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ULUL’’s Future Approach to s Future Approach to Surge Protective DevicesSurge Protective Devices

byby

JoeJoe De De GregoriaGregoria, P.E., P.E.Primary Designated Engineer Primary Designated Engineer

Surge Protective DevicesSurge Protective DevicesUnderwriters Laboratories, IncUnderwriters Laboratories, Inc..

Thank you for giving me the opportunity to make this presentation today.

UL has been evaluating and Listing low voltage TVSS since the first edition of UL 1449 in 1985. Recently the 3rd edition of

UL 1449 was published and the transition from the 2nd to the 3rd edition will be the subject of this presentation.

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Past PracticePast Practice

22ndnd edition of UL 1449, edition of UL 1449, Standard for Transient Voltage Standard for Transient Voltage

Surge Suppressors (TVSS)Surge Suppressors (TVSS)

As many of you know the 2nd edition has been used to

evaluated TVSSs since 1996 and included many safety

enhancements from the first edition, notably the Abnormal

Overvoltage testing added to simulate a loss neutral

situation and to establish short circuit current ratings for

permanently wired TVSSs.

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2ND Edition

TVSS- Up to 600 V

Installation only on the load side of the service equipment overcurrent device -Article 285 of NFPA 70 (NEC)

One critical aspect of the 2nd edition was that it covered

TVSSs installed on the load side of the service equipment

OCP as limited in NEC article 285. The standard covered

cord connected, DPI and permanantly wired TVSSs rated

600V max.

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Past PracticePast Practice

Surge ArrestersSurge Arresters-- up to 600v up to 600v line or load sideline or load side--Article 280 of Article 280 of

NFPA 70 (NEC)NFPA 70 (NEC)

IEEE C62.1, Standard for IEEE C62.1, Standard for Metal Oxide Surge Arresters Metal Oxide Surge Arresters

for AC Power Circuitsfor AC Power Circuits

The 2nd edition did not cover Surge Arresters as covered in

NEC article 280. These devices were evaluated to IEEE

C62.1 Standard for Metal Oxide Surge Arresters for AC

Power Circuits. Surge Arresters were considered a

different breed of surge protective devices permitted to be

connected to the line side, as well as the load side, of the

service equipment OCP. These SPDs were typically

installed on the service drop and intended to protect

against lightning surges.The surge testing, as specified in

the the IEEE standard, was more rigorous than the second

edition of UL 1449, but did not include the abnormal

overvoltage testing and short circuit current testing that

was part of the 2nd edition.

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Past PracticePast PracticeLightning Protection SystemsLightning Protection Systems--UL UL

Master LabelMaster Label-- UL 96A (NFPA UL 96A (NFPA 780)780)

Required Surge Arresters or Required Surge Arresters or TVSS suitable for Lightning TVSS suitable for Lightning

Protection InstallationsProtection Installations

Because Surge Arresters were associated with lightning protection they were the only SPD permitted within UL Master Labeled Lightning Protection Installations. In 2004 UL announced a special TVSS for LPS that underwent additional testing and would be permitted within a UL96A installation.

Listed TVSS may be additionally marked “TVSS for LPS” if they:

1) Remain functional after the 10KA Surge Test as verified by the Measured Limiting Voltage

Test; and

2) Comply with the overvoltage test at 137.5% of the nominal system voltage.

RATIONALE

a) TVSS exhibit an acceptable “end of life” condition based on the Short Circuit Current and

Abnormal Overvoltage Tests of UL 1449.

b) They are limited to connection on the load side of the service disconnectovercurrent device.

c) TVSS would be additionally challenged via the 10KA Surge Test, followed by the Measured

Limiting Voltage Test, and the Overvoltage test.

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Future Practice3rd Edition UL1449,Standard for Surge Protective Devices

(October 2, 2006)

Incorporates TVSS and Surge Arresters up to 1000V in one

UL Standard – RenamedSurge Protective Devices

Spearheaded by the 3rd Edition task group, made up of several people sitting in this room today, through many painstaking hours of discussions, meetings and teleconferences developed the first draft of the 3rd edition for comment by the STP. After several rounds of STP comments and resolution meetings the final draft of the 3rd edition was sent out for ballot and consensus to accept the standard was achieved.

The 3rd edition was finally adopted the end of September, 2006 and was published October 2, 2006.

The striking difference between the 2nd and 3rd edition is a new name- Surge Protective Devices that incorporates TVSSs and Surge Arresters in one standard..

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In the 3rd Edition UL 1449

SPDs are designated as

Type 1, 2, 3 or 4

It incorporates the different SPDs (Surge Arresters, TVSS) in a single standard with Type designations established as 1, 2, 3 and 4 and based on installation location within the electrical distribution system.

