increase in the temperature co- efficient, so that

as the temperature becomes lower the resistivity rises enormously .It is therefore recommended

that in areas where the temperature is expected to be quite low , the earth electrodes should be

installed well below the frost line .Where winter seasons are severe, this may about two meters

below the surface , where as in mild climates the frost may penetrate only a few centimeters or

perhaps the ground may not freeze at all .Earth electrodes which are not driven below the first

depth may have a great variation in resistance throughout the seasons of the year .Even when

driven below the frost line , there is some variation , because the upper soil , when frozen ,

presents a decided increase in the soil resistivity and has the effect of shortening the active

length of electrode in contact with soil of normal resistivity

Following Four Methods are Practical and used

Suggestions for installing earth electrodes In Hilly /Rocky /High resistivity soils

Method One . Artificial treatment of soil

Clause 8.8 0f IS 3043

Multiple rods ,even in large numbers, may some times fail to produce an adequately low

resistance to earth. This condition arises in installations involving soils of high resistivity

.The alternative is to reduce the resistivity of soil immediately surrounding the earth

electrode .To reduce the soil resistivity ,it is necessary to dissolve in the moisture ,normally

contained in the soil , some substance which is highly conducive in its water solution .The

most commonly used substances are sodium chloride(NaCl),also known as common

salt,calcium chloride(CaCl2),Sosium carbonate (Na2CO3), Copper sulphate (CuSO4). Salt

and soft coke , and salt and harcoal in suitable proportions

Clause 8.8.1

With average or high moisture content, these agent form a conducting electrolyte throughout

a wide range of earth electrode. Approximately 90 percent of the resistance between a driven

rod and earth lies within radius of two meters from the rod. This should be kept in mind

when applying the agents for artificial treatment of soil. The simplest application is by

excavating a swallow basin around the top of rod , one meter in diameter and about 30 cm

deep, and applying the artificial agent in the basin The basin should be subsequently be filled

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with water several times , which should be allowed each time to soak in the ground ,thus

carrying the artificial treatment ,in electrolyte form ,to considerable depths and allowing the

artificial agents to become diffused throughout the greater part of effective cylinder of earth

surrounding the driven rod.

Clause 8.8.3

In most of the soil conditions, the artificial treatment may be effective over a period of many

years .However it is recommended that annual or biannual measurement of earth resistivity

should made to find out if additional treatment is needed

Clause 8.8.4

In using this artificial treatment, the possible corrosive effect of the salt on the driven rods

and connections should be considered. The possible contamination of domestic water supply

should also be considered

Method Two( Installing electrode at angle of 30° to Horizontal

Clause 9.2.2 Last para

In cases where impenetrable (which cannot be dug deep) strata or high resistivity soil occur

at relatively small depths , considerable advantage may result from driving rods at an angle

of about 30° to the horizontal , thus increasing the length installed for a given depth .

Method Three (L Shaped Electrode)

This method is used by manufacturers of electrodes in the hilly or rocky areas where digging

is not practical even by use of pneumatic hammers or Rock Drills. In such situations L

shaped electrodes are designed .To quote an example a 3000mm electrode will be designed

with small arm of the L as 600mm and long arm 2400mm .it is seen that even in rocky /hilly

areas one can manage to dig manually up to 600mm (2 feet) .

Method Four ( Combination of L Shaped electrode and replacing the soil with

AGRICULTURE SOIL

This method is combination of replacing the soil with agriculture soil and providing the L

shaped electrodes.

This method is very extensively used by the manufacturers of electrodes and has been found

to give very good earth resistance values, and does not need periodic maintenance of soil.

This method has proved more durable and reliable

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Summary & Conclusion

The Is 3043 -1987, NEC 2011 and Indian Electricity Rules (Latest) provide the requirement

of earthing considering minimum and essential safety parameters for various applications in

domestic ,commercial , industrial , generation , transmission and distribution levels of

electricity .

In our sincere opinion based on our years of experience in the electrical safety business, the

judgment of the Project Engineer should be adjudged as FINAL since he is fully aware of the

site conditions and other parameters. Safety is Very Essential, let us RESPECT the judgment

of PROJECT PERSONNEL

The volume of the Dug Up area in case of L shape earthing and earthing inclined at 30 ° will

be more than that of regular Cyliderical earthing , the use of BACK FILL COMPOUND will

be minimum two bags more than that what is recommended by us

Our Final Recommendation

The L shaped earthing installed with Replacement of soil with AGRICULTURE SOIL in

such difficult areas is the final , positive , no failure method.

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INSTALL CHEMICAL EARTHING. HOW?

About Us

We are a professionally managed upcoming company engaged in providing latest

Earthling/Grounding systems and solutions ensuring Safety of Property, People and Equipments.

Thank You

Thank you for purchasing an SBA POWER Maintenance Free Chemical earthing for your

electrical equipments/installations. We have created this product for you, keeping electrical

safety in mind and have paid special attention to the quality of material used and ease of

installation

Installation Procedure:-

The Earthing electrode must be installed as per the following Procedure:

1. The location of the site to be decided or identified by the staff (Electrode should never be

installed in the proximity to a metal fence).

2. The respective boring will be of appropriate depth of 2 or 3 meters depending upon the

size of electrode selected and minimum 150-200 mm Diameter.

3. The bore will be watered for 24 hours or more in normal soil conditions .In case the soil

condition is rocky or sandy then watering should be carried out for 48 hours or more at

the discretion your engineering staff or else we should be consulted.

4. After the appropriate watering is done and the bore is cleared off mud etc. formed there

in the bore .The electrode must be inserted at the centre of the bore.

