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#51482 - 04/30/05 12:08 PM Homemade Shunt  
James Wells  Offline
Junior Member
Joined: Apr 2005
Posts: 3
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 12:36 PM Re: Homemade Shunt  
Sir Arcsalot  Offline
Member
Joined: Nov 2003
Posts: 127
Lynden, Washington
I wouldn't want to be around when that switch fails...!


No wire bias here- I'm standing on neutral ground.

#51484 - 04/30/05 12:42 PM Re: Homemade Shunt  
e57  Offline
Member
Joined: May 2003
Posts: 2,876
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.


Mark Heller
"Well - I oughta....." -Jackie Gleason

#51485 - 04/30/05 01:10 PM Re: Homemade Shunt  
James Wells  Offline
Junior Member
Joined: Apr 2005
Posts: 3
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 ~


#51486 - 04/30/05 01:15 PM Re: Homemade Shunt  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
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).]


Bob Badger
Construction & Maintenance Electrician
Massachusetts

#51487 - 04/30/05 01:24 PM Re: Homemade Shunt  
e57  Offline
Member
Joined: May 2003
Posts: 2,876
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

#51488 - 04/30/05 01:26 PM Re: Homemade Shunt  
James Wells  Offline
Junior Member
Joined: Apr 2005
Posts: 3
Mt. Olive,NC,USA
Thanks Fellows
I appreciate the Info...


#51489 - 05/01/05 12:23 AM Re: Homemade Shunt  
Larry Fine  Offline
Member
Joined: Feb 2005
Posts: 693
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.


Larry Fine
Fine Electric Co.
fineelectricco.com

#51490 - 05/01/05 12:35 PM Re: Homemade Shunt  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
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

#51491 - 05/01/05 04:45 PM Re: Homemade Shunt  
Larry Fine  Offline
Member
Joined: Feb 2005
Posts: 693
Richmond, VA
Oh, sure, bring doing it the right way into the conversation! lol


Larry Fine
Fine Electric Co.
fineelectricco.com


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