Transfer switches

[steve5352]

I have a customer with a co-gen plant who wishes to connect to 4160V utility power to use when the generator is down. I am thinking about a manual transfer switch. Would it be more cost effective to utilize standard breakers with relay interlocking to prevent two sources of power to be energized at the same time?

 

[gordonl]

I would say it would be far cheaper, because even with the transfer switch you would still require these two breakers for protection. (IE - key interlocks between breakers) I've seen cable style interlocks between breakers, but these are less relible, more maintenance, and more easily defeated.

 

[busbar]

If a UL Std 1008 assembly is not required, page 10 of

https://www.ch.cutler-hammer.com/docs/Fred/apscpgh/htmL/550000/K1.PDF

“…interlocked via means of the operating mechanism, and shall also be equipped with a walking beam interlock to prevent simultaneous closing of both sources during manual operation.

http://www.cutler-hammer.eaton.com/unsecure/cms1/6632C94.PDF

http://www.cutler-hammer.eaton.com/unsecure/cms1/6632C46.PDF

http://www.geindustrial.com/products/manuals/GEH-2980D.pdf

"Kirk-key" circuit-breaker interlocks may be another option.