5. The RIYA GCM compound which is supplied in the packs of 20 Kg. each must be mixed

with the water of appropriate quantity to make thick slurry of the compound and poured

around the electrode gradually to reach upto the ground level.

6. The slurry of the RIYA GCM poured in the bore around the electrode will take curing

time of seven to ten days to mix up with the soil and attain the natural properties of

surrounding soil.

7. The first testing of ohmic values for preliminary result can be carried out on the day of

installation and the final results can be taken after curing period is over.

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8. The earthing electrode can be connected after the preliminary test and safety of the

equipment can be ensured.

9. In certain cases of rocky and stony areas where it is not possible to go2-3 meter Deep

then the manufacturers recommendation to install horizontal electrode of L-shape (

Available on prior order)where the small arm of the L will be of 600mm, or same

horizontal electrode can be installed at an angle of 30 degree from the ground level. In

such cases the RIYA GCM compound will be 50% more than the vertical installation.

Important Precautions:-

Handle carefully and do not plunge an electrode.

Do not apply any extraordinary force/pressure during installation.

Never try to disassemble, repair or otherwise tamper with an Earthing Electrode.

Do not strike it with hammer or other object and never step on it.

Avoid prolonged physical contact with any type of metal fence.

It should be installed away from the flowing water or drainage system.

Always use very high standard wire/accessories to connect Earthing Electrode

with the equipments.

Eradicate all packaging material such as plastic cover / bubble paper prior to

installation of an Earthing Electrode.

At all times it is recommended to apply petroleum jelly over an Earthing Electrode

terminal to shield against corrosion.

This product is designed and produced only for earthing/grounding purpose.

Method of measuring of newly installed Earth Electrode Resistance:

1. The method used for testing of the earth resistance Fall of potential method.

2. The Fall of potential method measures voltage and current between spikes and earth

electrode hence the unknown resistance is known.

3. The instrument used for the purpose known as Earth Tester with four terminals out of

which two are shorted and therefore three terminals are used.

4. The electrode under testing is known as main electrode and the two other electrode which

are use for testing supplied with the instrument are known as auxiliary electrodes.

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5. The main electrode is placed in straight line with the two auxiliary electrodes so that the

extreme distance between two electrodes is 30 meter i.e. between main electrode and

potential electrode.

6. If the 30 meter distance is not possible in straight line while testing then one can divert

the angle subject to maximum 45 degrees. This method will of course sacrifice certain

value of the earth resistance under test.

Testing & Measuring:-

The preferable meter is Earth Tester manual. The advantages of the manual meter are to avoid

the wandering of the instrument pointer as explained below:

Article No. 37.1.1 from IS 3043:1987

“In most cases, there will be stray currents flowing in the soil and unless some steps are taken to

eliminate their effect, they may produce serious errors in the measured value. If the testing

current is of the same frequency as the stray current, this elimination becomes very difficult and

it is better to use an earth tester incorporating a hand-driven generator. These earth testers usually

generate direct current, and have rotary current reverser and synchronous rectifier mounted on

the generator shaft so that alternating current is supplied to the test circuit and the resulting

potentials are rectified for measurement by a direct reading moving-coil ohm-meter. The

Presence of stray currents in the soil is indicated by a wandering of the instrument pointer, but an

increase or decrease of generator handle speed will cause this to disappear”.

Precautions:

1. The source of current supply shall be isolated from the supply by a double wound

transformer.(refer to the article 37.1.2 from IS 3043:1987)

2. At the time of test where possible, the test electrode shall be separated from the

earthing system. (refer to article 37.1.3 from IS 3043:1987).

3. The auxiliary electrodes usually consist of 12.5mm diameter mild steel rod driven up

to 15 cm into the ground as suggested here under.

4. It is suggested to insert the testing electrode in the just to make the contact with the

earth. The length of our electrode is max 3 meters therefore the insertion of spikes

should be 15cm which comes to nearly 6 inches. Just enough for the spike to stand

firmly on the ground.

The contact with the earth is only criteria for testing the ohmic values earth

resistance and the electrode should normally stand on the ground.

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UPKEEP BY USER:

The User must take into consideration following factors which may affect the earth system in

future while in operation:

1. Maintenance of the earthing system by the team of their engineers (user).

2. Any Weak links developed during the course of working that is due to Oxidation of the joints

or loosening of the fasteners.

3. Any mechanical damage to the earthing pit or connecting strips.

4. Disconnection of 1 or 2 earthing pits, either by mistake of electrician or oversight.

Keeping into above factors 2 or 3 earthing systems may not be effectively working for the couple

of months therefore it is necessary to make a grid of the higher no. of earthing pits to ensure the

constant low ohmic values under adverse circumstances.

EARTH RESISTANCE OF AN ELECTRODE - MEASUREMENT

When an electrode system has been designed and installed, it is usually necessary to measure and

confirm the earth resistance between the electrode and “true Earth”. The most commonly used

method of measuring the earth resistance of an earth electrode is the 3-point measuring technique

shown in Figure. This method is derived from the 4-point method, which is used for soil

resistivity measurements.

The 3-point method, called the “fall of potential” method, comprises the Earth Electrode to be

measured and two other electrically independent test electrodes, usually labelled P (Potential)

and C (Current). These test electrodes can be of lesser “quality” (higher earth resistance) but

must be electrically independent of the electrode to be measured. An alternating current (I) is

passed through the outer electrode C and the voltage is measured, by means of an inner electrode

P, at some intermediary point between them.

