S&C Source-TransferPMH Pad-Mounted GearOutdoor Distribution (14.4 kv and 25 kv)

With Micro-ATTM Control

... ---- -.,

-

New Publielllion 0'991

~!ii--------DESCRIPTIVE BULLETIN 663A.30~ S&C ELECTRIC COMPANY· Chicago Page 1 of 20.::II S&C ELECTRIC CANADA l TO.• Toronto September 23,1991

sac Source-Transfer PMH Pad-Mounted Gear IOutdoor Distribution (14.4 kv and 25 kv)

With Micro-AT'" Control

I.;;;G.;;;EN.;.;;E;;.;R;.;;AL;..... Isac Source-Transfer PMH Pad-Mounted Gear ••• totally self-containedswitching and protection packages that provide fully automatic sourcetransfer and fault protection for distribution systems serving small- tomedium-sized industrial, commercial, and institutional complexes.

In the past, many small- to medium-sized installationsdesiring automatic source transfer for critical loads hadto choose between overhead automatic transferschemes and power-operated metal-enclosed switch­gear. Overhead transCer schemes, however, requireconsiderable equipment and space, compromising theaesthetics of the installation, and are vulnerable to thevarious outages typically associated with overheadequipment. And the simple medium-voltage systems ofthese small industrial, commercial, and institutionalinstallations often do not require the use of metal­enclosed switchgear with its additional constructionfeatures, range of ratings, and design and operatingflexibility. For these locations, it is therefore difficultto justify power-operated metal-enclosed switchgear,

COMPARTMENT-3 COMPARTMENT-4

so~ _~__ n nnmnmm

~ - --- --- ---- ----~--

COMPARTMENT-2 COMPARTMENT·'

PMH-6 Model

with its premium, solely to provide automatic sourcetransfer. Accordingly, for these installations, users oftenhad to choose manual switching equipment such asS&C's Manual PMH Pad-Mounted Gear.

Today, there's a better alternative-S&C Source­Transfer PMH Pad-Mounted Gear. S&C has solved theaesthetic, reliability, and economic problems by offeringtwo Source-Transfer PMH Models. These compact, low­profile, pad-mounted packages achieve the outstandingreliability demanded by automatic source-transferapplications through the use of advanced electronicsand field proven components in uniquely rugged,corrosion-resistant enclosures. And through pre­engineering of standardized designs suited to repetitivemanufacture, plus a commitment to capital equipment

COMPARTMENT·3 COMPARTMENT-4

v V V5 5 5

COMPARTMENT-2 COMPARTMENT·'

PMH-9 Model

Figure'. Circuli configurations of the two models of SAC Source-Transfer Pad·Mounfed Gear.

663A.30 DESCRIPTIVE BULLETINPage 2 of 20September 23, 1991

S&C ELECTRIC COMPANY. Chicago IiIIIS&C ELECTRIC CANADA LTD.• Toronto IfIl!I

IGENERAL - Continued

to maximize manufacturing efficiencies, these top­quality packages are available at a cost suited to theeconomics of smaller automatic souTce-transferappLicaLions. Source-Transfer PMH Pad~Mounted Gearis designed with an attention to detail available onlyfrom S&C. with its nearly 50 years of experience inmanufacturiJ}8 metal-enclosed gear.

S&C Source-Transfer PMH Pad-Mounted Gearprovides both fault protection and automatic primary­selective service on underground distribution systemsfor small- to medium-sized critical loads requiring ahigh degree ofservice continuity. These source-transfermodels are completely self-contained switching andprotection packages. Each model has built-in voltagesensing, control power, automatic controls, interrupterswitches, slored-energy switch operatol'"S, and fusemountings. They are available in two basic circuitconfigurations (see Figure 1) Lhat provide reliable andflexible three-pole automated switching of sourcecircuits rated up through 600 amperes, and single-poleswitching and fault protection for either one or twoload feeders rated up through 400 amperes.

Source-Transfer PrMI Models are completely factory­assembled, thoroughly checked and tested. and readyfor installation. There is no external wiring or controlpower required. InstaUation is easy and straightfor­ward-just connect the power cables and program theoperating characteristics and parameters, and the gearis ready for service-minimizing Lhe installed cost.

S&C Voltage Sensors, three for each source, provideall the voltage inputs required by the source-transferscheme. These devices produce an output voltage thatis the sensing input to the Micro-AT Source-TransferControl. They also supply control power for operationof the source-transfer control and stored-energy switchoperators.

The S&C Micro-AT Source-Transfer Control contin­uously monitors the output of the voltage sensors todetermine the condition of the two power sourcesserving the gear. If the source serving the load fails,the control initiates switching to transfer to the alter­nate source, restoring power to the load. This advanced,

Imicroprocessor·based, electronic control is fieldprogrammable to permit the implementation of source­transfer applications that maximize power service tothe loads, while conforming to the serving utility'ssystem switching practices. It offers field selection ofeither power source as the preferred, lets you selectautomatic or manual return to the preferred sourcewhcn normal voltage returns, and allows eitherparalleling or nonparalleling of sources when in theautomatic return mode. The source-transfer controlalso features field adjustable loss-of-source and return·of-source voltage levels, as well as adjustable lime delaysfor coordination.

S&C Mini-Ruple'" Switches are three-pole group­operated interrupter switches specilically designed tohandle all live-switching duties on incoming sourcecircuits, including full-load and associated transformer­magnetizing and cable-charging currents, with noexternal arc or flame. They afford maximum operatingflexibility because of their exceptional two-time duty­cyclc fault-closing ratings-22,4oo amperes rms asym·metrical at 14.4 kv, 20,000 amperes rms asymmetricalat 25 kv. These fault-closing ratings represent theavailable fault currents into which the switches canbe closed twice, remaining operable and able to carryand interrupt rated currents. This exceptional abilitypermits quick restoration of service following a fault­without the need for an extended outage for replace­ment of switch parts or for temporary restoration ofservice through an alternate switch until replacementparts can be obtained.

These outstanding duty-cycle fault-closing ratingsmake S&C Mini-Rupters superior to ordjnary switcheswith simple "fault-closing~or "make-and-Iatch" ratingswhich, following an initial fault-closing operation, offerno assurance of an ability to subsequently carry orinterrupt rated current-much less any expectation oftolerating a second fault closing. The ability to openfollowing a fault-closing operation is of especialimportance where automatic control is utilized forprimary-selective service.

