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#51482 - 04/30/05 09:08 AM Homemade Shunt
James Wells Offline
Junior Member
Registered: 04/30/05
Posts: 3
Loc: Mt. Olive,NC,USA
I have been asked to reconnect a music Kill switch on a commercial Dj booth. Two single pole breakers have been tied together with a peg thru the throw handle on the breakers. One breaker controls dj booth power - the other is connected thru a normally open switch that connects to ground. ie: Close the switch breaker trips opening power breaker. This is a "reconnect" ~
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#51483 - 04/30/05 09:36 AM Re: Homemade Shunt
Sir Arcsalot Offline
Member
Registered: 11/17/03
Posts: 127
Loc: Lynden, Washington
I wouldn't want to be around when that switch fails...!
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No wire bias here- I'm standing on neutral ground.
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#51484 - 04/30/05 09:42 AM Re: Homemade Shunt
e57 Offline
Member
Registered: 05/27/03
Posts: 2876
Loc: S.F.,CA USA
So what happens the day the breaker fails?

Sounds like with the existing wiring you could use a real shunt trip breaker.
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Mark Heller
"Well - I oughta....." -Jackie Gleason
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#51485 - 04/30/05 10:10 AM Re: Homemade Shunt
James Wells Offline
Junior Member
Registered: 04/30/05
Posts: 3
Loc: Mt. Olive,NC,USA
I agree A Real Shunt breaker is needed.
Application wise is there anything that requires you not to do it. Breaker finds a ground - trips - Normal Operation ~
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#51486 - 04/30/05 10:15 AM Re: Homemade Shunt
iwire Offline
Moderator
Registered: 01/05/03
Posts: 4391
Loc: North Attleboro, MA USA
Very bad idea in my opinion.

I also believe it would be a violation of 110.7

Quote:
110.7 Insulation Integrity.
Completed wiring installations shall be free from short circuits and from grounds other than as required or permitted in Article 250.


It is very likely along with tripping the branch breaker you will trip a main putting people in the dark.

A handle tie will not always trip the other breaker, it is not intended to do that.

There are so many better ways to cut off a sound system. If I am not mistaken you can actually damage speakers by dropping the power out in the wrong order.

[This message has been edited by iwire (edited 04-30-2005).]
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Bob Badger
Construction & Maintenance Electrician
Massachusetts
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#51487 - 04/30/05 10:24 AM Re: Homemade Shunt
e57 Offline
Member
Registered: 05/27/03
Posts: 2876
Loc: S.F.,CA USA
iwire, good point there! Most sound equipment people I have worked with would have a heart attact if the amp fans were not allowed to run and cool the system before dropping power to it. Definately not good for the equipment either.
_________________________
Mark Heller
"Well - I oughta....." -Jackie Gleason
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#51488 - 04/30/05 10:26 AM Re: Homemade Shunt
James Wells Offline
Junior Member
Registered: 04/30/05
Posts: 3
Loc: Mt. Olive,NC,USA
Thanks Fellows
I appreciate the Info...
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#51489 - 04/30/05 09:23 PM Re: Homemade Shunt
Larry Fine Offline
Member
Registered: 02/18/05
Posts: 693
Loc: Richmond, VA
I haven't thought out all of the ramifications, but how about using a GFCI instead, and using a pushbutton to connect the ground and neutral together.

Almost all GFCI will trip if the neutral is grounded, and there's no bolted-fault current strain on the equipment.
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Larry Fine
Fine Electric Co.
fineelectricco.com
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#51490 - 05/01/05 09:35 AM Re: Homemade Shunt
iwire Offline
Moderator
Registered: 01/05/03
Posts: 4391
Loc: North Attleboro, MA USA
Quote:
how about using a GFCI instead, and using a pushbutton to connect the ground and neutral together.


This would violate 250.24(A)(5)

Quote:
250.24(A)(5) Load-Side Grounding Connections. A grounding connection shall not be made to any grounded circuit conductor on the load side of the service disconnecting means except as otherwise permitted in this article.


How about running a switch leg, or use a contactor etc.

There is no need to short a breaker or trip a GFCI.
_________________________
Bob Badger
Construction & Maintenance Electrician
Massachusetts
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#51491 - 05/01/05 01:45 PM Re: Homemade Shunt
Larry Fine Offline
Member
Registered: 02/18/05
Posts: 693
Loc: Richmond, VA
Oh, sure, bring doing it the right way into the conversation! lol
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Larry Fine
Fine Electric Co.
fineelectricco.com
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