The Earth Resistance is simply calculated using Ohm’s Law; Rg = V/I.

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SYSTEMS OF GRID EARTHING

Why & How ?

Reasons of Grid Earthing: -

1. To manage very high fault currents So that the low ohmic value of earth resistance will reduce

the effective watt loss thereby controlling the heat generated in the system.

2. To maintain very low level of ohmic values of earth resistance like 0.1, 0.2 etc. so that the

sensitive electronic equipment don’t malfunction & there electronics cards & PCB’s don’t fail &

get damage electrically.

System at a particular plant:-

1. The connected loads at your plant for each equipment are not heavy & not at an extra high

voltages as well.

2. The reason for maintaining the value of resistance appears to us for preventing the malfunction

of the electronic equipment & there electronic cards.

How can we maintain the low ohmic earth resistance:-

The examples are given below:-

Formula to calculate the Resistance in Parallel:-

If there is n resistance connected in parallel.

1/R=1/R1+1/R2+1/R3+1/R4+--------------------------------------------+1/Rn.

When three earthings are used in a GRID:-

CASE-I

R1=0.6, R2=0.8, R3=0.4

1/R=1/0.6+1/0.8+1/0.4

1/R=1.66+1.25+2.5

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1/R=5.41

R=0.18 ohms.

CASE-II

R1=0.4, R2=0.8, R3=1.2

1/R=1/R1+1/R2+1/R3

1/R=1/0.4+1/0.8+1/1.2

1/R=2.5+1.25+0.833

1/R=4.58

R=0.218ohms.

When four earthings are used in a GRID:-

CASE-I

R1=0.4, R2=0.6, R3=0.8, R4=1.2

1/R=1/0.4+1/0.6+1/0.8+1/1.2

1/R=2.5+1.67+1.25+0.833

1/R=6.25

R=0.16 ohms.

CASE-II

R1=0.5, R2=0.7, R3=1.0, R4= 1.2

1/R=1/0.5+1/0.7+1/1.0+1/1.2

1/R=2+1.43+1.0+0.83

1/R=5.26

R=0.19 ohms

We have given two cases for each type of grid earthing i.e. three earth systems & four Earth

systems.

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Our recommendations are for four earth systems to maintain a long term low ohmic values

because of the following factors:-

1. Change of a soil condition for a period of a time is choosing a different location for the

earthing system in the same premise.

2. Change of climatic condition:

a. Extremely dry climate- SUMMER

b. Extremely cold climate- WINTER

c. Extremely humid climate-RAINS

d. Occasionally scanty rain fall which is assumed to be less than 250mm in a year which is

unlikely in any area .

Our recommendations are based on the effect that the equipment will work throughout the year

in all climatic condition.

WHY EARTHING NEAR TO THE EQUIPMNT

Subject: - Location of Earthing?

Question: Should it be near to the point of application/Equipment or away from it?

Answer: It must be near to the point of application.

Reason:

Please read on!

1. OLD TRADITIONAL SYSTEM:-

I) The conventional pit type copper plate Earthing with large Quantity of Charcoal & Salt was

requiring large area of about 4’x3’or 6’x4’ & depth used to be 20’ to60’ (7 to 20 mtr)depending

on the soil condition.

II) This much area was conveniently available in the factories/office premises in earlier days

when the space was not constraint.

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III)The distance between the earth pit & the point of application used to be few meters may be

50-100mtrs & therefore to maintain the low resistance of the earthing wire from the earth pit to

the machinery the copper wire of 8/10 swg was used.

IV) The copper wire thus used was cash & carry item for professional wire cutters who used to

cut the wire at the first opportunity there by disconnecting the earthing system & causing an

electrical danger to the system.

2. PRESENT MODERN SYSTEM:-

I) The space is become expensive & in short supply.

II) The conventional pit type earthings is very cumbersome, laborious & occupies more space in

term of sq. mtr & it is being replaced with chemical pipe earthings.

III) The advantages of pipe earthing are:-

a) It needs a bore of 250-300mm dia & the depth of 2 to 3 mtr.

b) It is a neat & clean installation.

c) Doesn’t spoil the look of the office or factory.

d) It is conveniently covered up which can be flagged showing the location of the earthing.

e) The pipe earthing is a compact unit & can be installed very near to the equipment hardly 2-5

mtr away from the equipment.

f) The closeness of the earthing has a advantage of providing very low resistance value to the

system which requires less length of the wire (AS resistance is directly proportional to the length

i.e. the smaller the length, it is better for earthing)

g) Since the length of the earthing is required is very small in the installation of pipe earthings

due to nearness to the equipment.

h) The G.I. strip of cross section area of 10x3mm or more are used for connecting the pipe

electrode to the equipment.

I) G.I. wire is not favorite of wire cutters so there are no chances of disconnection of wire cutting

or theft.

j) The copper wire of 8/10 swg which was used earlier were subjected to more mechanical

damages because of very low cross section area & the round wire is more subjected to more

cross sectional damage than the rectangular strip of 10x3 mm or above.

21

CONCLUSION:- In view of above application the earthing electrode close to the point of

application or equipment are more desirable for electrical & electronics equipment which

demand low value of ohmic resistance through out the year under all working condition i.e.

extreme dry ,extremely cold or wet climates.

22

PARAMETERS OF GOOD EARTHING.

What Are These?

A. The Good earthing have three parameters:

A.1. The size of the current carrying conductor should be of sufficient cross section

to withstand the fault current generated at the time of fault and the pipe containing it

should be of adequate dimension to withstand with electrical and thermal stress

generated during the fault. We have considering the load factor which you are given

to us we had recommended you a earthing of 88mm X 3000mm which is more than

for most of industrial requiremenst.

