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#79577 - 01/06/02 07:49 AM Service and ATS
tmon Offline

Registered: 07/05/01
Posts: 29
Is it legal to run a service from the utility transformer to an automatic transfer switch prior to the overcurrent device (service disconnect means)? The load is an MCC protected with a built-in main circuit breaker for a sewer lift station. The ATS is 2 1/2 feet from the MCC. Thanks

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#79578 - 01/06/02 08:25 AM Re: Service and ATS
Elzappr Offline

Registered: 12/20/01
Posts: 273
Loc: Oregon
What we did on a similar job (for a situation where it wasn't feasible to re-route, or tap on to, the service entrance conductors) was to add a "top hat" to the service equipment, and route the load side of the main disconnect section up and over to the transfer switch/ground fault sensor, and then back to the rest of the load. This required buying custom made bus bars from the switchgear manufacturer in order to feed the transfer switch and the load side of the gear. Make sure that bracing for the bus bar modification is designed ahead of time, you don't want those new bus bar extensions pointing up to the top hat to be flappin' in the breeze!

[This message has been edited by Elzappr (edited 01-06-2002).]

[This message has been edited by Elzappr (edited 01-06-2002).]

#79579 - 01/06/02 10:38 AM Re: Service and ATS
Nick Offline

Registered: 08/13/01
Posts: 603
Loc: Riverside, CA
As I learned in another thread, on another forum, when installing a transfer switch ahead of the service disconnect the TS becomes the service disconnect. It must be listed and marked as suitable for use as service Equipment. Transfer switches marked this way are required, in their listing, to have accessible means to disconnect both sources of supply. Over current protection is allowed to be adjacent to the service disconnecting means. 230-91.
Thanks Don


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