View Full Version : Grounding Main Load Center

June 11th, 2004, 04:46 PM
I have a home that was built in í74. It has the original Bryant load center (150 amp service). I have added circuits when we added a home office in the basement and a couple of other because of overloading. My question is when I open the panel it has two grounding bars. One has the natural wire connected to it from the main wires coming from the service meter. The other grounding bar is connected to a bare ground wire thatís connected to the grounding rode. It looks like on either grounding bar there is a mix of (white) neutral wires and the bare ground wires from the circuits. Are the two supposed to be seprate..one having only the bare ground wires and the other having the neutral (white) wires? Both the ground bars are next to each other. Is this correct or should they be separate from each other. Or has the codes changed since this home was built? I would like to add an Arc fault circuit breaker to the two 15-amp breakers that service the 4 bedrooms on the top floor. I donít know if that would be possible giving the grounding in the service panel. Thanks.

June 11th, 2004, 04:58 PM
That sounds right to me. The bar that has the neutral connected to it likely has a "bonding screw" installed, mechanically and electrically connecting that bar to the "can" of the panel. The other bar, likely an accessory ground bar, is also screwed into the sheet metal can. It's just coincidence that the grounding electrode conductor (wire to ground rod) happens to be connected to this bar. If you don't have any main disconnect ahead of this panel, the grounds and neutrals don't need to be separate. When buying arc fault breakers, the Cutler-Hammer 'BR' series are cheaper than the original Bryant, and are UL listed for use in Bryant and Westinghouse brand panels.

June 11th, 2004, 05:18 PM
Thanks for your help. Now if I can only fine someone who carries a double pole AFCI with and independent trip, the bedrooms share the neutral. The retail price on the Cutler-Hammer website is $313 US dollars! The retail list for a single pole is $162, were do they get these prices!

June 11th, 2004, 05:30 PM
When I inquired last month, Cutler Hammer was the only manufacturer making double pole 15 and 20 amp arc fault breakers. The retail prices on the website are about double what you actually pay at the supply house. The double pole arc fault breakers are dog-gone special, so you pay an extra special price! :D

June 11th, 2004, 06:32 PM
thanks for your help!

June 11th, 2004, 06:33 PM
You have a similar problem as me. My second floor (4 bedrooms, a bathroom, and laundry area) is powered from a 15A multiwire branch circuit. I've broken off part of one segment and have a 15A arc fault on that segment. I think you'll find it cheaper to find a way to get a new cable to the second floor and then rearrange things so that you have two circuits that aren't the multiwire flavor.

You can replace the double pole with a single pole breaker and then tie the red and black wires together. This will make one huge 15A circuit. Then, find a place to break that circuit about in half and run a new 14-2 AF circuit to some receptacle box in that split off segment (pick the easiest box to run the new cable to).

You can get single pole CH BR arc fault breakers at Home Depot for $30. They can order breakers for you too, or you can go to an electrical store, but I'll bet the best price you'll find for the double pole arc-fault breaker will be in the $120 to $150 range. I can deal with some sheetrock pain-and-suffering in order to save $100.

June 12th, 2004, 09:31 PM
Couldn't agree more with previous posts regarding scrapping the 2 pole AF idea. No matter what documentation manufacturers provide, 2 pole AF breakers nuissance trip all too regularly. If it is possible, re-feed the bedrooms on 2 conductor. Also, be careful about the abandonded leg of the 3 wire circuit in the panel. Putting the black and red wires under the same screw on the breaker (double lugging) and also because the neutral will be pulling the additive of the 2 circuits' current, should someone later add to this unused leg.

Be sure to completely remove the old bedroom circuit before refeeding it, or pop. Also, be sure you remove the neutral of the dedrooom circuit from the old 3 wire circuit because the AF breaker will falsely trip if the neutral is shared, much like a GFI outlet that uses a protected neutral and another unprotected neutral.

consider running conduit on the outside of the house into the basement to refeed the bedrooms.

June 13th, 2004, 12:51 AM
2 pole AF breakers nuissance trip all too regularly
On what do you base this? While the expense of a 2 pole AF breaker often precludes their use, the nuisance tripping assertion seems unfounded. Seriously, Paul, have you used that many 2 pole AFCI's to have concluded they nuisance trip any more than single pole AFCI's?

consider running conduit on the outside of the house into the basement to refeed the bedrooms.
This has to be the absolute least desirable and ugliest way to refeed a circuit.

June 13th, 2004, 01:46 PM
Granted, conduit is not pretty in residential, but is definitely the easiest/quickest way to get to a top floor from the basement. Also, I should note that I am used to city construction, which is all old brick homes, and the conduit doesn't really stand out as much as it would on suburb-style sided homes.

Prior to the requirement for the AF breakers, I usually ran a multicircuit to the bedrooms, since they almost always share a common wall. When the AF reqt was enforced and we had to trim-out these projects to provide AF protection, I was floored at the cost for the multi-circuit AF breakers, but installed them anyways. One project in particular was a small 8 family apt complex, and we ended up having so many false trips, the landlord made us replace the runs in 2 of the apts. No call backs since. Never again am I going to use a multiconductor for AF runs.

In talking about this with others, this seems to be a pretty common problem, and I have been told that the only remedy is the new 14-2-2, which eliminates the shared neutral; but then you wouldn't need the multipole breaker.

All I know is that I will NEVER install a multiconductor circuit requiring AF breakers because of this past experience and the outrageous cost. I am only speaking from past experiences, sharing my knowledge to help save someone else my headaches. If you have positive experience with the shared neutral breakers, then continue using them. I will never go near them again!

PS the only panels we install are Cutler-Hammer, and the breakers in question were the Eaton BR series. This is what my negative experience is with; I have no first hand knowledge of another manufacturer's product, but I believe Eaton holds the patent on these breakers, so they are all probably made by them.