A.2.The second factor is heat dissipation of the electrode: it is already know that the

heat is dissipated from the surface of the electrode system. In a conventional plate

earthing the plate used are generally 600mm x 600mm = 360000 sq. mm of surface

area.

In our case the surface area is πDL which is equal to 3.14 x 88mmx 3000mm

=828,960 which is much more than the surface area of the plate earthing .

A.3.The maintenance of moisture: In the conventional earthing the salt is hygroscopic

substance and which works initially well but thereafter in the course of time the salt

becomes water and dries up totally and hence no hygroscopic properties are left . It is

therefore the ohmic values of plate earthing is change drastically and there most of

the engineers provide additional watering pipe to keep the ground moist which is very

erratic and unreliable and subject to human forgetfulness and negligence of the

workers involved.

In our case the chemical used is aluminum silicate which absorbs water 13 times of

its weight and doesn’t dissolve in the water. The slurry of the chemical which is made

and used while installing the earthing system remains moist throughout the life. The

smallest rain fall of 2.5 cms per year in the area of installation , the aluminum silicate

has a property of sucking the water from the surrounding soil and maintain the

23

moisture around the electrode. Because of the property of the chemical the values of

the earthing electrode are almost constant with a very minor variation in extreme heat

, extreme winter during which period the humidity is very low.

B. Life of the chemical earthing system: The life of the chemical earthing system the

concept of which was started in Europe 25 years back has been confirmed around 15

years plus in use in different installation . In India the concept is 13 years old and

there are generally satisfactory report from everywhere and it can be reasonably

assured the life of the chemical earthings is 15 years and above.

C. The advantage of this earthing system doesn’t need any type of maintenance unlike

conventional type of earthing system like watering etc.

D. The chemical earthing doesn’t need any maintenance what so ever it is a fit and

forget type of earthing. Of course it is understood that general upkeep of the

termination joint is necessary in any electrical installation for continuous carrying of

the current and low contact resistance /joints in the system. We emphasis that the

good engineers do understand the difference between the upkeep and the maintenance

of the earthing system.

We repeat that upkeep is different from maintenance.

24

Select the size number of earthing for an Industry – How?

Type of Industrial loads :

1. Heavy industrial motors say 50 kw and above to run certain processing machines in sugar,

Paper, steel, textile, and heavy industries , arc/blast furnaces etc, EOT cranes,Passenger /goods

lifts, material equipment i.e conveyers

2. The work shop machinery less than 50 kw including FHP motors i.e lathe machines, drilling

machines, grinding machines, Hack saw machines, shearing, cutting and bending machines,

power /hydraulic presses, injection molding machines. Portable tools and other such light

machinery. and water pumps

3. The CNC machines, Speed drives (Vfd etc) and other technological advanced computerized

equipment

4.Industrial lighting loads. A. mercury vapor lamps, sodium lamps Cfl lamps incandescent and

fluorescent tubes , general purpose fans and industrial exhaust fans.

5 Air conditioning plants , ventilation equipment etc

a.The Individual body earthing is recommended for EOT cranes, Lifts, arc/Blast furnaces,

conveyers systems

b.Other motors can be connected in parallel with common main earthing , Precautions must be

taken that distance covered is not vey long so that circuit impudence is not increased causing

high earth resistance . In such case the the experience of the engineer in charge is very important

to decide on the distance. We can recommend more than two conductors to run in parallel with

proper termination of joint and good quality of nuts, bolts, spring washers and flat washers.. To

avoid rusting of joints it is suggested to use the stain steel hardware and good quality of fasteners

to avoid loose /weak joints

c.The above precautions are to be observed in machinery listed in Para 2 for workshop

machinery etc.

e. The earthing for the fixtures of the lighting equipments can be earthed in parallel with single

earthing keeping the precaution termination of joints and taking that weak /loose joints are

strictly avoided. It is not necessary to provide double earthing or two earthing in parallel simply

because engineering department cannot ensure reasonably strong and electrically good joints

f. Cnc machines and other computerized equipment as per manufacturers’ recommendation. One

must use separate earthing for the body and neutral . neutral earthing is is Compusory for

25

controlling FLOATING neutral voltages which might other vise damage the electronic PCB `s

in the equipment

g. For DG sets , transformers ,and severs /ups systems 2 nos. earthing are necessary for body and

neutral . The is 3043 -1987 is clear on this concept

h.The separate single earthing is necessary for the body and neutral of the protective equipment

6 Servers , large nos computers in net work controlled through online UPS systems

7. DG sets for stand by supply

8.Ditribution Transformers or Step up /Step down transformers.

9. Servo Voltage stabilizers, isolation transformers , ACB`s , Change over switches .and other

such controlling and protective devices.

26

Why Accept GI Electrode Vs Copper?

A. ZINC:-

Zinc oxide will be formed during the process naturally as the mineral zincite.

Solubility:

Practically insoluble in water; soluble in dilute acetic or mineral acids, ammonia, ammonium

chloride, ammonium carbonate, and fixed alkali solutions; insoluble in alcohol.

It exhibits piezoelectric characteristics in thin film form. Such thin films can be deposited by

process like sputter deposition. Zinc oxide is also luminescent and light sensitive. Zinc oxide is a

unique Dielectric Strength material that exhibits semiconducting and piezoelectric dual

properties.

Zinc oxide finds applications in: VARISTORS which are used to prevent voltage surges in

devices like mobile phones.

