Specification SheetBTPCBypassIsolationTransfer SwitchOpen or ClosedTransition150 – 4000 AmpsDescriptionFeaturesBTPC bypass isolation transfer switchescombine a draw out automatic transfer switchwith isolation mechanism and a manual bypassswitch, to provide redundant power transfer andre-transfer capability for critical need applicationsrequiring a reliable power supply to the load.BTPC switches are available with closedtransition for transferring critical loads withoutinterruption.PowerCommand control: A fully featuredMicroprocessor based control with digitaldisplay. Controls allow operator to enter settingsand make adjustments to software enabledfeatures easily and accurately. Accommodatesup to 8 event schedules.Like conventional transfer switches, BTPCtransfer switches are designed for operation andswitching of electrical loads between primarypower and Standby generator sets. The switchmonitors both power sources, signals generatorset start up, automatically transfers power andreturns the load to the primary power sourcewhen the utility returns and stabilizes.Closed transition available: By brieflyconnecting the two sources (for 100 msec orless), the transfer from the alternate sourceback to the normal source occurs withoutInterruption in the power supply to loads.Programmed transition: Open transition timingcan be adjusted to completely disconnect theload from both sources for a programmed timeperiod, as recommended by NEMA MG-1 fortransfer of inductive loads.Closed door draw out operation: Bypass andtotal isolation of the automatic transfer switchoccurs behind closed doors, to provide arc flashprotection for operator.For critical loads: Suitable for use inemergency, legally required and optionalStandby 2020 Cummins Inc. S-1271 (02/20)

BTPC Bypass-Isolation Transfer SwitchAdvanced transfer switch mechanism:Unique bi-directional linear actuator providessmooth, Continuous transfer switch actionduring automatic operation.Robust control system design: Opticallyisolated logic inputs and isolation transformersfor AC power inputs provide high-voltage surgeprotection.Main contacts: Heavy-duty silver alloy contactsand multi-leaf arc chutes are rated for motorloads or total system load transfer. They requireno routine contact maintenance. Continuousload current not to exceed 100% of switch ratingand Tungsten loads not to exceed 30% of switchrating. The automatic switch and bypass switchhave the same ratings.Communications capability: The transferswitch is capable of communicating with othertransfer switches, SCADA networkedaccessories, or Cummins generators utilizingLonWorks protocol.Easy service/access: Single-plug harnessconnection and compatible terminal markingssimplify servicing. Access space is ample. Doormounted controls are field-programmable; notool is required.Complete product line: Cummins offers a widerange of equipment, accessories and services tosuit virtually any backup power application.Warranty and service: Products are backed bya comprehensive warranty and a worldwidenetwork of distributors with factory-trainedservice 2020 Cummins Inc. S-1271 (02/20)

Transfer Switch MechanismBypass Mechanism Transfer switch mechanism is electrically operated andmechanically held in the Source 1 and Source 2positions. The transfer switch incorporates electrical andmechanical interlocks to prevent inadvertentinterconnection of the sources. Independent break-before-make action is used for both 3pole and 4-pole/ switched neutral switches. This designallows use of sync check operation when required, orcontrol of the operating speed of the transfer switch forproper transfer of motor and rectifier-based loads(programmed transition feature). True 4-pole switching allows for proper ground (earth)fault sensing and consistent, reliable operation for the lifeof the transfer switch. The neutral poles of the transferswitch have the same ratings as the phase poles and areoperated by a common crossbar mechanism, eliminatingthe possibility of incorrect neutral operation at any point inthe operating cycle, or due to failure of a neutral operator. High pressure silver alloy contacts resist burning andpitting. Separate arcing surfaces further protect the maincontacts. Contact wear is reduced by multiple leaf arcchutes that cool and quench the arcs. Barriers separatethe phases to prevent interphase flashover. A transparentprotective cover allows visual inspection while inhibitinginadvertent contact with energized components. Switch mechanism, including contact assemblies, is thirdparty certified to verify suitability for applications requiringhigh endurance switching capability for the life of thetransfer switch. Withstand and closing ratings arevalidated using the same set of contacts, furtherdemonstrating the robust nature of the design. Manual bypass switch mechanism allows the operator toselect either the normal or emergency source by closingthe bypass contacts. Visual indicators show bypass“source selected”, bypass "closed" or "open" to eithersource, and automatic transfer switch isolation or"disable." Bypass of the automatic switch isaccomplished with permanently mounted, mechanicallyoperated devices without disturbing the power supply tosystem loads, and without opening enclosure door. Isolation contacts allow the automatic transfer switch andthe bypass switch to be separated electrically andmechanically. The automatic transfer switch is isolated bya draw out mechanism similar to that used on powercircuit breakers on transfer switches rated 1200 ampsand less. On 1600-4000 amp models the draw outcarriage is wheel-mounted. Protective safety shutters, provided on switches up toand including 1200 amps, cover the stationary powerterminals on the bypass switch when the automatictransfer switch is isolated and removed. The draw out mechanism can be latched in one of threepositions: “connected”, “test”, and “isolated”. In theconnected position the mechanism is locked. In the testposition, the automatic switch is isolated but the controlsreceive power. In the isolated position, the automaticswitch is completely isolated. The bypass switch mechanism is identical to theautomatic switch except it is mechanically operatedrather than electrically operated. Mechanical interlocksprevent operation of the bypass or automatic switches inany mode that would result in the interconnection of 2020 Cummins Inc. S-1271 (02/20)

