I'm adding two new outlets to my circuit breaker panel. I've got the room for the additional breakers in the box but the neutral bus bar has no more room for the neutral and ground wires required. Is it permissible to put more than one wire per set-screw hole on the neutral bus bar? Some sites I've researched say yes, others say no. If no, what are the options besides replacing the whole circuit breaker panel?
TIA,
-- Bobby G.
No.
Get a bus bar kit from your distributor. Install in panel, there will be predrilled/ tapped holes for this. Connect regular bus bar and added bus bar via the larger set screw holes intended for this purpose. Use short section of #4 or #6 bare copper to connect. Should take half an hour and cost under $20. HTH
Joe
t the room
ions besides
yeah i added a bus bar to the home i sold because a bunch of bus bar screws were totally frozen in position, used bus bar from home depot it passed middle group inspection after home inspector insisted re inspection because original sticker signature had faded,
i hope the fellow who bought my home has even worse hassles when he sells my old home, it would serve him right
You can double up or maybe even triple up GROUND wires (depending on brand) , Neutrals are one per hole. Look at the panel label to see about the grounds. Don't pull of any neutrals if the power is on. Bad things can happen. Trip the main. Certainly adding supplimental bars is a better way to go but don't put neutrals on suplimental bars, only grounds. If you put a neutral on the supplimental bars you are putting circuit current through the metal can and the green bonding screw. (that is 250.6 for you code guys)
roomIfor the additional breakers in the box but the neutral bus bar has no more>room for the neutral and ground wires required. Is it permissible to put more than one wire per set-screw hole on the neutral bus bar? Some sitesdI've researched say yes, others say no. If no, what are the options besidestreplacing the whole circuit breaker panel?gnTIA,"g--tBobby G.
I have no problems putting more than one wire into a hole in a bus bar and tightening down a screw onto them. It has got to be more solid and safer than a wire nut. However, if this is an old box with screws that you wrap the wire around under the screw head, don't do it. Only one wire per screw head.
Somewhat repeating gfretwell - ground wires can be doubled up but only if the label indicates that is permitted.
Neutrals may NOT be doubled up - NEC 408.41
In a service panel you can add a ground bar which the label indicates is acceptable and move ground wires to it. In a subpanel that doesn't help.
ONLY IF YOU KNOW WHAT YOU ARE DOING - you could take a neutral from an A-leg circuit and a neutral from a B-leg circuit, wirenut them together with a single wire to the neutral bar. It is easy to do this wrong.
The issue is not the security of the connection. It is that when you would disconnect one neutral you would be opening the other one too if they were doubled up.
Can't you also combine two A-leg neutrals, as long as the pigtail between the wire nut and the neutral bus is sized to carry the sum of the two circuit currents?
Dave
The panel label should have the information that you need. Usually you can double or triple the ground wires together. The neutral wires must be by themselves. As others have suggested it is possible to add a ground bar to the panel.
Thanks, Joe. That's what I thought when I saw the two front-facing threaded screw holes on the frontmost bar. At first I thought they were empty set-screw threads but on closer inspection, that's where two existing bus bars are connected. I'll check with the local supply house after I record the box model number and take some photos to show them. I recalled reading somewhere that two wires to a hole can lead to intermittent neutral problems and that's why I asked.
-- Bobby G.
My inspection sticker turned out to be a forgery! The son of the original owner called me to confess his father's sin after they had some big fight. Not much I could do about it, though.
What goes around, comes around.
-- Bobby G.
That explains the confusion.
Shocking!
Not sure I understand this. This is a very old (well circa 1981) panel. I have a photograph but I think the Usenet police forbid posting same here. It looks like a supplemental bar would screw into the two existing bars and wouldn't contact anything except the existing bars. This is old, ungrounded wiring. The panel was a "heavy up" added so that the buyer could qualify for an FHA sale. Next time I go downstairs, I'll copy all the important info.
-- Bobby G.
I wasn't going to do the pigtail/wire nut route. I'd rather pull the whole box and put in one with a higher capacity and more features than start spaghetti-ing up the box with wire nuts. Well, that's not exactly true. But I certainly agree that two wires to a hole couldn't be any *worse* than putting two neutrals into the same bus bar hole. BTW, it's not a screw head type box. There are setscrews that lock wire into holes a little bigger than 1/8" in diameter so there's more than enough room for two #12 wires. Just doubling up a few would give me enough free spots for the neutrals I need. But the best solution seems to be adding a third bus bar, if I can find one.
-- Bobby G.
Can you explain further? I am not sure why two neutrals to a hole is a bad idea, just that it's not code. Aren't all the neutrals all interconnected at the bus bar anyway?
Thanks!
-- Bobby G.
From: "bud--"
I will check the label shortly and report back. I think it's a Square-D circa 1981.
Well, at least I can be thankful I'm not completely senile. I do recall reading one to a hole *somewhere* during my life. IIRC, it was because the setscrew wouldn't hold two wires as securely as one, but it seems there are other considerations as well.
It's a Square D QOC-20MW (on the cover label) but a QO8W-20M100-5 on the panel label. There are three diagrams on the label and the one that appears to apply shows three levels of neutral bus bars with arrows pointing to the center of the center bar. One arrow says "Box bonding when required" and points to the very center of the bar at a O in between two X's. The other says "Ground when required" and points to the innermost left setscrew on the center bus.
v [ O O O O X o X O O O O ] ^
(The O's are set screws There's also an abbreviation S/N next to a circle that's drawn inside the lines of the third bus bar. On the other two drawings where there are only two bus bars, the circle is outside the bus bars.)
Not anything written on it that would seem to shed light on the "more than one to a hole" issue.
The box label has 4-81 in the lower left corner and the box's forged inspection label is dated 6/82 so I assume this box is 25+ years old.
-- Bobby G.
If you can find a kit that piggybacks on the neutral bus you can connect neutral wires to it but most supplimental kits just screw to the enclosure in factory tapped holes. That is fine for ground wires but you don't want neutral wires on that kind of bus. It puts circuit current through the metal enclosure.
I see. The bus bar that I am hoping to find should be a piggy back type that screws into the existing bus bars, essentially adding another "tier" of holes and setscrews. It doesn't connect to the panel enclosure, but seems to be electrically isolated from it. It would seem that the screws that hold the new bus bar to the old two would be able to carry a lot of current but I believe I will take a large piece of wire to connect the two bars as advised previously. I'm just hoping I can find something to fit a 26 year-old circuit panel.
-- Bobby G.
You posted the relevent information. The model number of the panel and the part number of the neutral kits listed for it should be all you need if you go to a real electrical supplier. The Home store *may* have it but you will probably have to figure out which one it is yourself.
You can poke around on the SqD web site to see what they have
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