Flammability: Zinc oxide is not combustible.

Extinguishant: Used as an extinguishant that is suitable for the materials involved in the

surrounding fire.

Metal – Protective Coatings

Zinc metal powder (zinc dust) and zinc compounds have long been utilized for their

anticorrosive properties in metal-protective coatings, and today they are the basis of such

important specially metal primers as Zinc Chromate primers.

Zinc dust-Zinc Oxide paints are especially useful as primers for new or weathered galvanised

Iron. Such surfaces are difficult to protect because their reactivity with organic coatings leads to

brittleness and lack of adhesion. Zinc dust-Zinc Oxide paints however, retain their flexibility and

adherence on such surfaces for many years. Zinc dust-Zinc Oxide paints also provide excellent

protection to steel structures under normal atmospheric conditions, as well as to steel surfaces in

such under-water conditions as dam faces and the interior of fresh water tanks.

COPPER:-

Metal oxides are generally not very good conductors. In fact, most are

27

dielectrics and hence non-conductors. Certainly,

copper and aluminum are much better conductors than their corresponding

oxides at any temperature linemen will encounter.

Copper, lead, and aluminum oxides formed by corrosion are decidedly poor

conductors. Even if you are not an electrical engineer but you know if you let the terminals of a

battery become corroded, the battery no longer delivers electricity

(i.e. the corrosion products are insulators).

Most metals, including copper and aluminum, form thin metal oxide film

layers when exposed to air for even a brief time -- this is what makes turn dull after a few days

or weeks.

Copper is generally used as TINNED COPPER to avoid oxidation effecton the bare copper

conductors when used.

The Termination is Generally done by soldering the multi strands of copper wire for effective

termination and to avoid oxidation at the point of contact.

The termination at bulk loads is normally done by LUGS duly filled with soldering compounds

or by very effective Crimpping.

The copper oxide is poor conductor is proved by the practice of cleaning the copper contacts in

the Switchgear by emery paper /sand paper periodically to maintain the contact conductivity.

The copper does gets deteriorate due to oxidation and get pitted in switchgear contacts due to

oxidation requiring replacement ofcontacts.

Tha above points prove the inefficacy of copper conductivity due to oxidation and it is our daily

experience of electrical engineers.

Note

The current density of copper with respect to iron /zinc is of course higher and it is taken care by

using a better cross section of of ear thing strips i.e 50x6 mm (300sq mm)or 25x6mm(180

sqmm) where as in copper strips the cross section will be much smaller for the same design.

CONCLUSION:-

In view of the facts given above it is recommended to use the Galvanized steel strips against the

convential copper strips.

28

Technical Specifications

Group A- GI PIPE +GI STRIP

S.No. Model No. Dia

(mm)

Length

(mm)

Conductor

size(mm)

Riya GCM

(kg)

Terminal

dia

(mm)

Capacity

1. SBA48/2/G 48 2000 25x3 20 kg 12 50 KVA

2. SBA48/3/G 48 3000 32x3 30kg 12 75KVA

3. SBA22/G 58 2000 25x6 20 kg 12 150KVA

4. SBA32/G 58 3000 32x6 30 kg 12 350 KVA

5. SBA23/G 88 2000 40x6 30 kg 14 850 KVA

6. SBA33/G 88 3000 50x6 40 kg 14 1750 KVA

Group B-GI PIPE+ Cu Strip

S.No. Model No. Dia

(mm)

Length

(mm)

Conductor

size(mm)

Riya GCM

(kg)

Terminal

dia

(mm)

Capacity

1. SBA48/2/CG 48 2000 25x3 20 kg 10 200 KVA

2. SBA48/3/CG 48 3000 32x3 30kg 10 350KVA

3. SBA22/CG 58 2000 25x6 20 kg 12 500KVA

4. SBA32/CG 58 3000 32x6 30 kg 12 1500 KVA

5. SBA23/CG 88 2000 40x5 30 kg 14 2000KVA

6. SBA33/CG 88 3000 50x6 40 kg 14 3000 KVA

Group C-Cu Pipe +Cu Strip

S.No. Model No. Dia

(mm)

Length

(mm)

Conductor

size(mm)

Riya GCM

(kg)

Terminal

dia

(mm)

Capacity

1. SBA40/2/C 40 2000 25x3 20 kg 12 450 KVA

2. SBA48/3/C 48 3000 32x3 30kg 12 600KVA

3. SBA22/C 50 2000 25x6 20 kg 12 1000KVA

4. SBA32/C 50 3000 32x6 30 kg 12 2000 KVA

5. SBA23/C 58 2000 40x5 30 kg 14 3000KVA

6. SBA33/C 58 3000 50x6 40 kg 14 5000 KVA

29

Eletricity is Polluted Today ! Why ?

POLLUTION in Electrical power Systems or voltage and Current contaminations of the pure

waveform occurs in any system due to Over -voltage Surges, Under-Voltage Sags, Transients,

Short Term Disturbances or due to harmonics.

Harmonics can be defined as the Voltages or Currents of frequencies tha are integral Multiple of

the fundamental line frequency i.e 50 Hzor60 as the case may be.Their combination with the

fundamental harmonics leads to the distortion of the pure waveform.

Sources of Harmonic Distortion:

Primary Non Linear loads draw current in irregular manner resulting in irrefular Voltage drops

and Harmonic

Distortion of the Voltage in Power system.