SIC ELeCTRIC COMPANY. ChicagoSIC ELeCTRIC CANADA l TO.• Toronto

DESCRIPTIVE BULLETIN 663A·30Page 3 of 20

September 23, 1991

S&C Source-Transfer PMH Pad-Mounted Gear IOutdoor Distribution (14.4 kv and 25 kV)

With Micro-Aroo Control

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Stored-energy switch operators provide high-speedpower operation of the Mini-Rupter Switches. Theoperators incorporate a quick-make quick-breakmechanism that is motor-charged, and opens and closesthe Mini-Rupter swiftly and positively when solenoidtripped in response to signals initiated by the source­transfer control, or when manually tripped using eitherpushbuttons or the dual-purpose manual handle. Thishigh-speed operation contributes to Mini-Rupter's duty­cycle fault-closing ratings and reduces the period oftime the load is without power-transfer is achievedin 10 cycles plus any intentional time delay forcoordination.

Load feeders are switched and protected using S&CPower Fuses with Uni-Rupter'· (accommodating achoice of S&C Type SML-20 or SML-4Z Power Fuses,Fault Fiterl8l Electronic Power Fuses, or a variety ofsingle-barrel current-limiting fuses). With S&C's time­tested SML Power Fuses, you can select from a widevariety of ampere ratings and time-current charac­teristics (TeCs) to achieve close fusing for maximumprotection and optimum coordination. These TCes areprecise, with only 10% total tolerance in melting current,compared to the 20'X; tolerance of many fuses (20% and40% respectively, in terms of time). And the design andconstruction features of the fusible elements assurethat SML Power Fuses will conform to their TCCs notonly initially, but on a sustained basis. _. neither age,corrosion, vibration, nor surges that heat the elementnearly to the severing point will affect the character­istics of S&C SML Power Fuses.

S&C Fault Fiter Blectronic Power Fuses combine aninnovative high-technology electronic control modulewith a unique interrupting module to solve difficultprotection and coordination applications. The controlmodule incorporates a current transformer and

electronic circuitry to provide current sensing and theTCC of the fuse, as well as the energy to initiate theinterrupting process. By using electronics, Fault Fiteroffers an unprecedented variety of unique TCes thatprovide superior protection and precise coordinationin a wide range of applications. Moreover, since thefusible elements do not determine the TCC of the fuse,Fault Fiter is not susceptible to the protection vagariesofother types of fuses where the elements are subjectedto load cycling or repeated current surges that canalter the TeC.

S&C's Uni·Rupter lets you perform single-pole liveswitching of fuses on transformers, lines, and cables,with no external an.: or flame. Uni-Rupter can carryand interrupt load currents up to and including theemergency peak-load capability of the fuse. Further­more, S&C Power Fuses with Uni-Rupter have a one­time duty-cycle fault-closing capability equal to theshort-circuit rating of the pad-mounted gear and a two­time capability of 13,000 amperes rms asymmetrical.The duty-cycle fault-closing capability is the level ofavailable fault current into which the fuse can be closedthe specified number of times with the Uni-Rupterremaining operable and able to carry and interruptcurrents up to the emergency peak-load capabilitiesof the fuse.

SpecifyS&CSource-Transfer PMH Pad-Mounted Gearfor all your small- to medium-sized critical loadsrequiring primary-selective service. It is the simple andeconomical solution to automatic source-transferapplication problems on your power distributionsystem. The gear is a totally self-contained switchingand protection package ... it has the features you needto achieve a high degree of service reliability andoperating flexibility and provides the ultimate ininstallation and operation simplicity.

663A.30 DESCRIPTIVE BULLETINPage 4 of 20September 23, 1991

S&C ELECTRIC COMPANY. ChIcago IBaS&C ELECTRIC CANADA lTD.• Toronto ~

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The S&C Source-Transfer Pad-Mounted Gear picturedbelow (8t left) and diagrammed at right provides hlgh·speedautomatic source tranlfer plus switchIng and protection fortwo 2500 kV8, three-phase 12.47 kv/480 y transformerssal'Ylng a medium-sized Industrial plant.

Figure 2. S&C Sourcft-Transfer Pad-Mounted Gear provides fully automatic source transfer for a recently constructed industrialplant.

5&C ELECTRIC COMPANY. ChIcagoS&C ELECTRIC CANADA l TO.• Toronto

DESCRIPTIVE BULLETIN 663A·30Page 5 of 20

September 23, 1991

S&C Source-Transfer PMH Pad-Mounted Gear IOutdoor Distribution (14.4 kv and 25 kv)

With Micro-AT"· Control

I~A;;,P.:.P,:;L;,;;IC::;A;.:T.:.IO;:.N:':"' ....JI

S&C's fully automatic Source-Transfer PMH Pad-Mounted Gear bringshigh-speed source transfer to your small- to medium-sized critical loadsrequiring a high degree of service continuity.

Figure 3. Source-transfer pad-mounted gear applied toprovide automatic primary-selective service lor critical loadsserved from two radial feeders. Either of the two sourcesmay be designated 8S the preferred source, the other sourcethen serves as the alternate source.

Source 2

50

Radialfeeders

5TC50

SoUlce 1

the hold return mode, if the alternate source fails andthe preferred source has been restored, the switchgearwill automatically retransfer to the preferred source.If desired, the source-transfer control can be perma­nently set at the factory for !wid return mode.

In the automatic return mode, you can select eitherapen transiticm or closed transition for automaticretransfer to the preferred source. In apen transition­which prevents paralleling the power sources-thealternate-source switch opens prior to closing of thepreferred-source switch ... there is only a momentaryinterruption of service to the load. With closedtransition retransfer-selected when it is permissibleto parallel the two sources-there is no interruptionof service to the load as the alternate-source switchopens only after the preferred-source switch has closed.

Certain loads such as hospitals, stadiums, auditoriums,pumping stations, and shopping malls require a highdegree of service continuity. This can be achieved byduplicating facilities such as power sources, switchgear,or transformers. System reliability studies indicate thatthe power sources constitute the major cause ofselViceinterruptions due to extensive exposure to suchphenomena as lightning, wind, and ice, and also to dig­ins and equipment failure. Accordingly, users withcritical loads typically first provide primary-selectivesel'lice to ensure continuity of the medium-voltagesupply before considering other systems that attemptto minimize interruptions due to problems with loadtransformers or transformer-secondary equipment.