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Type 1 SPDsType 1 SPDsPermanently connected Permanently connected Installed between the Installed between the

secondary of thesecondary of theservice transformer and the service transformer and the

line or load side of the service line or load side of the service OCPOCP

WWithoutithout external OCPexternal OCP

Type 1 – Permanently connected SPDs intended for installation between the secondary of the service transformer and the line or load side of the service disconnect equipment overcurrent device, including watt-hour meter socket enclosures and intended to be installed

without an external overcurrent protective device.

IEEE C62.34 Type SPDs

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Type 2 SPDsPermanently connected

Intended for installation on the load side of the

service equipment OCP

Includes SPDs located at the branch panel.

Type 2 – Permanently connected SPDs intended for installation on the load side of the service disconnect equipment overcurrent device; including SPDs located at the branch panel.

IEEE C62.62 Type SPDs.

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Type 3 SPDsPoint of utilization SPDs

Installed 10 meters (IEEE C62.41) from the electrical

service panel

Includes cord connected,direct plug-in, receptacle type

and SPDs installed at the equipment being protected.

Type 3 – Point of utilization SPDs, installed at a minimum conductor length of 10 meters (30feet) from the electrical service panel to the point of utilization, for example cord connected,

direct plug-in, receptacle type and SPDs installed at the utilization equipment being protected.

See marking in 65.2. The distance (10 meters) is exclusive of conductors provided with or used to attach SPDs.

The 10 meters (30 feet) comes from IEEEC62.41 where location A, outlets and long branch circuits, shall be more than 10 meters from category B, Service Entrance. 3rd

edition testing for Type1 and 2 SPDs (location B) is different from the testing for Type 3 SPDs (location A).

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Type 4 SPDs

Component SPDs, including discrete components as well as

component assemblies.

Type 4 SPD can be a single discrete MOV or a module/assembly consisting of different SPD components, including multiple MOVs, GDT, air gap, SAD, etc. intended to be installed with an overall complete SPD.

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33rdrd Edition TestingEdition Testing

All SPD TypesAll SPD Types6KV/3KA Combination wave for 6KV/3KA Combination wave for

Voltage Protection Voltage Protection Rating(previously SVR)Rating(previously SVR)

2nd edition MLV testing to establish what was called the SVR was 6KV/500A combination wave.

3rd Edition testing for all SPD Types is at 6KV/3KA combination waveform representing the high level of surge exposure (IEEE C62.41.)

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33rdrd Edition TestingEdition TestingType 1 and 2 SPDsType 1 and 2 SPDs

Nominal Discharge Current,In,Nominal Discharge Current,In,15 surges, 8x20us current 15 surges, 8x20us current

wave impressed through the wave impressed through the SPD SPD

Similar To IEC 61643Similar To IEC 61643

After the MLV testing the same samples of Type 1 and 2 SPDs, will be subjected to an 8x20 us surge current impressed through the SPD, similar to the In testing in IEC 61643.

38.7.1 The manufacturer shall specify (declare) the value of the Nominal Discharge Current (In) to which the sample will be tested. The value of the Nominal Discharge Current (In) selected by the manufacturer shall be: 10 kA or 20 kA for Type 1 SPDs and 3 kA, 5 kA, 10 kA or 20 kA for Type 2 SPDs. The surge generator shall be adjusted to ensure that the value of In (selected by the manufacturer) is impressed through the SPD.

38.1. The same three representative devices that were subjected to the 6 kV/3 kA combination wave in the Voltage Protection Rating Test, shall then be subjected to fifteen (15) x 8/20 short circuit current surges, per mode. The surges are to be applied at the application points specified in 38.4.

38.7.3 During the application of these surges the samples are unenergized. Surges shall be applied in three groups of five surges. Within 1 second after the application of each surge, the manufacturer’s

specified (declared) MCOV shall be applied for 60 seconds ±15 seconds. After each group of 5 surges, the sample shall rest for 30 minutes ±5 minutes. After the 15th surge, the MCOV shall be re-applied for at least 15 minutes.

.

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Type 1 SPDType 1 SPDNominal Discharge CurrentNominal Discharge Current

10KA or 20 KA10KA or 20 KAto comply with lightning to comply with lightning

protection (UL96A, NFPA780)protection (UL96A, NFPA780)

Type 2 SPDType 2 SPDIn = 3KA, 5KA, 10KA or 20 KAIn = 3KA, 5KA, 10KA or 20 KA

Type 1 SPDs can be rated and tested for 10 or 20 KA corresponding to the requirements in NFPA 780, Standard for the Installation of Lightning Protection Systems and eventually UL 96A (Master Labeled LPS).