Secondary Distortion in the Voltage induces irregular currents in the linear loads resulting in the

transfer of External Import of Harmonics from external sources like neighbouring plants, etc

a) Internal Internal Sources: all loads using non linear components (thyristors, power

diodesetc)

b) Adjustable Speed/ variable frequency drives

c) Solid - state Uninterrutiple power Suppliers (ups )

d) Electronic Power Converters, Rectifiers

e) Programmable Controllers

f) Induction Furnaces

g) Arc Furnaces and Welders

h) Arc Lighting (fluorescence, mercury vapour)

i) Electronic Lighting Ballasts

j) Personal Computers

Effects of Harmonic Distortion:

a) Overtheating and additional losses in Transformers, Motors, Cables and Capacitors.

b) Interference with communication and control signals

c) Metering errors

d) malfunctioning relays

e) False O Peration of Electronic Controls in Variable Speed Drives & Electronic Breakers

Resonances

f) Disturbance of computers and computer controlled Equipments.

g) Disconnection or Failure of Non - detuned Capacitor Banks

h) Increased Losses in Destribution Gear and Transformers

i) Damage to Converters

j) Uncontrolled triggering of power Switches/ Fues

k) Overvoltages

30

Symptoms of Harmonic Distortion:

a) Tripped Circuit Breakers

b) Failed Capacitors

c) Blown Fuses

d) Motor Winding Failures

e) Overheated Transformers

f) Misfiring/ Breakdown of AC / DC drives

g) Insulation Failures

h) Computer failures

i) Telephone interference

As modern manufacturing equipments continue to employ power Electronics (VFD's, AC and

DC Drives etc) for faster and efficient production levels, Generation of harmonics and the

Corresponding Ill -effects of the same are being felt all over the manufacturing sector including

Software Industry, Commercial Complex etc. It is critically important to understand the effects

of harmonics and use suitable solutions for dependably improving the power Efficiency and

power Quality to take full advantage of the Modem Manufacturing Equipments and System.

At SBA POWER , backed with on - hand working experience under various site conditions for

the last 4 years, we provide Solutions for Power Efficiency and Power Quality. through quality

and reliable chemical earthing.

Suggestions for Electrical Engineers and Plant Engineers

SOLUTIONS: A

For Power factor Correction only:

In cases Where the normal acticities fo manufacturing /production are not effected and just that

regular capacitor failures associated with the switchgear and controlgear malfunction are

reported , it is advisable to provide solutions for dependable Power factor Correction alone and

not aim at Filteration of Harmonics. This is comparatively a simpler exercise as the same can

beachieved by providing detuned PF correction System for PF Improvement.

It is important to understand that , in such cases as cited above, capacitor failures are mainly due

to uncontrollable over-current conditions due to Series or parallel Resonance at particular

harmonic frequencies generated by the nonlinear loads or are present in the system by virtue of

import or harmonics from other loads of supply grids. Though these Harmonics may not

adversely effect the production activities by virtue of loads that are non-tuned or are not affected

by these harmonics , but these definitely effect the capacitors by tuning are resonant frequencies.

The simple solution in these cases is to "detune" the capacitor banks using L-C circuits . By

Detuning a circuit, we force the resonant frequencies below the lowest order of Harmonic

present in the System . This in effect corrects the PF at the fundamental frequency and at higher

orders operates as a detuned system.

31

B.For power Factor Correction with Harmonic Filtration:

In cases where the normal activities of manufacturing / production are seriously effected due to

Harmonics, It becomes imperative to filter out the harmonics present and get the overall THD

levels below the accepted levels as per IEEE standards In such cases, we strongly recommend

the use of Harmonic Filter Equipments alongwith PF Correction for production and Energy

Efficiency.

32

Problem of Floating Neutral Voltages – How & Why ?

The Earthing in the industry has to make the requirements full filled.

1. Basic ohmic values of the Earth resistance which are vey desirable to be less than 5 ohms

so that the persons operating on machines and equipment are protected against the

electric shocks when they come in to contact with metallic parts of the equipments when

they work with.

2. The low ohmic values however very essential to provide safety to the buildings because

of leakage current which inadventarily takes place because of damage to the insulation of

electric cables and wires distributing the current in the distribution circuit. The leakage

currents are in milli amperes and therefore need to be protected through protective

devices in the backup protection of the installation.

3. The protection against floating neutral voltages :

Let’s explain what NEV (Neutral to earth voltage) is?

It is voltage b/w neutral and earth which should be theoretically zero. In electrical

Engineering it is a well known fact that Earth is at zero potential and so is the neutral

point of the star connected supply line.

4. When you connect a voltmeter b/w Earth and Neutral point it should be zero.

N E

5. Neutral voltages are today known as Floating neutral voltages as the voltage change with

the change of load condition in the existing plant or in the neighboring plant. The

voltages keep on changing during various times of the day and even week or in a month

as the parameters of balance load will change.

6. Neutral currents are calculated as per the following formula:

I= {(A²+B²+C²)-(AB+BC+AC) }½

Let’s put the values in the above formula,

A=10,B=10,C=10

Then value of neutral current comes,

I=0A

Other example is, A=9,B=8, C=7

V

33

Then value of neutral current comes,

I=1.73 A because of load unbalanced

V=IR

R=2 ohms ohmic value of Earth resistance, then V= 1.73x2= 3.46 V

When R=3 ohms, V= 1.73x 3= 5.1 V

When the load is unbalanced the Phase angle of the star point is changed as per the following

calculations :

Voltage b/w phase A & B is 415 V

Angle B/w two phases 120 degree

Therefore the change of voltage per degree of change of phase angle 415/120= 3.45 degree

A B

120

415 v N

C

In the above examples when the load current varies b/w 9, 8 & 7 A the phase angle get changes

nearly 1 degree which is reflected in the calculation given above. This is nearly 3.51 volts.