Primary-selective service can be provided from tworadial feeders or from double-circuit looped-primaryfceders. Primary-selective service from two radialfeeders is an inexpensive, simple, and direct schemethat is used to serve relatively small, isolated criticalloads. Use of radial circuits facilitates quick locationand isolation of a faulted feeder. Figure 3 illustratessource-transfer pad-mounted gear applied to provideprimary-selective service from two radial feeders. Theunit diagrammed is a PMH-9 Model. A source-transfercontrol and interrupter switches driven by stored­energy switch operators provide fully automatic two­way source transfer with the ability to connect eitherof the two radial feeders to the pad-mounted gear'smain bus. Each load-feeder circuit supplies medium­voltage power to and protects a single remotetransformer.

Under normal operating conditions, one switch (forthe preferred source) is closed; the other switch (forthe alternate source) is open with its associated circuitavailable as a standby. The source-transfer controlmonitors the condition of both power sources andinitiates automatic switching when the preferred­source voltage has been lost, or reduced to a prede­termined level, for a period of time sufficient to confirmthat the loss is not transient. The switch associatedwith the preferred source is automatically opened andthe alternate-source switch is then automaticallyclosed, restoring power to the load.

fuo-way source transfer provides for automaticretransfer to the preferred source when normal voltagereturns for a preset time (automatic return mode) ...or for selection of manual retransfer to the preferredsource at a convenient time (hold return mode). In

663A.30 DESCRIPTIVE BULLETINPage 6 of 20September 23, 1991

S&C ELECTRIC COMPANY. ChIcago I9IJIS&C ELECTRIC CANADA l TO•• Toronto IIII:!t

IAPPLICATION - Continued IIf desired, the source-transfer control can be perma­nently set at the factory for open-transition auwmaticretransfer. And for applications where automatic andmanual parallelingofsources is to be denied completely,an optional antiparalleling device is available.

A more complex scheme used to provide primary­selective service for an extensive system ofcritical loadsis illustrated in Figure 4. This scheme is used whenproviding service to several small- to medium-sizedinstallations in the same locality or to one largeinstallation with widely dispersed loads. Under normaloperating conditions, each source serves as the

preferred source for at least. one unit of source-transfergear and as the alternate source for the oLher(s). SinceaU source-transfer controls permit field selection ofeither source as preferred, you have the nexibility todevelop a more evenly loaded system and to reducethe likelihood of causing an intolerable systemdisturbance when a source transfer occurs.

To further complement service continuity andoperating nexibility, both ends of the circuits depictedin Figure 4 could be connected through sectionalizingswitches to the source circuits. This creates a double­circuit looped-primary system.

Source 1

Double-circuitprimary leeders

so []ILl soso~ so

Figure 4. Widely dispersed loads requiring a high degree of service contlnully can be served from double·circult primaryfeeders, as ahown above, with source-transfer pad-mounted gear providing automatIc swItching of aource circuits for prlmary­selective service. The load-feeder circuIts In each unIt of source-transfer gear provide switching and protecllon for cable­connected loads, one 01 which conalsts of three single-phase loads.

DESCRIPTIVE BULLETIN 663A·30SIC ELECTRIC COMPANY. ChicagoSIC ELECTRIC CANADA LTD.• Toronto

Page 7 of 20September 23, 1991

sac Source-Transfer PMH Pad-Mounted Gear IOutdoor Distribution (14.4 kv and 25 kv)

With Micro-Ar'" Control

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An extensive power distribution system will fre­quently include critical loads requiring automaticprimary-selective service interspersed with loads thatcan tolerate the delay associated with manual switchingto restore power in the event of an interruption. Suchsystems may be implemented with combinations ofsource-transfer and manual pad-mounted gear.

The system of double-circuit looped-primary feedersshown in Figure 5 serves dispersed installationsrequiring different degrees of power availability. Threeinstallations on this system have been deemed criticalloads requiring a high degree of service continuity. Forthese installations, source-transfer pad-mounted gearis applied to provide primary-selective selVice from thedouble-circuit looped-primary feeders. Four manualunits of pad-mounted gear-two on each looped­primary feeder-are used to serve installations that do

not require primary-selective selVice, and to section­alize the loop. Two other manual units, each containingonly an interrupter switch, are utilized to switch theends of the looped-primary feeders.

Under normal conditions, one switch in the manualunit of pad-mounted gear located near the center ofeach loop is open as shown in the diagram and loadsserved bysource-transfer units receive power from theirpreferred source. Should power to either loop be lost,the control in each source-transfer unit on the affectedcircuit will initiate an automatic transfer operation torestore power to the associated critical loads. The loadsserved by the manual units on the affected circuit willbe without power until either the source voltage isrestored or, in the case of a fault in the loop, manualswitching operations are performed to isolate thefaulted section and restore selVice.

663A.30 DESCRIPTIVE BULLETINPage 8 of 20September 23, 1991

S&C ELECTRIC COMPANY. Chicago ~SIC ELECTRIC CANADA LTO•• Toronto g}I

IAPPLICATION - Continued I

,,' ,SOurce 2

-Jl-R ff.[ ]

H: ~

-J:[~ \-. , r L

L:::::T~

'-- :1-I

.-~ ~Double-circuit :H

/' / looped-primary feeder. ti tt -

~I/- ;; -'-

./I.JI t:l~t-l i--

./. -11N.O. -r-

-~i:f<>."l,

so.,

(

Figure S. On medIum-voltage dlstribulion 'ystems, pad-mounted gear Is used to serve Widely dIspersed loads requiringdifferent degrees of seAlce continuity. Sourc...transfer gear served from double--circult looped-primary 'eedert providesprimary-Ielective service to crillcalloads. Manual gear serves to sectlonaliz. each loop and to provide service to Installallonsthat do not require prlmary-selecllve service.

