Question about my circuit-breaker box

grounding bar or lugs should have only bare copper wires only. as long as the connection is good, it doesnt matter how many grounds per lug. neutral bar should only have white wires, not doubled up. breakers or fuses should have only black or red wires, not doubled up.

So you're saying that I really need two ground-busses - one for bare copper ground wires (doubled up okay), and one for neutral white wires (but not doubled up)? I think I can do that.

Of course none of my black (hot) wires are doubled up. That seems common sense, at least to me.

Thanks

Jethro

About 3 months ago, being an electrician, I got a call to repair what electrician's call a "fire job".....where the Fire Department was called because of an electrical fire. I talked to several witnesses who said that where the fault occured in the circuit flames were shooting 20 feet. Even if that was an exageration it was still shooting some serious flame. Fortunately it was outside. Must have been a pretty good show since it was dark when it happened. While fixing the circuit I noticed that the equipment ground (bare) and the neutral (white) wires were landed under the same screw on the busbar (as were many others). The neutral wire was burnt about 12 inches. The connection was loose and corroded and had a very high resistance. The resulting current during the fault was under the 20 amp breaker limit, yet large enough to cause some serious fire damage. So ,Wade, I don't know where you are getting your numbers, but you are way off. It happens more than you know. All the more reason to have electrical work done by qualified people. Something that gets installed by hacks might take 5, 10, even 15 years to burn.

My understanding was that you need keep the ground-buss and the nuetral-buss separate in sub-panels, but that you can mix and match in the main service panel, because that's the one and only place where ground and nuetral are supposed to meet. (which explains why service panels come with only one buss, but doesn't explain why there's never enough holes in that buss.)

Further, I was under the impression that whether or not you can end two wires in any one spot was a function of whether the connector in question is rated for multiple wires. Granted that most of them aren't. It SHOULDN'T make any difference whether the wires in question are nuetrals, grounds. Either the connection method is reliable for two wires, and specified that way, or it's not. (I can see not wanting to mix nuetrals and grounds, on the theory that the pair might come loose from the buss, but not from each other. That would be bad.)

Likewise, breakers may or may not be rated for two wires under the screw. I'd expect most not to be, and any that are should be labled to say so. I'll confess that I can't think of all that many reasons to WANT to put two wires under one breaker.

--Goedjn

All true except the NEC does not allow neutrals to be doubled up. The label on the panel will indicate if multiple wires are permitted elsewhere. Tom's post has the relevant code sections.

bud--

The new breaker I got for a square D QO panel is labeled.

Goedjn The reason that some terminals in neutral buss bars are OK for two Equipment Grounding Conductors (EGCs) but not two Grounded Current Carrying Conductors (neutrals) is that since neutrals carry current under normal operating conditions the two neutral conductors might well be expanding and contracting at different times and to different degrees. That would cause the connection to loosen over time. EGCs on the other hand only carry current under fault conditions for a very brief time so sharing a terminal that is listed for two conductors is permissible for EGCs but not for neutrals.

This for the ungrounded conductor, "hot", and once again, you must follow the manufactures instructions, per code.

later,

tom @

Hiya

I have been away and am just now reading the various posts on my query.

Thanks for your info. I don't know if my panel is a sub-panel of a main-panel. You see, I live in a manufactured home that has a big service panel inside the home that services everything within the home. Then there is a second panel outside the home (on the side, under the electric meter) that services mainly everything in a separately built large garage. That box has a 200A main that, when tripped, cuts off current to the other box in the house. That could make this outside box a main service box, but if I didn't happen to have a garage, then I guess the inside box would be the main.

Further, I had an electrician wire a porch addition I had done, and he connected to the outside box. Further, I had another electrician install a surge protector to protect my house, and he connected to the same outside box.

All I wanted to do was add two 15A breakers to the outside box to handle two new outlets I added - (1) for my porch window A/C and (2) for my computers/printers. When I added the two breakers to the outside box, it was then that I discovered the lack of sufficient buss connections for the ground and neutral wires. I also discovered at that time that the electricians I mentioned above had doubled up on the bus connections for their work, and so, I assumed that I could too. Now I see that is not entirely true, and since not true, I thought I should add another buss to enable single wire connections on all the busses. I have bought a buss, and #6 wire to connect it to the present buss, and am waiting for news group comments before I proceed.

Thanks

Jethro

The outside box with the meter is the main service equipment. There must be four wires in conduit feeding the inside box....2 hots, 1 neutral, and one equipment ground. The neutral and the equipment ground must be separated in the inside panel. If you look under the house where the inside box is located, you should also notice that there is a solid bare copper wire that is attached to a lug that is connected to the metal frame. That wire must also be connected to the equipment grounding bar. Also your range and dryer, if electric, must be 4-wire.

In the outside box, if you mounted the new equipment grounding busbar to the metal cabinet via the factory mounting holes with the provided machine screws, that should be sufficient. No harm in jumping over to the existing busbar though.

Thanks again everyone. I think I have a clear view now as to what I have, and what I have to do.

Jethro