PowerCommand ControlPowerCommand controls are microprocessor based anddeveloped specifically for automatic transfer switchoperation. The control includes the features and optionsrequired for most applications. Flash memory stores the control settings. Contents of the memory are not lost even if power to thecontroller is lost. On-board battery maintains the real-time clock settingand the engine start time delay.PanelsBasic indicator panel:Source available/connected LED indicatorsTest/exercise/bypass buttonsDigital display: StandardAnalog bar graph meter display: optional (D009)Control Functions: Level 2 ControlOpen transition (in-phase)Open transition (programmed)Closed transition: Includes fail-to-disconnect timer toprevent extended paralleling with the utilityUtility-to-genset applicationsUtility-to-utility applicationsGenset-to-genset applicationsSoftware adjustable time delays: Engine start: 0 to 120 sec Transfer normal to emergency: 0 to 120 sec Re-transfer emergency to normal: 0 to 30 min Engine stop: 0 to 30 min Programmed transition: 0 to 60 secUndervoltage sensing: 3-phase normal, 3-phaseemergency Accuracy: 2% Pickup: 85% to 98% of nominal voltage Dropout: 75% to 98% of pickup setting Dropout time delay: 0.1 to 1.0 secOvervoltage sensing: 3-phase normal, 3-phaseemergency Accuracy: 2% Pickup: 95% to 99% of dropout setting Dropout: 105% to 135% of nominal voltage Dropout time delay: 0.5 to 120 secOver/under frequency sensing: Normal and emergency Accuracy: 0.05Hz Pickup: 5% to 20% of nominal frequency Dropout: 1% beyond pickup Dropout time delay: 0.1 to 15.0 secVoltage imbalance sensing: Dropout: 2% to 10% Pickup: 90% of dropout Time delay: 2.0 to 20.0 secPhase rotation sensing: Time delay: 100 msec Loss of single phase detection Time delay: 100 msecLoss of single phase detection Time delay: 100 msecProgrammable genset exerciser: Eight events/scheduleswith or without 2020 Cummins Inc. S-1271 (02/20)

