Hello all, I was hoping someone here could point me in the right direction. I want to add a circuit to my home but my breaker box does not have enough holes in the Ground/Neutral bus bar to accomodate the circuit. I have room for 5 more breakers but due to a design in the box, a number of holes in the bar are not able to be used. I bought a ground bar extention, and it says I can put
2 #12's per hole, but when I asked people about using 2 wires per hole in my existing box (new square D) that uses the same size bar/holes, you would think I commited heresy! Something just does not seem to add up!? I realize that one wire per hole would be the ideal, but they all connect via the bar itself, but is this a safety issue? Any code number to back this up?
Suggest ( unless someone comes in that is more familiar with code than I, or can point to a reasonable explanation of why not ), to go ahead and double up some of the neutral wires on the buss........
Note that you shouldnt mix wires of different gage within the same lug terminal, nor should you mix stranded wire with solid.
However, I would definately advise against any doubling up of the bare ground wires.
If the bar is listed for 2 wires per hole, then go ahead and use it that way -- but I would not put both a white wire and a bare/green wire in the same hole (especially for the same circuit.)
If the existing bar doesn't say you can connect 2 wires per hole, assume that it can only take one wire, even if it looks exactly the same as the new extension.
If you run out of grounds, you might also put a split-bolt connector on the *big* bare ground wire that comes into the box. Connect several of your small circuit ground wires to it -- freeing up holes in the ground bar.
Well, the way I see it, this is because if a neutral connection fails, the connected load simply fails to operate properly and will likely trip a breaker due to voltage drop at the bad terminal, with any risk of fire from heating at the bad connection will be contained within the breaker box.....
Now in the event of a failed ground connection, this becomes a safety issue--as it creates an electric shock hazard if a short to ground develops on the connected load.
Of course preferred method would be to install a complete new distribution panel, or at least a second one next to the old, subfed from a large breaker installed in the existing one......
If the screw holding them both somehow comes loose, the ground wire could be energized by the neutral wire -- they will still be touching and presumably both lose connection to the panel at the same time.
It's kind of a contrived problem, but 2 wires in one hole is unnatural anyway.
Also, I don't think a neutral wire should be connected to an add-on ground bar because you don't really want the steel mounting screws to be carrying current all the time. The neutral bar is connected directly to the big white supply wires, the ground bar is not.
These people exist only to scare the crap out of unsuspecting homeowners like yourself. They always have this wild story ready about your screws suddenly flying loose all by themselves, and the wires just JUMPING out of the holes, all by themselves, and well, I'm sure you see the picture. Two questions for you:
1) Do you know how to -properly- run wires inside of a box??? Hint: the answer has to do with routing the wire so that it can't really go anywhere else *but* in the hole. This is done by your sizing and bending.
2) Do you know how to tighten down a set screw and then test that your wires are not going to pull out? No real hints on this one, sorry
If you can answer "yes" to both of those questions, then I suggest you trust your instincts and ignore the doomsayers. When their earthquake comes (the only thing that will rip your properly installed wires from their holes) then I dare suggest you are going to have some other problems to deal with, like maybe the entire power grid being destroyed.
At the very least, use the new extension holes for two wires each, just as it is labeled. Every new circuit I've wired for the last 30 years I've put the ground and neutral for that circuit in the same hole, and at last count (OK, so this isn't earthquake country) they are all working just fine. But then again, I know how to tighten down a set screw and to size and bend two wires so they fall into the hole just about all by themselves.
Please ignore any such advice. There are very good reasons for the way the code is written. Failure to follow it not only increases you chances for disaster, but it also may mean your insurance will be denied if you do have a problem. Of course if you don't wake up you won't notice.
(getting out of bed in the morning "increases you chances for disaster")
There ya go. "Doomsayer 101". Folks like this believe that wires just up and loosen their set screws so they can jump out of the holes and burn your house down. It's disgustingly condescending, don't you think?, to be talked to like a child? Reminds you of the tease for your local newscasts during ratings sweeps weeks: "Next at 11, TEN THINGS around YOUR HOUSE that could KILL YOU!"
NEC 110-14(a) of the states in part that: "Terminals for more than one conductor and terminals used to connectaluminum shall be so identified." NEC
110-3(b) requires that: "Listed or labeled equipment shall be installed,used, or both, in accordance with any instructions included in the listing or labeling." The listing and labeling ofterminals includes the conductor size, the number of conductors, and any combinations of conductors that areallowed to terminate in a single lug. This information may be marked directly on the terminal or may be included inmanufacturer's information located on the equipment, such as a panelboard label.The instructions in a panelboard may allow multiple wire terminations on a neutral bar terminal. However, mostpanelboard manufacturers only allow multiple equipment grounding conductors in a single terminal. Groundedcircuit (neutral) conductors are usually limited to one wire per terminal. Most grounded branch circuit (neutral)conductors carry the full circuit current while the circuit is in use. The regular heating and cooling effects ofvariations in branch circuit current flow cause expansion and contraction of the conductors and can cause doubled-upneutral terminations to loosen in the lug. Equipment grounding conductors do not carry any current during normalbranch circuit operation. The installer must read the manufacturer's installation instructions included with apanelboard to determine if the terminals are approved for multiple neutral conductors and/or multiple equipmentgrounding conductors.
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Probably what he purchased was an "equipment grounding bar". Two equipment grounding conductors (bare or green wires) would be permitted to be terminated under one screw in that case. The neutral (white) wires need to be terminated with only _one_ wire per screw. Also, if he takes a closer look at the existing neutral bar he should be able to find a way to use the holes that he says are inaccessible.
No, "I-Shit-fer-brains", the majority of us in this NG try to get the correct info to folks so they can make safe electrical installations. Whether or not those folks heed that advice is _their_ business, but at least they have the correct info. GET IT?
Now you're just showing your usual ignorance. The wires don't have to "jump out of the holes" to cause a problem. A loose connection is enough to cause problems. I believe others have covered the reasons why a neutral wire needs to be terminated by itself, besides, discussing _anything_ electrical with you is a waste of time.
Geez, what a moron.
Well, that pretty much rules out any discussion of torque limiting screwdrivers or wrenches.
That's why this is your theme song Tomi Boy:
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unfortunately, anyone taking your electrical advice will most likely hear it too.
Now THAT's the "Mr. Practical", Tom Pendergast who we know sooooooooooo well, practically stupid, that is.
That's funny, just SIX MONTHS AGO you tried to claim that you had 20 years in the trade (snicker). Why are you trying to come off like you're an Old Salt? We all know that you are a self-appointed internet armchair lesstrician who took a Sally Struthers "get your degree" electronics course
20 years ago, found your electrician's license in a box of CrackerJack, and somehow arrived at the conclusion that you are actually a bonafide electrician. I'd give you a week doing real electrical work before you either seriously injured/killed yourself/others doing some stupid shit or got pummeled by other electricians after you repeatedly endangered their lives.
Using your weenie electronics tools? BRAHAHAHAHAHAHA. YOU'RE A HACK TOMI BOY. SSDD with you Tom "Firebug" Pendergast.
No, it doesn't SAY that, it SAYS that 2 neutrals are NOT permitted. You want to nitpick over code wording, prepare to be hoisted on your own petard.
So if you have 1 ground and 1 neutral in a hole, there is only one wire subject to "expansion", the ground wire in inert, it is "part of the furniture", for all intents and purposes it is doing absolutely *NOTHING* as far as effecting the physical makeup of the connection. A ground and neutral in the same hole *W O R K S*.
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