SIC ELECTRIC COMPANY. ChicagoSIC ELECTRIC CANADA LTO.• Toronto

DESCRIPTIVE BULLETIN 663A·30Page 9 of 20

September 23, 1991

sac Source-Transfer PMH Pad-Mounted GearOutdoor Distribution (14.4 kv and 25 kv)

With Micro-AT™ Control

I..A_p_p_L_I_C_A_T_lo_N__c_o_n_t_in_u_e_d ......1

Source-transfer pad-mounted gear may also fmdapplication on in-plant industrial, commercial, andinstitutional installations in combination with metal­enclosed switchgear. A system used to serve anindustrial complex having a geographically isolatedcritical load is illustrated in Figure 6. In the system

depicted, two source circuits provide medium-voltagepower to a nine-bay lineup of power-operated metal­enclosed switchgear consisting of two entrance bays,a tie-switch bay, and six feeder bays. The switchgearis configured in a split-bus arrangement to provideprimary-selective service to the loads served by each

--------------------.....--------------- Source 1

-----------~....------_4-------------- Source 2

TT

Preferredfeeder

Alternatefeeder

TT

Figure 6. Source-transfer pad-mounted gear is used in conjunction with metal-enclosed switchgear to serve geographicallyisolated critical loads.

663A.30 DESCRIPTIVE BULLETINPage 10 of 20September 23, 1991

S&C ELECTRIC COMPANY. Chicago YIaS&C ELECTRIC CANADA LTO.• Toronto m

I..A_p_p_L_'_C_A_T_'o_N__c_o_n_t_in_u_e_d 1

feeder bay. Four of the feeder bays provide switchingand protection for cable-connected transformers. Theremain\ng two feeders serve as the preferred andalternate sources for a unit of source-transfer pad­mounted gear, which provides primary-selective servicefor a remote critical facility on the complex.

For faults on the source circuits, the source-transfercontrol in the switchgear lineup is programmed so thattransfer occurs before automatic switching is initiatedin the source-transfer pad-mounted gear. And for faultson the preferred feeder cable, the pad-mounted gearwill transfer to the alternate cable. The use of metal­enclosed switchgear provides the ability to switch toa second utility incoming source in the event one islost. Placing the source-transfer pad-mounted gearclose to the critical load allows recovery in the eventof a cable fault. This capability is particularly usefulin the case of long cable runs.

The source-transfer controls of the metal-enclosedswitchgear and source-transfer pad-mounted gear canbe permanently set at the factory for open transitionto prevent the possibility of an automatic retransferthat would parallel the two utility sources. In addition,the pad-mounted gear can be equipped with amechanical antiparalleling device to prevent manualand automatic operations that would result in bothswitches being closed. Use of such a device wouldeliminate the possibility of backfeeding a bus sectionin the metal-enclosed switchgear through the pad­mounted unit and inadvertently paralleling the utilitysources.

Other Considerations forPrimary-Selective SystemsIn developing power distribution systems that provideautomatic primary-selective service, considerationshould be given to the addition of other features thatprovide protection against certain special conditionsthat may occur on the system. For three-phase loads,in particular, consideration should be given to providinga scheme that initiates a source transfer in the eventan open-phase condition occurs on one or two phasesof a source circuit energized at the same voltage asthe pad-mounted gear. It would also be desirable toinclude a lockout scheme to prevent automaticswitching operations that would transfer an overcur-

rent condition to an otherwise unfaulted source circuit.To protect against these special conditions, source­transfer pad-mounted gear should be equipped withan unbalance detection scheme and overcurrent­lockout feature. These circuits can be incorporated inthe source-transfer control.

Optional Unbalance Detection. This feature initiatesautomatic transfer in the event one or two phases ofa source are opened as a result of single-pole switching,broken conductors, blown fuses, or equipment malfunc­tions. Such a feature is applied where it is desirableto protect three-phase loads from all source-side open­phase conditions. The unique scheme used in S&C'ssource-transfer control continuously develops andmonitors the negative-sequence voltage of each sourceto detect the three-phase voltage unbalance that occursas a result of an open-phase condition. This protectionscheme, unlike methods that depend upon currentsensing, is not affected by unbalanced load currentsor circuit load levels. And unlike simple methodsemploying voltage-magnitude sensing, this scheme isnot defeated when voltage backfeed results in normal­magnitude voltage appearing on the opened phases,such as can occur on a delta-connected transformerwhen fuses on two phases operate.

Optional Overcurrent Lockout (with remote reset ifspecified) may be included in the source-transfercontrol to prevent a transfer operation that would closea source switch into a fault, thereby avoiding intro­duction of a disturbance on the utility's distributionsystem.

To implement this scheme, three-phase currentsensing is employed to detect overcurrents that involveone or more phases. For faults producing overcurrentsthat are cleared by source-side protective devices, theresulting prolonged loss of voltage will cause theassociated source interrupter switch to open. At thesame time, a lockout mode is set up in the source­transfer control, so that the alternate-source switchoperator will not automatically close its switch intothe fault. For faults producing overcurrents that arecleared by feeder fuses, there is no prolonged loss ofvoltage and, hence, the control does not initiate anyswitching operations.

S&C ELECTRIC COMPANY • ChicagoS&C ELECTRIC CANADA LTD.• Toronto

DESCRIPTIVE BULLETIN 663A·30Page 11 of 20

September 23, 1991

sac Source-Transfer PMH Pad-Mounted Gear IOutdoor Distribution (14.4 kv and 25 kv)

With Micro-AT'- Control

I.,;C;.;O;.;M;;;P..;O;.;N~E;;;N~T;.;S;... ....IEnhance service continuity and improve operating flexibility for yourcritical loads with these built-in features •••

• IJUlulated root--no-drip· compoundon underside of roof guards againstformation of condensation that coulddrip onto energized pans.

• GI&88-reinton::ed polyester barriersdo not absorb moisture, will not warp.And they're track-resistant andflame-retardant.

e Segregated ci.rcuits-full-lcngthsteelbarriers separate side-by-side com·partments. Fiberglass-reinforcedpolyester barriers isolate the tic-bus,separating front compartments fromrear compartments, and serve asinterphase and end barriers (whererequired to achieve BIL ratings) forswitches and fuses.

.. Cypoxr', S&C's cydoaliphatic epoxyresin system, insulates aU lhoe partsfrom ground.

e Compartment- and pbase-Identl­ncalion labels.e Aluminum bus connections (insideenclosure) are bolted at a uniformtorque of50 ft-Ibs; two spring washersper bolt maintain optimum contactpressure.

• Switcb interphase and end barriers(where required for BIL ratings) areeasily removed to facilitate cabletermination.

o Door holders store above door open­ings, in fuU view with doors open,behind doors when closed.

4) Aluminum hinges and stalnless­steel pins.

o Cln::uit diagram provides instantview of circuit configuration. Labelalso gives complete switch and fuseratings.