Conclusion: as you will observe from the data given above that the following factors are not in

control of Earthing systems.

A. The load current will vary throughout during the day and will also differ substantially

during the various periods of the month or in a year.

B. Electricity travels always from An easier path and therefore it will travel from the

neighboring industries or installations which will get reflected from the star point and

therefore the NEV is always known as Floating Neutral Voltage and this voltage cannot

be controlled by Earthing systems.

C. Following suggestions are given:

i. Balance the loads periodically to ensure that the floating Neutral voltages are

under control. Checking of neutral point and outgoing connections time to time.

34

ii. The most of the PCB cards are designed for operations of 9 v-18 V and the

small neutral voltages up to 9 volts are not likely to damage the PCB. It will of

course the manufacturers of molding machines of such equipments are

abundantly over cautious on insisting upon the clients to maintain the low

neutral voltage at the time of commissioning the equipment. The technical

executives of machinery manufacturers also have knowledge that the neutral

voltages will float in higher level without their knowledge depending on the

condition of load when they leave the installation after commissioning.

iii. The apprehension of the neutral voltages floating to higher levels makes the

manufacturers unnecessarily very very over cautious and insist upon the user

low neutral voltage rather than persisting the customer to do the electrical audit

time to time and balance the loads which in their per view.

iv. Electrically speaking it is none of the business of the user to run an industry and

electrical equipments on the unbalance loads. The Electricity rules as a user

guideline doesn’t permit in any way to unbalance the loads. If they do it they do

it at their risk and cost.

The safest way to ensure the neutral Earth voltages down come into picture

and you want to play 100% safe please don’t use supply neutral at all but use an

Isolation Transformer of Delta- Delta combination with 1:0.95 i.e. is the final

and last positive solution if you don’t want to take risk.

35

Floating (NE) Neutral to Earth Voltages–Causes and Remedies

Stray voltages or neutral-to-earth (NE) voltages are an on going problem in many areas supplied

from single phase and Multi-grounded services and where current levels on the grounding

systems are above the perception threshold for either animals or humans. Typical locations are

clusters of medium and large scale industries dairy farms, feeder and confinement operations,

swimming pools, water Systems, residences, etc. Stray voltages (NE) can come from many

sources, both from on and off the site. In most cases, the problems are the result of several

simultaneous sources combined.

On-site stray voltage can usually be resolved through a program of upgrading and reconnecting

the wiring system and its various loads. Off-site stray voltage, which is of particular interest to

the power supplier, can result from primary neutral currents, off-site faults, marginal grounding,

etc. of-day also adding to the confusion. Although it may go away, there can be no assurance that

it will cause it. A loose neutral connection can cause a stray voltage or even a fault at another

service may cause it. In many cases, a poor primary neutral connection is masked by the

grounding system of the customer, giving no obvious signs of a problem even existing unless a

stray voltage check is made. This is a neutral-to-earth voltage and can easily be measured with

and volt meter and a remote ground.

STRAY VOLTAGES:

Electrical engineering specialists have known for some time that low non-lethal voltages

accessed to dairy animals can cause mastitis, affect animal behavior and materially reduce milk

production. More recently, the same voltages have been known to cause problems in industries,

computerized equipments, parlors, poultry houses, water fountains, swimming pools and

homes.Various studies have shown that voltages about 0.5 volts can be detected by animals that

are very wet as is a dairy cow being washed down prior to milking. There is some evidence that

humans are susceptible to a threshold voltage of approximately1 volt when they are wet. Thus

voltage below 10 volts, which previously the electrical industry has largely ignored as a non-

problem, now, has a much greater interest and appreciation.

Since these low voltages may now have many sources, they have been variously called “tingle

voltage”, extraneous voltage, or more generically called Stray Voltage. A number of studies and

findings have identified methodical and logical methods for identifying the sources of the

problems and eliminating them.

ON-SITE:

On-site voltages caused by on-site wiring problems and electrical equipment defects can readily

be isolated by turning the service entrance switch off. Then operation of individual circuits and

pieces of equipment can identify specific

Problems. Examples would be failed water heater elements, defective electric

Motors and pumps, broken or damaged wiring insulations, etc.

The portion of the voltage that remains on the ground system after the service

Entrance main is turned off is obviously off-site in origin. However, neutral-to earth Voltage

which increases with on-site load may also be considered off-site in nature if it is due to the

36

increased load on the primary neutral. This phenomenon can lead to confusion when attempting

to resolve the overall problem. Basically, All on-site problems can be eliminated with proper

wiring and associated Good wiring and equipment practices.

OFF-SITE:

There can be several sources of voltages that originate off-site. Regardless of the Sources, the

stray voltage must be identified and eliminated. Common off-site sources include power supplier

neutral, telephone ground, cable television, cathodic Protection on buried pipelines and even

faulty electrical equipment on another site by far the most common off-site source is the power

supplier neutral. It is often the entire source of stray voltage, in other instances; it may be

contributing only a portion of the stray voltage. However, this neutral primary current caused

contribution may well be above the 0.5 volt threshold and must be eliminated by appropriate safe

and cost effective methods.