Type 2 SPDs can be rated and tested at 3, 5, 10 or 20 KA

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Type 3 SPDType 3 SPD

Operating Duty Cycle Operating Duty Cycle 15 Surges, Combination 15 Surges, Combination

wave, at 6KV/3KA, wave, at 6KV/3KA,

After the MLV for the VPR the same samples of Type 3 SPDs are subjected to 15 surges of 6KV/3KA combination waveform similar to Class III SPDS in IEC 61643.

38.8 Operating Duty Cycle Test – For Type 3 SPDs

38.8.1 Type 3 SPDs or Type 4 SPDs (intended for locations in which a Type 3 SPD may be installed),

shall be energized and subjected to the Operating Duty Cycle Test while connected to a rated power

source. The same three representative devices that were subjected to the 6 kV/3 kA Combination Wave

Surge, shall be subjected to fifteen (15) x 6 kV/3 kA combination wave surges, per mode, as specified in

Table 38.1, applied at the application points specified in 38.4. Eight (8) surges shall be positive polarity at

a phase angle of 90 (+0, -15) degrees and 7 shall be negative polarity at a phase angle of 90 (+0, -15)

degrees. The surges are to be conducted in succession with a maximum 60 second period between each

surge.

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Type 4 SPDType 4 SPD

Testing based on application Testing based on application as Type 1, 2 or 3 SPDas Type 1, 2 or 3 SPD

Type 4 SPDs are tested based on their intended application as Type 1, 2, or 3 SPDs.

Type 4 SPDs intended for other than SPD applications (appliances, etc.) may be tested at

the manufacturer’s stated rating.

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Voltage Protection Voltage Protection RatingRating

Repeated after In or Repeated after In or Operating Duty Cycle Operating Duty Cycle

Shall not deviate by more Shall not deviate by more than 10% from initial VPRthan 10% from initial VPR

The same 3 samples that were subjected to In testing or Operating Duty Cycle testing are again subjected to the VPR test. 3 surges at 6KV/3KA, combination waveform.

VPR shall not deviate by more than 10% from the initial VPR.

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Operational VoltageOperational Voltage

115% of rated SPD voltage115% of rated SPD voltage

Following the repeated VPR tests the same samples shall be subjected to an overvolate at 115% of rated voltage.

Following the repeated VPL VPR Test (6 kV/3 kA Combination Wave Surge), the SPD shall be subjected to an overvoltage of 115 percent of the rated supply voltage (to simulate the upper tolerance of the supply voltage) for 30 minutes. The SPD must remain operational and shall meet the pass criteria as specified in 39.5. For SPDs intended for use on ungrounded systems, impedance grounded systems, or corner grounded delta systems, the line-to-ground modes shall be tested at 115% of the rated line-to-line voltage.

39.5 Pass Criteria – During and following the overvoltage tests the following conditions shall not result:

a) Emission of flame, molten metal, glowing or flaming particles through any openings (preexisting

or created as a result of the test) in the product.

b) Charring, glowing, or flaming of the supporting surface, tissue paper, or cheesecloth.

c) Ignition of the enclosure.

d) Creation of any openings in the enclosure that results in accessibility of live parts, when

e) Supplementary protective devices, internal or external to the SPD, opening.

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Current TestingCurrent Testing

Type 1 and 2 SPDType 1 and 2 SPDShort Circuit Testing (forced Short Circuit Testing (forced

conduction of SPD) and Short conduction of SPD) and Short Circuit Current Rating (NEC Circuit Current Rating (NEC

requirement)requirement)

Type 1 and 2 SPDs are subjected to this test at the SCCR of the SPD chosen by the manufacturer(5KA- 200KA).

Type 1 SPDs are tested with no series OCP unless provided as part of the overall equipment.

Type 2 can be tested in series with a specific type of OCP, circuit breaker or fuse that will be marked on the SPD.

SPDs are subjected to twice the rated voltsge to force conduction or the following options are applied:Exception: For permanently connected (Type 1 and Type 2SPDs) devices that do not conduct current (beyond leakage current) when subjected to the test, any one of the following options, or any combination thereof, shall be implemented and the test described in 40.2.1 repeated:a) Short out any voltage switching components with solid wire that shall not open during this

test;

b) Increase the test voltage above the values in 40.1 until operation occurs; or

c) Use lower voltage rated (MCOV shall be in a range of 60 – 80 percent of the nominal

system voltage) nonlinear voltage limiting components from the same manufacturer and product family with identical chemical composition. Test the lower voltage rated component at the

maximum voltage specified in 40.1.

d) For voltage switching-type SPDs, a combination waveform surge shall be applied on the ACpower source at a voltage level to turn on the SPD.

Pass criteria – During and following the tests described in 40.2.1 – 40.4.2, the following

conditions shall not result:

a) Emission of flame, molten metal, glowing or flaming particles through any openings (preexisting

or created as a result of the test) in the product.

