Our house has a 200 A main circuit breaker panel. (Pic 1.) It’s a General Electric panel that was installed in 1989, when the house was built.
I am in the process of installing a 120/240 V, 50 A receptacle in the basement. Today I ran the 6/3 wire to the main panel shown in Pic 1. I then noticed a problem… the neutral/ground bus bar inside the panel is full. (Pic 2. Pic 3.)
There are some small, unused slots in the neutral/ground bus bar I can use for my ground wire. But no unused lugs for my big 6 AWG neutral wire. (The existing neutral/ground bus bar only has two large lugs, and both are used.)
What should I do? Can I install a second neutral/ground bus bar in the panel? If so, how – exactly – do I do this to code? What AWG wire is required between the existing neutral/ground bus bar and the second neutral/ground bus bar? Can the second neutral/ground bus bar be screwed directly to the panel (to the right of the main circuit breaker)? Or must it be electrically isolated from the panel?
You can in fact buy additional bus bars for the panel. Since this is the main panel, the second bus bar should be bonded directly to the panel just like the first one. (I’m not sure if it also has to be directly connected to the service neutral, though.)
FWIW, you can double up grounds (of the same AWG) under one screw. But you can’t do that with neutrals. That might provide enough space without installing a new bus bar.
ETA: Further research reveals that the two bars do need a neutral jumper between them. The size will probably depend on the capacity of your service.
i install a grounding bar (holes for mounting on either side of enclosure grounding the enclosure also) in all breaker boxes and keep grounds and neutrals segregated. neutral is grounded at meter and not after. grounding bar is connected to a grounding rod.
This might be right or wrong depending on your area’s local practices. It essentially means that your meter socket is acting as your main panel and your actual panel is configured as a sub-panel.
If your 6 AWG wire is stranded, one trick is to separate the strands into two bundles, forming a Y. Then pick two adjacent smaller slots in the neutral/ground bar and put half the Y in one, and half in the other. Doubling up on the grounds may free up some space to get two empty adjacent ones.
That’s probably not technically up to code, but it’s not that uncommon to see in practice.
The official way to deal with this is to install a new bus bar, as friedo says.