PowerCommand Control (continued)Time-Delay FunctionsUser Interface OptionsEngine start: Prevents nuisance genset starts due tomomentary power variation or loss. Not included in utilityto-utility systems.Transfer normal to emergency: Allows genset to stabilizebefore application of load. Prevents power interruption ifnormal source variation or loss is momentary. Allowsstaggered transfer of loads in multiple transfer switchsystems. For genset-to-genset applications, delays transferof load from lead to secondary generator.Re-transfer emergency to normal: Allows the utility tostabilize before re-transfer of load. Prevents needlesspower interruption if return of normal source is momentary.Allows staggered transfer of loads in multiple transferswitch systems. For genset-to-genset applications, delaysre-transfer of load from secondary back to lead generator.Engine stop: Maintains availability of the genset forimmediate reconnection if the normal source fails shortlyafter transfer. Allows gradual genset cool-down by runningunloaded. Not included in utility-to-utility applications.Elevator pre-transfer signal: Requires optional relaysignal module (M023). Delays transfer for pre-set intervalof 0-60 seconds to prevent a power interruption duringelevator operation.Bar graph meter display (D009): An LED bar graphdisplay provides an easy-to-read indicator of the level ofpower being supplied to the load. Information displayedincludes: 3-phase voltage and current, power factor, andkilowatts. Green, amber and red LEDs provide at-a-glanceindication of system acceptability.Front panel security key (M017): Locks front panel toprevent access to digital control settings. Preventsunauthorized activation of transfer or test functions.User InterfacesBasic interface panel: LED indicators provide at-a glancesource and transfer switch status for quick summary ofsystem conditions. Test and override buttons allow delaysto be bypassed for rapid system checkout.Digital display: The digital display provides a convenientmethod for monitoring load power conditions, adjustingtransfer switch parameters, monitoring PowerCommandnetwork status or reviewing transfer switch events.Password protection limits access to adjustments toauthorized personnel. The digital display (M018) isstandard on the BTPC.Control OptionsRelay signal module (M023): Provides relay outputcontacts for sending information to the building monitoringand control system. Relay outputs include: Source 1connected/available, Source 2 connected/available, not inauto, test/exercise active, failed to disconnect, failed tosynchronize, failed to transfer/re-transfer, and elevatorcontrol pre-transfer signal.Loadshed (M007): Removes the load from the emergencypower source by driving the transfer switch to the neutralposition when signalled remotely. Transfers load back tothe emergency source when the signal contacts open.Immediately re-transfers back to the primary source whenavailable. For utility to- generator applications only.PowerCommand network interface (M031): Providesconnection to the PowerCommand network. LonWorkscompatible for integration with building monitoring andcontrol system.Load power and load current monitoring (M022):Measures load phase and neutral, current, power factor,real power (kW) and apparent power (kVA). Warns ofexcessive neutral current resulting from unbalanced ornonlinear loads. Minimum current level detection is 2020 Cummins Inc. S-1271 (02/20)

SpecificationsVoltage rating600 VAC, 50 or 60 HzArc interruptionMultiple leaf arc chutes provide dependable arc interruption.Neutral barA full current-rated neutral bar with lugs is standard on enclosed 3-pole transferswitches.Auxiliary contactsTwo isolated contacts (one for each source) indicating switch position areprovided for customer use. Contacts are normally open, and close to indicateconnection to the source. Wired to terminal block for easy access. Rated at 10amps Continuous at 250VAC maximum. UL recognized and CSA-certified.Operating temperature-40 F (-40 C) to 140 F (60 C)Storage temperature-40 F (-40 C) to 140 F (60 C)HumidityUp to 95% relative, non-condensingAltitudeUp to 10,000 ft (3,000 m) without de-ratingSurge withstand ratingsVoltage surge performance and testing in compliance with the requirements ofIEEE C62.41 (Category B3) and IEEE C62.45.Total transfer time (source-to-source)Will not exceed 6 cycles at 60 Hz with normal voltage applied to the actuatorand without programmed transition enabled.Manual operation handlesExternal manual operator is provided via the bypass and isolation mechanism,providing quick make/quick-break operation under load.CertificationsAll switches are UL 1008 Listedwith UL Type Rated cabinets andUL Listed CU-AL terminals.All switches comply with NFPA 70, 99 and110 (Level 1).All switches are certified to CSA282 Emergency Electrical PowerSupply for Buildings, up to 600VAC.All switches comply with NEMA ICS 10.Suitable for use in emergency,legally required and Standbyapplications per NEC 700, 701and 702.All switches comply with IEEE 446Recommended Practice for Emergencyand Standby Power Systems.This transfer switch is designedand manufactured in facilitiescertified to 2020 Cummins Inc. S-1271 (02/20)

Transition ModesOpen transition/programmed: Controls the timerequired for the device to switch from source to source, sothat the load-generated voltages decay to a saf