Bonding ground to neutral in main panel

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Old 02-23-19, 08:28 AM
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Bonding ground to neutral in main panel

I noticed that the ground and neutral bus bars are not bonded in my service panel...see attached pic. Half the circuits use the neutral bus for both ground and neutraln and the others use ground bus for both ground and neutral. Should I jump the two busses with either#6 or #8?

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Last edited by PJmax; 02-23-19 at 06:21 PM. Reason: ray: Add image. pj: labeled image
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Old 02-23-19, 08:47 AM
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I don't see a ground bar at all, but I see two neutral busbars that are internally connected. I do not see a box bonding screw or jumper, but it could be I just don't see it. I'd check the label inside the panel door for the panel illustration to see exactly how and where the box bonding is to occur. I also see a few issues of both neutral and grounding conductors in the same hole on the neutral bus, but considering the age of the panel, I know this was quite common around the time this panel was installed.

Overall, your panel is a little on the sloppy side. I wouldn't allow a panel to be left looking like that.
 
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Old 02-23-19, 09:15 AM
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You are right..thanks very much. I didn't see the internal bond between the busses behind all of the wires.

According to the label, the left side bus is to be bonded about Midway when required. Guess the only work to be done (assuming I'm ok with the messiness) is to bond the bus to the box with a green screw?
 
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Old 02-23-19, 10:06 AM
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Guess the only work to be done (assuming I'm ok with the messiness) is to bond the bus to the box with a green screw?

The screw doesn't have to be green, but it's easier for inspectors to find it when it is green. You could also bolt a small ground lug to the panel box and connect the lug to either neutral bus. I believe a #8 or #6 would work for bonding purposes.
 
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Old 02-23-19, 11:40 AM
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Another thing is neutrals are not to share the same hole with grounds. Usually panel specs only allow one neutral per hole and grounds can be two to a hole. Are you sure there are no screws through the bar into the panel for bonding? Check for continuity between the panel and the bars.

Edit: I now see CasualJoe committed on the neutrals and grounds in same hole. Didn't mean to pile on.
 
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Old 02-23-19, 06:22 PM
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There is a location in both bars for a bonding screw. I circled both of them.

Looks like an awful lot of water coming in thru the service conduit. That needs to be addressed.
The breaker stabs in the bottom right corner look pretty burned.
Not overly thrilled with the small neutral either.

Speaking of neutral...... there is a problem with the screw in the left side. That has arced.
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Old 02-24-19, 08:49 AM
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The screw pointed to by the pink panel may have been loose, causing the arcing even with very small current flows.

Turn off the main breaker. Get a flashlight if needed. Undo that screw and clean it and the lug including the underside of the lug where it contacts the bus bar which also needs cleaning down to bare shiny metal. Then screw it all back together. Tight but not stupendously tight.

If the mating surfaces have become roughed up due to the arcing including tiny blobs of melted metal left behind, it is possible that those parts need to be replaced. That could get expensive.

Some inspectors will consider it adequate ground and neutral bonding if both of the bars have (preferably green) screws digging into the panel back. If there are neutrals on each bar it is recommended that a jumper wire be run between holes in each bar as suggested by the small red circled locations in the OP's picture.
 
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Old 02-24-19, 09:43 AM
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There is no need to jumper the neutral bars together. That is already done with a factory installed bar that runs behind the main breaker.
 
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Old 02-24-19, 11:07 AM
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I didn't think I needed to enlarge the circled areas too. There is no additional jumper required between bars. I would recommend two panel bonding screws. One in each side.

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