• Ground pads (inside enclosure)accommodate connectors for attach­ment of ground leads and optionalground studs.

CD Mini·Rupter Switch_

• Tenninals can accommodate a vari­ety of cable-terminating devices forcable sizes through 1000 kc mil onswitch terminals, 4/0 maximum ontwo-position fuse terminals.

• S&C Power Fuses with UnI·Rupter­SML Power Fuses or Fault FiterElectronic Power Fuses (shown).

e Grappler-the S&C fuse handlingfitting provides effortless balance, asure grip, and positive control ... ittakes the work out of fuse handlingso that opening, closing, installing,and replacing fuses is easy.

o Storage racks accommodate up to sixSM-4e Refill UnH.s or three SMU·20eFuse UniLs per rack ... you can easilyrestore service without delay.

Figure 7. Hlgh-Yoltage compartments In source-trans'erpad·mounted gear with switch compartment at right, fus.compartmentat left.

663A.30 DESCRIPTIVE BULLETINPage 12 of 20September 23, 1991

sac ELECTRIC COMPANY. Chicago IiIIIsac ELECTRIC CANADA LTD•• Toronto III!J

ICOMPONENTS - Continued

.. S&C's lntnldur'· Finishing Systemprotects the steel with a thoroughcleaning, phosphatizing and ~aling,

dense epOxy powder coating, and highsolids acrylic topcoating for ultravi­olet protection. This tough, uniform,multistage, baked-on finish providesexceptional performance proved by avigorous battery of industry tests.

e Wide bll1khead-type doors provideeasy access to low-voltage controlcompartmenL

4D Doorrtanges-deep double-thickness9O-degree nanges on the extra-ruggedcontrol-eompartment doors overlapwith 9O-degree flanges around dooropenings, adding rigidity and assuringcompression ofgasketing.

f1!) Vents promote ventilation andprevent condensation. Barnes andfilters inside the vents thwart probing,foil tampering, and keep outcontaminants.

• Lastingly resilient compression gas­keting completely seals each control­compartment door opening ... keepswater OUL

fa Instruction manual bolder.

f!) Encl08ure bue is formed (romcontinuous deep OO-degree nanges.Resilient closed-cell gasket protectsthe finish on the nange from beingscratched during installation andisolates it from the alkalinity o( aconcrete foundation.

I

• Penta·Latch8 Me(:banlsm providesvandal·resistant three-point doorlatching for S&C Pad-Mounted Gear.The Penta-Latch Mechanism latchesautomatically when the door is closedand can be unlatched only with apentahead socket wrench or tool. Thelatching mechanism is fully coordi­nated with the provisions (or padlock­ing-a padlock can be installed onlyafter the door is closed and com­pletely latched, and the mechanismcan be unlatched only after thepadlock has been removed. Astainless-steel protective hood shieldsthe padlock shackle to discouragetampering.

Figure 8. Low-yoltage control compartment In source-transfer pad-mounted gear Is conveniently located, giyes full accessto controll without expolure 10 high Yoltage.

SIC ELECTRIC COMPANY. Chk:agoSIC ELECTRIC CANADA LTO.• Toronto

DESCRIPTIVE BULLETIN 663A·30Page 13 of 20

September 23, 1991

sac Source-Transfer PMH Pad-Mounted Gear IOutdoor Distribution (14.4 kv and 25 kv)

ICOMPONENTS - Continued

With Micro-ArlO Control

Isac's Micro-AT Source-Transfer Control has all the features you need forreliable, programmed automatic transfer on your primary-selectivesystem •.• plus options to bring you the ultimate In control circuitry.

The Micro-ATSource-Transfer Control is utilized in S&CSource-Transfer Pad-Mounted Gear in conjunction withMini·Rupler Switches driven by stored-energy opera­tors, to provide for automatic source transfer ofcommon-bus primary-selecUve systems. This controlcontinuously monitors the condition of both powersources and inil.iates automatic switching whenpreferred-source voltage has been lost (or reduced toa predetermined level) for a period of time sufficientto conflTm that the loss is not traJ1sient. The switchassociated with the preferred source is automaticallyopened and the alternate-source switch is thenautomatically closed, restoring power to all loads.

The MicnrAT control uses an advanced electronicmicroprocessor to perform specific control operations,as directed by settings programmed into the device atthe factory and in the field. These setLings, which consistof the source-transfer control's operating characteris­tics and voltage-, current-, and time-related operatingparameters, are entered into the conteol by means ofa keypad on the front panel of the control.

To simplify entry and review of the settings on thcliquid-crystal display (LCD), the operating character­istics have been grouped together as a series of itemsin the ~CONFIGURE"mcnu. Similarly, the voltage-, cur­rent-, and time-related operating parameters have been

grouped together as a series ofilems in the ~VOLTAGE,~"CURRENT," and 1'IME" menus, respectively. Aparticular item can be accessed for display by firstpressing the appropriate menu key and then scrollingthrough the items, using the ~T" or "LAST' itemkey. To prevent unauthorized changes to the operatingcharacteristics and operating parameters, each itemis protected by an access code; the correct access codemust be entered before the item can be altered.

Field adjustable operating characteristics includeselection of preferred source, automatic or hold returnmode, and open-transition (nonparaUeling) or c1osed­transition (paralleling) auLOmatic retransfer. Ifdesired,the source-transfer control can be permanently set atthe factory for hold return and/or open-transitionautomatic retransfer. Operating parameters that arefield adjustable include Ioss-of-source and return-of­source voltage levels, in addition to the voltage levelfor the optional unbalance detection feature. Thecurrent level for the optional overcurrent-Iockoutfeature is al...o field adjustable as are the time delaysfor loss-of-source and return--of-source voltages and forlockout reseL, which is furnished with optionalovercurrent lockout. Additional optional featuresinclude provisions for remote indication and supervi­sory control.

Proven solid-state electronic circuitry and outstanding designfeatures assure the superior performance of the sac Micro-ATSource-Transfer Control.

