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SHUNT TRIP FOR SERVICE DISCONNECT

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ronmarx

Electrical
May 27, 2003
4
NEED AN OUTDOOR SERVICE DISCONNECT FOR 1600A, 480V SERVICE WITH (6)-4" UNDERGROUND CONDUITS (25FT TOTAL LENGTH)FEEDING A MOTOR CONTROL CENTER JUST INSIDE BLDG FROM A 13.2KV/480V XFMR JUST OUTSIDE THE BLDG. SHORT OF A 1600A, 480V BREAKER OUTSIDE WOULD A SHUNT TRIP COIL ON THE MCC MAIN BREAKER AND A PUSHBUTTON MOUNTED TO THE BLDG EXTERIOR WALL BE AN ACCEPTABLE SERVICE DISCONNECT ?
 
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Not to me it wouldn't. The pushbutton is not a service disconnecting means per NEC definition. It can't be locked open to prevent someone from closing the breaker back in. And the shunt trip requires a source of control power to function.

Who's telling you the disconnect has to be outside?

(Ron - find the Caps Lock key on your computer and give it a little punch :cool:)
 
The outdoor service disconnet will be your code required service disconnect. The shunt-trip you mention is not prohibited for emergency stop but it will not be considered a servcie disconnect. You don't have to have the service disconnet inside the building. Where is your metering?

Why do you need the push-button? Emergenc power off? If you want to work on the MCC safely, only acceptable method is to lock out the outdoor switch.
 
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