SOURCE OF POWER SUPPLIER NEUTRAL-TO-EARTH VOLTAGE;

It seems to be common practice that electric power suppliers utilize a multigrounded distribution

system. Both three and single-phase power lines are equipped with a neutral to return current

back to their substation. Even three-phase lines cannot be balanced to eliminate all current flow

on the neutral. Even if they were expertly balanced, the addition of single-phase load would

cause an imbalance. Electric current requires a change in voltage commonly called voltage drop

in order to push it along a conductor. As load on the line builds, there will be a proportional

increase in voltage. Thus there is a small voltage usually present on power line neutrals. While is

does not normally represent and lethal hazard, it may cause problems in highly sensitive

situations like computerized equipments , servers, ups, vfd , eapbx,automated computerized

machine tools , graphic design and printing machines and milk dairys, parlor or a swimming

pool.

Since the power line neutrals are grounded at every service, every transformer, and at least four

times per mile, it becomes quite evident that voltage on the primary neutral will vary as the load

varies and as the electrical resistance of the grounding electrodes change. The resistances of the

grounds change as soil moisture changes. An example is the grounds lose their conductivity as

the ground dries out in dry weather(summers and winters) and regains it as moisture is added

during rainy conditions.The greatest electrical loads occur in severe temperature conditions,

typically on a

hot dry summer day. This is just the time the neutral grounding system has its lowest current

carrying capacity thereby increasing the voltage on the neutral. The result is that voltage

problems from power line neutrals can appear and go away in a seemingly mystical fashion.

Also, load on the line almost always varies with time-

37

THE INTERCONNECTION PROBLEM

Electric Power distribution systems normally require the primary neutral and the secondary

neutral to be interconnected for two reasons.

1. The interconnect provides an alternate path for current flow in the event

these is a failure in the transformer. This alternate path assures that the

Primary fuse will blow if for example, the primary should drop into the

Secondary.

2. The interconnect also provides access to site grounding to help

dissipate lightning. However, the interconnect applies any voltage on the primary neutral to the

secondary neutral. The voltage will follow the secondary neutral into the service entrance panel

neutral bar, through the bonding jumper required by the electric supply company, to the

equipment grounding bar and from there to every piece of grounded electrical

Equipment in the facility. We shouldn’t be surprised to find primary neutral to-Earth voltage in

our buildings, because we go to great lengths to put it there.

ISOLATION OF NEUTRALS

The electrical system would be fine if the interconnection of the primary and secondary Neutrals

were removed. This would eliminate any voltage entering from the primary neutral. But this is

not permitted, since it would allow a potentially dangerous situation’s

Since a normally configured and properly wired distribution system almost never has neutral-to-

earth voltages in excess of 6/8 volts, it can be blocked by virtually creating open circuit

, “blocking” the neutral-to-earth voltage from entering a customer’s

Service. If the neutral-to-earth voltage is over 11 volts, either a fault or other failure has

occurred and it acts as a short circuit, connecting the neutral

For safety with the impedance in “shorted” mode.

ADDITIONAL EARTHING OF LITTLE HELP:

A typical response when encountering –off-site stray voltage is to drive an additional earthing

on the premises. Please consider the numerous earth stations along the multi-grounded

distribution system; the addition of even a few additional grounds is not likely to materially

reduce the voltage. In actuality, if the entire grounding complex were duplicated the voltage

would only be reduced by a magnitude of one-half.

The equipotential plane has been used in industries or other loads for protection within a small

confined area. It does nothing to eliminate source and corrects nothing in the connected loads

etc.

SOLUTION TO NEUTRAL TO EARTH VOLTAGE:

Neutral sources can be safely guarded against by installation of ISOLATION

TRANSFORMERS .This will cost much less than a single problem which can occur when

38

costly computerized equipment can be damaged.The use of ISOLATION TRANSFORMER is

very sound choice for a cost

–effective device which retains system safety and reliability while eliminating troublesome

neutral-to-earth “Stray Voltage”.

39

WARRANTY FOR THREE YEARS

1. TIME AND SCOPE OF WARRANTY

1.1 SBA POWER & EARTHING EQUIPMWNTS hereby warrants the equipment as per its

invoice No.__________ Date: ___________ to be Free from defective workmanship for a period

of THREE years from the date of shipment from SBA POWER & EARTHING EQUIPMWNTS.

Accident damage, misuse or normal wear shall not be construed to be a defect.

1.2 No provision of this warranty shall cover equipment which has been altered or modified

form from the original specifications to which it was manufactured.

1.3 SBA POWER & EARTHING EQUIPMWNTS reserves the right to make changes,

additions and or/or improvements in its products incurring any obligation to install them on its

products previously sold.

1.4 THE FORGOING WARRANTY IS EXCLUSIVE AND IS GIVEN AND ACCEPTED IN

LIEU OF ANY AND ALL OTHER WARRANTIES ,EXPRESSED OR

IMPLIED,INCLUDING WITHOUT LIMITATION THE IMPLIED WARRANTIES OF

MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.THE REMEDIES

OF THE BUYER SHALL BE LIMITED TO THOSE PROVIEDED HEREIN. IN NO EVENT

WILL THE SELLER BE LIABLE FOR COLLATERAL OR CONSEQUENTAL DAMAGE.

No person is authorized to assume on behalf of SBAPOWER any obligation oriability in

connection with the sale, warranty or service policy of any products manufactured and /or

marketed by SBA POWER & EARTHING EQUIPMWNTS beyond the warranty description on

the face hereof.

Gobind Ajwani

+91-9540520634(Office)

Email :info.sbapower@gmail.com

managerengineering@sbaapower.com

web site: www.sbapower.com

Manager -Engineering & Marketing

SBA Power & Earthing Equipments

Works: Main Dadri Road, Salarpur,Bhangel

Phase -II, Noida (U.P)