I have a 10/2 run from my main panel in a shop outside to a subpanel at a multi flag pad. The subpanel has three breaker runs off of it (Recep, lights, etc.)

I was hoping to place a GFI breaker in the main panel to protect the entire subpanel but with the combined neutral and ground at the subpanel the GFI won't work.

Is there a way to go with (1) GFI at the main box for the entire sub panel or do I have to go to the expense of three seperate GFI's at the subpanel to protect the final product?

 

NEC prohibits ground & neutral bonded together in a subpanel. You must remove the neutral bonding screw (runs through the neutral bus into the metallic box), install a ground bus directly to the box, first sanding all the paint off the spot where the bus will be installed, then separate all your individual neutrals and grounds. Bround buses can be had at Leow's or Home Depot for about $4.00 or so. If I understand your post correctly, a GFCI breaker will no longer be a problem for you.

Juice

 

I agree on the seperation of the neutral and the ground if I put a GFI breaker in the main panel. I just got off the phone with my county building inspector. Even though this application is outside and not under his juristriction, I have been working with him because the panel in question is on a public park. I want to make sure it is NEC compliant and all applications are UL approved.

While he plans a visit to review my application he believes the panel at the flag pole pad does not fit the NEC description of a "subpanel" because it is not in an enclosurein the same building as the main panel. The panel is fed from a breaker at the main panel but he feels the three panel breakers are acting as switches and not as breakers. (one turns off pad lights, one turns off shop lights, one supplies a recep at the pad.

He said NEC calles for the RECP only to be GFI protected and not the pad lights. While he is not opposed to making the whole panel GFI protected at the main panel by using a GFCI breaker, the pad lights have a photo sensor and dimmer switch inline and he though the GFI breaker might not work well with the dimmer switch.

Comments?

 

First of all, there is no NEC description of a "subpanel". To my knowledge, the word "subpanel" doesn't even appear in the NEC.

If the breaker is providing overcurrent protection, then it is an overcurrent protection device, not merely a switch. One test of this would be to ask you inspector if it's okay if you substitute ordinary switches for the breaker. If the breaker in the main panel is larger than 20 amps, or if there is any wiring out there less than 12-gauge, the answer will be no. But perhaps the breaker in the main panel is 20-amps and you are using all 12-gauge or larger wire. If so, please let us know, and I would recommend that you do in fact use simple switches.

I believe that the photo sensors and dimmers will probably be okay on GFCI, but I can't promise you that.

Finally, if these are merely switches, then you most certainly cannot interconnect the neutrals and grounds out there. That's for sure!

 

Run to the box is 10/2. Rest is either 10/2 or 12/2 depending on application. All breakers in box are 15 amp. Main box is 20 amp at the moment. I already bought a 20 amp GFCI breaker. I will probably seperate the neutral and ground and go with the GFCI anyways.

I already have everything wired so I will stay with the subpanel configuration. I went with the subpanel box because I have three breakers in the box:
1-feeding a recep
2: feeding photosensor/dimmerswitch/flag lights
3-goes back to the shop, through the light switches, and then to the outside security lights. That one is a long story but because the site is used at night by astronomers, I needed a simple way for them to shut off the outside lights without giving them a key.

Finally: "Finally, if these are merely switches, then you most certainly cannot interconnect the neutrals and grounds out there. That's for sure!"
I ask why? At the moment I have a regular breaker at the main panel and everything is wired and has worked fine for months.

 

If you interconnect the neutral and grounding outside the main panel, then current will flow on both the neutral and grounding wires. You never want current flowing on the grounding wires except in the event of a fault.