Bonding at panel attached to generator transfers switch

**Michael Thomas** · 05-24-2011, 02:33 PM

Service panel w/ adjacent "load-side" panel used to contain breakers for circuits being transferred. See attached pictures.

Service equipment is at left, additional panel at center, transfer switch is at right,

Bonding jumper is installed in center panel.

Is there a reason inherent in the use of this panel with a transfer switch which requires neutral to be bonded to ground?

Don't see many of these, and any other comments or observations about this setup are appreciated.

- Thanks

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**Michael Thomas** · 05-25-2011, 05:36 AM

Anyone?

Roger Frazee · 05-25-2011, 08:16 AM

Originally Posted by Michael Thomas

Anyone?

Hi Mike

Have to make a quick reply, so here goes ... that bonding jumper should be removed from the center generator panel. Emt is serving as your equipment grounding so no bond in that center panel or neutral current will use the emt and bonded metal to return to the service equipment and then the source (transformer). The transfer panel appears to be fed from a double breaker in the service equipment so it is out of the picture as being the service equipment in itself. Essentially you have 4 wire feeders from the service equipment to both the transfer panel and generator panel when considering the EMT so no bonding to neutral in either of those panels. You also need four wires to the generator. That's how I see things but I wouldn't take my analysis to the bank. I don't believe the auto transfer switch shown switches the neutral so that the generator becomes separately derived.

Would be best to have the installation checked by a qualified person IMO but based on what I see there is no way you would want that bond in the center panel.
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