S&C solid-state electronic devices offer the superiorreliability and serviceability required for the rigors ofoperation in power equipment. MeLal-oxide surgeprotectors at critical points in the control circuitsprovide the optimum in surge protection-S&C's uniquesurge control has been field proven through years ofsuccessful application in hostile utility-substationenvironments. And the capability of every S&C elec­tronic device to withstand voltage surges is confIrmedby two factory quality-check tests: The ANSI SurgeWithstand Capability Test (ANSI Standard C37.9l.1);plus a much more severe (5-kv, 3.75-joule) capacitive­discharge test specially developed by S&C to duplicateor exceed voltage surges measured in EHV powersubstations. The specified surges are applied at aUterminals of the device. AddiLionai tests are performedto identify and eliminate any components that might

be prone to early failure. They include a dielectric tcst;72-hour screening test consisting of 24 hours atmaximum-design operating temperatures followed by48 hours of temperature cycling; and functional tests(both before and after the screening test).

Printed-circuit-board construction assures highreliability. All components are applied at well belowMIL-STD design guidelines, minimizing componentstress, power-supply requirements, and internalheating. Voltage-level settings are maintained within±3% accuracy over an ambient temperature r.rnge of-4<rF to +l6<rF.lntereonnecting-cable connector pinsand receptacle contacts are gold-over-nickel plated.And all output relay contacts are of silver-cadmiumoxide to ensure long service life. Output circuits arerelay isolated.

663A.30 DESCRIPTIVE BULLETINPage 14 of 20September 23, 1991

SIC ELECTRIC COMPANY. Chicago lIBS&C ELECTRIC CANADA LTO•• Toronto IIIIt

I.;;C;.;O;.;M;.;P~O;;.;.;N.;;E;.;N.;.T.;;S_.;;C;.;o;;;n.;;ti;.;nu;;.;e;;d:.... 1

Left source voltage IndIcat­Ing lamp. If serving load.lamp lights when inputvoltage exceeds the prede­termined loss-ol-sourcevoltage setting (factory-setat 85 volts on a 120-voltbasis), indicating that"acceptable" voltage ispresent

Right source voltage Indi­cating lamp. If not servingload, lamp lights wheninput voltage exceeds thepredetermined return-of­source voltage setting(factory-set at 105 volts ona 120-volt basis), indicatingthat "acceptable" voltage ispresent

Test menu key for check­ing functioning of the con­trol's lamps, display, andkeypad. Also used to en­able test keys for simulat­ing an overcurrent or lossof voltage on the sources

•• - -I'---Examlne menu key allowsreview of present sourcevoltage and current inputs,and the present status(active or inactive) of dis­crete inputs to and outputsfrom the source-transfercontrol

Two-line 48--character LCDwith backlighting

"'II~~-~~~-lr-- Manual/automatlc opera­, tlon selector switch-when

in manual position. pre­vents an automatic sourcetransler; permits manualoperation using the openlclose puShbuttons

--\fOWl

MM'M

2 3 +

4 5 6 ..7 8 9 - MO·-,

'M 'M• ~ 0 lOll" •.,. M'•

""lOll _

. ~

Automatic-transfer "ready"Indicallng lamp providesstraightforward Indicationthat source-transfer con­trol, interrupter switches,and switch operators are inthe correct positions andmodes for automaticsource transfer

Overcurrent-Iockout Indi­cating lamp and reset key.(Furnished with optionalovercurrent-Iockout fea­ture.) Blue lamp lightswhen an overcurrenl inexcess of the predeter­mined setting (factory-setal 480 amperes) occurs,and automatic sourcetransfer is prevented untilthe control is reset. Withoperation selector switchIn manual position, resetkey can be pressed to can­cel the lockout conditionand extinguish the bluelight

Test keys to simulate over­current and ross of voltageon the right source

Event menu key allowsdisplay of system status,control status, and operat­ing conditions for pastcontrol operations. Eachoperation is indicated byillumination of the lamp onthe key. The last 130eventsare stored in memory atany given time

Unbalance detection (fur­nished with optional unbal­ance detection feature).Initiates automatic sourcetransfer if an unbalancecondition exceeds a presetreference level (factory-setat 30 volts. field program­mable in the voltage menu)

Test keys to simulate over­current and loss of voltageon the lett source

Lasl and nexlltem keys Keypad

Figure 9. Closeup 0' 'ronl panel of Micro-AT Source-Trans'er Conlrol.

DESCRIPTIVE BULLETIN 663A·30S&C ELECTRIC COMPANY. ChicagoS&C ELECTRIC CANADA LTD•• Toronto

Page 15 of 20September 23,1991

S&C Source-Transfer PMH Pad-Mounted Gear IOutdoor Distribution (14.4 kv and 25 kv)

With Micro-Ar- Control

I~C;.;O;.;M~p;;;O,;,N;;;E;;,N;,;T.;s~.;c;.;o;.;.n;;;li;.;n;;;ue;;;d;.. 1

All controls for stored-energy operators and source·transfer control arereadily accessible, easily identified, and conveniently located within agrounded, steel-enclosed low-voltage compartment ••• it's isolated frommedium voltage and shielded from the elements.

High-speed stored-energy switch operators provideautomatic trlp-open and trip-closed operation oltheS&C Mini-Rupters in respoll.8e to signals from theMiero-AT Source-Transfer Control. Their quick-makeqllick·break mechanisms are automatically rechargedafter each trip operation when voltage is present onthe associated source.S&C's stored-energy operators are employed in S&CSource-Transfer Pad-Mounted Gear to provide high­speed power operation of two Mini·Hupter Switches.In conjunction with the interrupter switches, thestored-energy operators provide high-speed automaticsource transfer and circuit interruption for criticalloads. These operators incorporate a quick-make quick­break, stored-energy mechanism which opens andcloses the Mini~Rupter swiftly and positively. Sourcetransfer is accomplished in 10 cycles plus anytime delayfor coordination. The quick-make quick~break mech~

anism is solenoid tripped in response to a control signal,or manuaUy tripped using open/close pushbuttons orthe emergency-trip provisions.

The stored-energy operators provide both automatictrip-open and automatic trip-dosed !>-wit.eh operation.Motor charging of the operator's quick-make quick­break mechanism is automatic after each opening orclosing operation when voltage is present on theassociated source. The stored~energy operators areintegrally mounted within the grounded, steel-enclosedlow-voltage compartment which is located in one sideof the pad-mounted gear-isolated from mediumvoltage.