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Intermediate Current Level Intermediate Current Level TestingTesting

Type 1 and Type 2 SPDType 1 and Type 2 SPD1KA, 500A, 100A1KA, 500A, 100A

Type 3 SPDType 3 SPD50A, 150A and 1kA or 2KA50A, 150A and 1kA or 2KA

Type 1 and 2 SPD are subjected to twice rated voltage to force conduction or the following options are applied:

For permanently connected devices that do not conduct current (beyond leakage current) nor

exhibit any conditions described in 40.1.11 when subjected to the test, any one of the following options,

or any combination thereof, shall be implemented and the test described in 40.3.1repeated:

a) Short out any voltage switching components with solid wire that shall not open during this

test;

b) Increase the test voltage above the values in 40.1 until operation occurs; or

c) Use lower voltage rated (MCOV shall be in a range of 60 - 80 percent of the nominal system voltage) nonlinear voltage limiting components from the same manufacturer and product family with identical chemical composition. Test the lower voltage rated component at the maximum

voltage specified in 40.1.

d) For voltage switching-type SPDs, a combination waveform surge shall be applied on the AC power source at a voltage level to turn on the SPD.Type 3 are connected to twice rated voltage for 7 hours.

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Limited CurrentLimited Current

Type 1 or 2 SPDType 1 or 2 SPD10A, 5A, 2.5A, .5A10A, 5A, 2.5A, .5A

Type 3 SPDType 3 SPD5A, 2.5A, .5A, .125A5A, 2.5A, .5A, .125A

Four previously untested representative devices of the SPD for each combination of conductor pairs that were tested in accordance with Section 38, are to be connected to an ac power supply having

an open circuit voltage equal to the test voltage specified in Table 40.1. The power supply is to incorporate a series variable resistor that can be adjusted to obtain the short-circuit current (Isc) specified below. See

adjusted such that Isc equals the values specified in Table 40.6. The four representative devices are to be energized for 7 hours,or until current to, or temperatures within the SPD attain equilibrium, or until the

SPD becomes disconnected from the ac supply (due, for example, to open circuiting of a thermal or overcurrent protective device).

Type 4 SPDs shall be tested based on the intended application.

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SPD MarkingSPD Marking

SPD TypeSPD TypeElectrical RatingsElectrical Ratings

VPRVPRIn,MCOV for Types 1 and 2In,MCOV for Types 1 and 2

SCCR for Types 1 and 2SCCR for Types 1 and 2

An SPD shall be plainly and permanently marked with the following information:

a) The name of the manufacturer or other descriptive marking by which the organization

responsible for the product can be identified;

b) A distinctive catalog number or equivalent designation;

c) SPD Type (1,2,3). Type 4 (assembly or module) SPDs shall be marked based on the

performed testing for Type 1, 2 or 3 applications;

d) Electrical ratings per Section 64;

e) Nominal Discharge Current (In) Rating (64.1);

f) Maximum Continuous Operating Voltage Rating (MCOV) (64.1);

g) Voltage Protection Rating (VPR) (64.2)

h) Date or period of manufacture not exceeding any three consecutive months which is able to

be abbreviated or in a nationally accepted code;

i) Short Circuit Current Rating (SCCR) (65.11 and 65.11);

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2008 NEC2008 NEC

Article 285 will reflect 3Article 285 will reflect 3rdrd

Edition UL 1449 Type Edition UL 1449 Type designationsdesignations

Article 280 will cover Surge Article 280 will cover Surge Arresters over 1KV evaluated Arresters over 1KV evaluated

to IEEE C62.11to IEEE C62.11

Proposals for 2008 NEC

Article 285 will replace the term TVSS with SPD up to 1KV and include SPD Types.

Article 100 (definitions) will include definitions of SPD Types 1, 2, 3 and 4.

Article 280 will cover Surge Arresters over 1KV evaluated by UL using IEEE C62.11-1999.

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2007 NFPA 7802007 NFPA 780

Will reflect 3Will reflect 3rdrd edition UL 1449 edition UL 1449 In ratings for Type1 and 2 In ratings for Type1 and 2

SPDSPD

2007 NFPA780 will specify In requirements for SPDs in lightning protection installations that correspond to the In levels in the 3rd edition of UL 1449.

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Where do we go from here?Where do we go from here?

File Review for all Certified File Review for all Certified TVSS and Surge Arresters for TVSS and Surge Arresters for compliance with the 3compliance with the 3rdrd Edition Edition

of UL 1449of UL 1449

36 month effective date.

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Next Revision CycleNext Revision Cycle

Include the Verification of Include the Verification of Discrete Component Discrete Component

Parameters in the 3Parameters in the 3rdrd Edition Edition of UL 1449 to Facilitate the of UL 1449 to Facilitate the Interchangeability of Interchangeability of MOVsMOVs