Ran out of grounds/neutral slots in my main breaker box.

[lzicc]

I installed a 50 amp sub panel in a garage and ran #6 aluminum wire to main breaker box to find out that I am out of openings on the ground/neutral bar. This is an older Murray box and only has 1 bus bar for both neutral and ground.

What I was going to do was double tap one of the existing openings that currently has 1 - #6 ground from a 220 line that is for my central ac on the bar which large enough opening to hold 2 #6 wires in it. I was going to then run that #6 wire to a small ground bar that I purchased. Then from there I can run both my #6 ground wire and my #6 neutral wire to new small ground bar. It seems like that might be ok to do, but wanted to get others opinions. If that isn't an option, I may need to upgrade the box, but I don't want to do that at this time.

 

[radioman]

you should be able to add on a grounding bar to have more room. they have extras at home centers. what i do is i combine couple or several ground wires and twist them together and put it in one lug. the whites i keep them separate (dont combine whites - ever- lugs on neutral bar.

 

[lzicc]

All the large enough openings on the ground the bus bar, which there is only 6, are being used for 220 grounds. So I can't double up the #6 neutral from the sub panel. The ground I can, since that is allowed, but neutral is not. That is where I am stuck.

I do have a second ground bar, just not sure of the correct way to connect it to the existing ground bar and since this Murray box is old, I just picked up a generic bus bar, so it will not be able to be mounted to the breaker box using pre tapped wholes since I can't the one specifically for this box. I'll have to use sheet metal screws to attach it.

 

[Budweiser John]

you should be able to add on a grounding bar to have more room. they have extras at home centers. what i do is i combine couple or several ground wires and twist them together and put it in one lug. the whites i keep them separate (dont combine whites - ever- lugs on neutral bar.

I think you contradicted your self. Only one wire under one lug bo matter where. If the panel in question is a sub panel and down stream from the main service entrance the neutral and grounding conductors must be separate at the sub panel. I.E. the feeder from the service entrance should be 4 wire and the sub panel have separate bus bars, one for the nuturals and one for the ground conductors serviced by that panel.
The natural and ground conductors can only be bonded at the main service entrance.
B. John

 

[lzicc]

You are correct. From the sub panel, I have 4 wires, 2 hots, 1 neutral and 1 ground. The neutral and the ground have their own bus bars in the sub panel. Those feed over to the main main panel. The main panel has only 1 bus bar for both neutral and grounds. There are not any large enough openings for the wire size I am using. What I thought about doing was double tapping one of the existing 220 grounds with a #6 piece of wire and run the other end of that wire to a new, 7 opening ground bar to complete that part of the ground/neutral circuit to the main bus bar. That would leave me 6 opening in the new ground bar to attach my ground and my neutral that is coming from the sub panel. It seems like that would work, but doesn't feel right to me.

 

[RNeumann]

You don't need to "double tap" from one bus bar to the other for the ground. The box itself conducts from one to the other and is grounded. As noted above the ground and neutrals should be separate and the neutral bar shouldn't be indirect contact with the panel box.

As a note- you know you can place multiple wires in one bus bar hole/slot. It's interesting that it's run out of space. That sends a red flag up.....

 

[lzicc]

RNeumann, in the sub panel, the neutral and ground are separate. In the main box, there is only 1 bar and both neutral and ground go to the same bar. If I mount the second ground bar in the box, you are correct about the box grounding once it is mounted, but since I have a neutral coming from the sub panel, I would need to put that in the new ground bar also along with the ground coming from the sub panel. Since the the original grounding bar is bonded with the box, in lack of better words, both neutral and ground are on the same circuit you could so in theory it should work. I've read about running a feeder from the new ground bar to the original ground bar.

The reason it is out of spaces is one, the bus bar handles both ground and neutral, when the newer boxes usually have 1 neutral bar and 1 bus bar. Also, some of these circuits have tandem breakers in them. I do have 2 open spaces, but they will only accept up to 10 gauge copper.

I do need to upgrade this box to a new one and I wanted to put that off for now, but I may not be able to. The big issue with swapping out the boxes is I need to have the power company pull the meter so I can swap out boxes, get it inspected, then have the power company put the meter back in. I live in the house, so I don't have the luxury of waiting for the inspector and power company. I could swap out the box in the matter of hours, but the inspection is what could hold me up.

 

[LD1]

Got any pics of your current main panel?

 

[lzicc]

Here are the pictures. The one is diagram on the door of the box.

Got any pics of your current main panel?

 

[RNeumann]

RNeumann, in the sub panel, the neutral and ground are separate. In the main box, there is only 1 bar and both neutral and ground go to the same bar. If I mount the second ground bar in the box, you are correct about the box grounding once it is mounted, but since I have a neutral coming from the sub panel, I would need to put that in the new ground bar also along with the ground coming from the sub panel. Since the the original grounding bar is bonded with the box, in lack of better words, both neutral and ground are on the same circuit you could so in theory it should work. I've read about running a feeder from the new ground bar to the original ground bar.

The reason it is out of spaces is one, the bus bar handles both ground and neutral, when the newer boxes usually have 1 neutral bar and 1 bus bar. Also, some of these circuits have tandem breakers in them. I do have 2 open spaces, but they will only accept up to 10 gauge copper.

I do need to upgrade this box to a new one and I wanted to put that off for now, but I may not be able to. The big issue with swapping out the boxes is I need to have the power company pull the meter so I can swap out boxes, get it inspected, then have the power company put the meter back in. I live in the house, so I don't have the luxury of waiting for the inspector and power company. I could swap out the box in the matter of hours, but the inspection is what could hold me up.

Ok easy enough. The main panel can accept the second bus bar and that bar should be grounded directly to box. It is ok (by code) to commingle neutral and ground in the main panel bus bars- however some would still separate the grounds and neutrals for future diagnosis and looks.

If you wanted to add a jumper between the two bus bars you can. It is a nice thought and shows your desire to do the best job possible and be conscientious about your work.

The separate ground and neutrals in sub panels helps with diagnosis. I know it's a bit strange having to run the extra wire and have separate locations for the neutral and ground in sub panels. But it is code.