All internal parts of the stored-energy operators aregalvanized, zinc-nickel plated, or of nonferrousmaterials to protect against corrosion. Gold-surfacedauxiliary switch contacts are provided on the stored­energy operators for external control circuits servingsolid-state devices. •

Decoupling mechanisms are provided to permitconvenient decoupling of the switches from the switchoperators for functional testing of source~transfer

schemes and elective exercising ofstored~energyswitchoperators, without disturbing medium-voltage powercircuits. DecoupUng is readily accomplished by releasingthe coupled-position latch and moving the decouplerhandle upward to the decoupled position. When theoperator is decoupled, its associated Mini-RupterSwitch is locked open or closed, depending upon switchposition at the time of decoupling. The decouplerindicator located on the decoupler handle showswhether the operator is coupled to the interrupterswitch or decoupled. While an operator is decoupled,the ·ready" lamp on the Micro-AT control will not light­serving as another reminder oCthe decoupled condition.

A number ofoptional features are offered that furtherenhance operating flexibility. The optional anti­paralleling device is available to preclude parallelingof the incoming sources. This device prevents themanual or automatic closing of one interrupter switchwhen the other interrupter switch is closed_ Auxiliaryswitches, to foUow the position of the interrupter switchand/or the stored-energy operator, are also offered asoptions.

Other available options include key interlocks toguard against opening fuse-compartment doors unlessboth interrupter switches are locked open, andmechanical cable interlocks to prevent operation of asource interrupter switch when the associated switch­compartment door is open. These interlocks arerequired for users who must comply with the NationalElectrical Code.

663A.30 DESCRIPTIVE BULLETINPage 16 of 20September 23, 1991

S&C ELECTRIC COMPANY. Chicago ~S&C ELECTRIC CANADA l TO•• Toronto gJt

I.;;C:.:O:.;M;;P;.O::.:.:N.:;E:.:N~T.::S_.;;c:.:o::;n.::ti;;nu::;e:.:d:.... 1

Remote-control receptacle (optional) for attachment ofoptional remote-control sial ion 10 permit open-closeoperalions Irom an adjacent area-manual/automaticoperation selector switch on Micro-AT Source-TransferControl must be in manual position

Open/close pushbuttons permit localelectrical operation when manual/auto·malic operation selector switch is inmanual position

Three-posillon operation leleclor: Operating positionpermits manual or electrical opening and closing of switchor, when switch is decQupled. exercising and testing ofstored-energy operator without opening or closing inter­rupter switch; lock position prevents all electrical andmechanical operation when padlocked; charging positionpermits manual charging 01 operator mechanism whileprOhibiting electrical and mechanical tripping

Operation counter registers number of operations of stored­energy operator

Figure ". Decoupler handle moves upwardto decouple ... downward to couple.

Charging shalt for insertion of notched end01 dual-purpose manual handle for chargingquick-make quick-break mechanism in theevent control power ;s not available

Swltch·posllion target indicates whetherMini-Rupter Switch is open or closed

Decoupler handle permits convenient decou­piing of switch from switch operator forfunctional testing of source-transfer schemesand exercising of switch operators withoutdisturbing medium-voltage power circuits

Emergency trtp: Keyed end of dual-purpose manual handlecan be inserted into port to initiate local manual open-doseoperation when control power is not available lor localelectrical operation

Operator targets show whether quick·makequick-break mechanism is charged or dis­charged, and whether operator is in switch­open or switch-closed position

Decoupler Indicator shows whether switchoperator is coupled to the Mini-Rupter Switchor decouple<!

Dual-purpose manual tlandle-upper notched end of dual­purpose handle is used lor Charging and lower keye<! endof handle is used for tripping the quick-make quick-breakmechanism when control power is not available

Figure '0. low-voltage control compar1ment showing features of the high­speed stored·energy switch operators.

DESCRIPTIVE BULLETIN

SIC ELECTRIC COMPANY. ChicagoSIC ELECTRIC CANADA l TO.• Toronto

663A·30Page 17 of 20

September 23, 1991

sac Source-Transfer PMH Pad-Mounted Gear IOutdoor Distribution (14.4 kv and 25 kv)

With Micro-ArlO Control

l"'c;.;o;.;M;,;,p;,.o=N,;;E;,.N"'T,;;s_"'c;.;o;;.n;;.ti;,;,n;;.ue;.;d;.... ......1sac's field proven Mini-Rupter Switches are poweroperated ••• handle all your three-pole switchingrequirements up through 600 amperes at 14.4 kv,400 amperes at 25 kv, with two-time duty-cyclefault-closing ratings of 22,400 amperes rmsasymmetrical at 14.4 kv, 20,000 amperes rmsasymmetrical at 25 kv.

Multl'lnger, convex, sliver-plated copper con­tacts provide equalized, four-point pressure onthe blade's silver-clad contact sur/aces

Cypoxy Insulalor. provide generous leakagedistance and are self-scouring and nontracking

Arc comprenor provides controlled circuit interrup­tion without external arc or Ilame, and without the needfor separate auxiliary blades. A unique lip-seal wipesblade as blade exits arc compressor-keeps afC undercompression, directs arc gases through deionizingsuppressor vent

Multipurpose, one-piece, formed hard·drawn copper bladefeatures silver-clad contact surfaces on both sides-it'sutilized for circuit closing, continuous current carrying. andcircuit interrupting. The blade's simple, reliable, high-speedaction is unlike the uncertain action of au~i1iary interrupting­blade-and-contact mechanisms which are dependent uponretention of correct sequencing with the main blade andcontact. and upon spring assistance to snap the interruptingblade open

Cypoxy operatlng .haft positions blades in "fixtured"alignment. S&C's Cypoxy resin system is employed --­as the assembly medium to produce a unified insulatedshaft with blade supports and journals permanenllymolded in place

Shain-guard terminals. Terminal pads and support bracketson voltage sensors are uniquely designed to protect Mini­Rupter against damage from excessive cable or foundationmovement. This design permits terminal pad to deflect whensuch movement occurs but prevents transmission ot forcesto the stationary blade-support contact assures idealcontact position and pressure

S&C Voltage Sensor.-each consisting of a high-voltage capacitorand series transformer-produce an output voltage directlyproportional to line-to-ground vollage, with relay accuracy over anambient temperature range of -40· F 10 +160· F; provide three-phasesensing and control powerforthe automatic source-transfer scheme;supply power to charge and trip the stored-energy operators; andreplace apparatus support insulators. Their construction assureshigh cantilever strength, and Bil and dielectric characteristicsequivalent to that of the apparatus insulators replaced. Thesesensorsrequire no primary fusing, Secondary conductors of the voltagesensors are shielded from medium voltage by switch-frame channels

Figure 12. Mini-Rupter Switches are positioned back-to-backand mounted In tandem with the low-voltage compartment,permitting direct-drive power operation by stored-energyoperators. One 01 the 14.4-kv, 600-amp Mini-Rupters Is shownwIth barriers removed for clarity.

