Applications

Common uses of Kirk Key interlocking systems in electrical infrastructure

Kirk keys ensure that the supply switch is open before the padmount transformer cabinet can be accessed for maintenance or repairs.

Prevents access to energized equipmentCommon in underground distributionProtects maintenance workers

Interlocks on load break switches prevent operation under unsafe conditions and ensure proper sequencing in switchgear lineups.

Sequence control for multiple switchesPrevents parallel operationUsed in substations and switchyards

In loop feed distribution systems, Kirk keys control the sequence of switch operations to maintain proper load flow and prevent backfeeds.

Controls sectionalizing operationsPrevents backfeed conditionsEnables safe fault isolation

Kirk keys prevent circuit breakers from being racked in or out while in the closed position, protecting against arc flash incidents.

Rack-in/rack-out controlArc flash protectionBreaker position verification

In power generation facilities, Kirk keys ensure generators cannot be connected to the grid until proper synchronization conditions are met.

Sync check interlockingProtects against out-of-phase parallelingCritical for generator protection

Kirk keys ensure that equipment is de-energized and isolated before grounding switches can be closed for maintenance work.

Verifies isolation before groundingLOTO supportEssential for safe maintenance

Industry Standards

Kirk Key interlocking systems are designed and installed in accordance with various industry standards and regulations:

NFPA 70E

Electrical Safety in the Workplace

IEEE C37

Switchgear Standards

OSHA 1910

Electrical Safety Standards

IEC 62271

High-Voltage Switchgear

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