ECN Forum
Posted By: George393 EGC and Manual Transfer Switch - 04/12/10 04:06 AM
A customer requests an addtional circuit (3 outlets) in a stand alone garage.

She has an outside 100 AMP disconnect at the entrance. From there the feeder goes direct to the oposite side of the house and terminates at a Ronk 100 AMP manual transfer switch (for a portable generator hookup).

EGC and all neutrals from the single house distribution panel and the stand alone garage distribution panel are bonded together inside the Ronk manual transfer switch. The house distribution panel and the stand alone garage distribution panel have egc and neutral seperate as required in each panel.

House panel is 125 AMP service. Stand alone garage panel is 100 AMP service.

I cannot find a code section on this.
Q - Can both these two distribution panels be bonded together (EGC and neutral) at the same location inside the Ronk manual transfer switch?
Q - If they can be does the 1st bond of neutral and ground at the outside service entrance disconnect (on the other side of the house) cause a problem by being a second EGC and neutral bond?

Thanks.
Posted By: gfretwell Re: EGC and Manual Transfer Switch - 04/12/10 07:25 AM
Short answer, no if the transfer equipment is not switching the neutral. You can only have one main bonding jumper in the system at a time.
Posted By: George393 Re: EGC and Manual Transfer Switch - 04/12/10 10:37 PM
Thanks Greg
Posted By: sparky Re: EGC and Manual Transfer Switch - 04/13/10 12:16 PM
well one can see the confusion in possibly having to add a GEC to the stand alone garage because it exceeds a single circuit here, and the specture of a SDS introduced.

In fact, many genny manufaturers provide a lug for a GEC to be made off it as well....

~S~
Posted By: gfretwell Re: EGC and Manual Transfer Switch - 04/13/10 02:54 PM
The real issue is not the ground electrode. It is the bonding jumper regrounding the neutral. As long as you keep the concept in mind that you can only have one bonding jumper in the system at any time and coordinate your transfer equipment and whether or not your generator is bonded you will be OK. The EGC system should always be connected together. It is the neutral that you switch or not.
Posted By: sparky Re: EGC and Manual Transfer Switch - 04/13/10 10:53 PM
well said, an a very good general concept to keep in mind Greg

~S~
Posted By: gfretwell Re: EGC and Manual Transfer Switch - 04/14/10 12:44 AM
I didn't invent it. This was the way Jim Pauley on one of his road shows (a Soares pitch) explained it and it made perfect sense.
Posted By: sparky Re: EGC and Manual Transfer Switch - 04/14/10 12:15 PM
Well Mr. Pauley saved himself lots of code-speak, reminds me of when i was told 'If it's metal, and doesn't move, bond it'

~S~
Posted By: George393 Re: EGC and Manual Transfer Switch - 04/14/10 02:12 PM
Between Soars book on grounding and Mike Holts grounding and bonding book - which would you rather have in your library?
Posted By: gfretwell Re: EGC and Manual Transfer Switch - 04/14/10 03:59 PM
Why wouldn't you bond things that move?
That's why they make braided bonding straps and stranded green wire wink

Maybe I spent too much time on the load side of the plug cap.
We bonded everything metal. Even a hinged cover got a bonding strap.
Posted By: Yoopersup Re: EGC and Manual Transfer Switch - 04/15/10 12:08 AM
Soars by a long shot
Posted By: gfretwell Re: EGC and Manual Transfer Switch - 04/15/10 07:07 PM
With all due respect to Mike, I say Soares too.
Mike may do a good job of translating code to English but I speak code fairly well.
Posted By: SteveFehr Re: EGC and Manual Transfer Switch - 05/03/10 05:28 PM
One potential issue is that most portable generators in the US have an internal neutral bonding jumper, that once connected to the building electrical system, creates a parallel neutral return path through the grounding system.
Posted By: gfretwell Re: EGC and Manual Transfer Switch - 05/03/10 05:32 PM
Portable generators are not really intended for hard wire connection to premise wiring. Usually there is a procedure in the installation guide to lift that bonding jumper.
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