663A.30 DESCRIPTIVE BULLETINPage 18 of 20September 23, 1991

S&C ELECTRIC COMPANY' Chicago II'JIS&C ELECTRIC CANADA LTO•• Toronto IIUt

I.,;C;;.;O;;.;M.:;:.P;;;O.:.;N:.;E.:.;N;.;T.;;S;.....;c;;.;o;;,n;;;ti.:.;n;;,ue;;;d;... ---11You have a choice of three S&C Power Fuses with Uni·Rupter ••• TypeSML·20 or SML·4Z Power Fuses, or Fault Fiter Electronic PowerFuses ••• all have blown·fuse indication.

Faull FIt« Eleetronic Po- FIlM (ptc­tured above) is rated ..00 amp maxcontinuous and 22,400 amp rms asym­metrical (''',000 amp rms symmetficl,l)interrupting at 1..... ltV; 200 Imp m&ll.continuous and 20,000 amp rms asym­melrical (12,500 amp rm. symmetrical)interrupting at 25 kv. Fuse uses replace­able interrupting module and reusablecontrol module

Biown-Iule Ilrgll i. brllllani blaze­orange color ... appears at tOP 01 inter­rupting module alter electronic powerfuse operates. and factory-presettarget is lucent by daylight or flashlight

Blown-luN "rgal is lIuorascant fire-redcolor ... moves to "BLOWN" indicatorwindow in translucent holder when luseoperates. and Iluoresces at night whenilluminate<! with a flashlight, permittingpositiVi! visual check 01 luse conditionwilhout removing luse hom mount­ing ... and target is reset by simplyreplacing the expendable rerill unit

SML...-Z Po_r FUM (pictured above) usesSIC's SM"- Relill Unit and is rated 200E ampmax continuous: 20,000 amp rms asymmet­rical (12.500 amp rms symmelrical) inter­rupting at both 1..... kv and 25 ltv

L. byrln Ih Ine ,nencer-8breakthrough in power­fuse exhaust control Ihatvirtually eliminates venling.fuse operation is silent

sac', Unl-Rupt.,t per-

__------..!''''..'C'~ __-----;7mits single-pole liveswitching of fuses ... afirm, vigorous openingpull on Ihe fuse with ahookslick is all that'srequired to aChieve cir­cuit Interruption. Uni­Rupler self-resels 'orthe nexl opening oper­ation and has separatecurrent-carrying andfaull-closing contacts

..•

, ,

SML·20 Power FUM (pictured above) fea­tu'" S&C's SMU-20 Fuse Unit, designed loruniversal use on both your undergroond andoverhead distribution syslems. SML-20Power Fuses are rated 200E or 200K ampmax continuous; 22,'00 amp rms asymmet­rical (1".000 amp rms symmetrical) inter­rupting at 1..... ltv: 20.000 amp rms asym­metrical (12,500 amp rms symmetrical)interrupting at 25 ltv

~ B'ow.-'o" '''0'' I' '0"'"0'-'"color ... projects Irom top 01 SML-20Power Fuse upper end lilting whenluse unit has operate<! ... automat­ically resets within end lilting whenblown ruse unit is replaced ... andluse condillon is easily Checked withluse in closed position

t S&C Power t"uses WIth Uni-Rupter have a one-time duty-cyc1e fault-dosing capabiJity equal to the interrupting rating of the fuse, ..·ith• tv..o-time capability of 13.000 amperft' fillS asymmetrical These values denne the a\'8iIaI»e fault current into which the fuse can be cloeedthe specified number of times (once or twice), when operat.ed vigorously through its full tra\'el without hesit.ation, with the Uni·Rupt~ remainingoperable and able to carry and interrupt rated current.

Figure 13. Protection of your distribution syslem may be achieved using one of theae three fuses. Each fuse Is equippedwith Uni-Rupter, for single-pole live switching 01 single-phase or three-phase load circuits.

sac ELECTRIC COMPANY. Chicagosac ELECTRIC CANADA LTD.• Toronto

DESCRIPTIVE BULLETIN 663A·30Page 19 of 20

September 23, 1991

sac Source-Transfer PMH Pad-Mounted Gear IOutdoor Distribution (14.4 kv and 25 kv)

With Micro-AT'- Control

I..;;,O;..PT;.;;IO;.;.N.;.;;S IChoose from a wide variety of optional features-in addition to those alreadydescribed-that will further enhance the level of flexibility and operatingconvenience you can achieve on your power distribution system ••• hereare just a few of the available choices.

Ground studs-available on switch and fuseterminals, as well as on the ground pad ineach compartment-matched to the short­circuit rating of the gear, are convenientlylocated for easy access

Surge Arresters are available in9-kv through 18·kv ratings forapplication at source-side switchterminals. Arreslers are groundedthrough a low-impedance bus

Current sen.ors, Included with option­al overcurrent-lockout feature, mounton each source conductor-just belowcable terminator-to provide sensingfor conditions that indicate a sourcetransfer should not be performed

Switch-terminal adepters may be added toaccommodate two conductors per phase.Inset shows one switch terminal with anadapter in place

Dual-purpose front barriers for fuses and switches. Fusebarriers in their normal position (left-hand phase) guardagainst inadvertent contact with live parts. They can be liftedout and inserted into the open gaps when fuses are in thedisconnect position (center phase). For switches, a single­piece three-phase barrier (not shown) is furnished plus awindow panel to permit visual check of switch positionwithout removing barrier

Cable guide. (require use ofa cable pit or base spacer)assist in cable training

Base .pacer. are available, either steel­compartmented to match the pad-mountedgear enclosure or noncompartmented, toprovide increased elevation of ungroundedparts above mounting pad

Figure 14. S&C Source-Transfer Pad-Mounted Gear showing a tew ot the available optional features. An optional stainless­steel enclosure Is also available for users requlrlng the ultimate in corrosion resistance.

663A.30 DESCRIPTIVE BULLETINPage 20 of 20September 23,1991

S&C ELECTRIC COMPANY. Chicago BJIS&C ELECTRIC CANADA LTD.• Toronto III!I