Comments on ground wires (left side)

[jweinberg]

Anyone care to comment about the ground wire connection on the left side of this distribution panel?

[brian winkle]

The only part that doesn't meet code is the screw. It should be a machine screw threaded into a tapped hole, not a cabinet mounting mounting screw. A terminal lug would've been nice, or even a bar. But not required. Also, most inspectors would request the ground wires be twisted before installing the barrel crimps.

[Greg Fretwell]

How is the cabinet bonded? Is this conduit?
I don't see any paint removed under the screw.
The other issue, is it a sheet metal screw?

I don't imagine an inspector would have much trouble talking them into a grounding bus kit but it may be "hold your nose legal. If it was my house I would shove a grounds wire in that pipe and install the $3 bus bar kit.

[rwand1]

Is this a sub-panel? Looks okay to me. If it is the main panel where is the bonding screw?

Raymond Wand
Alton, ON

[Larry D. Kage]

Originally Posted by Greg Fretwell

If it was my house I would shove a grounds wire in that pipe and install the $3 bus bar kit.

Greg, I'm not following this. Can you expand on the pipe part some more?

Appreciate it.

[Bob Badger]

Originally Posted by lkage

Greg, I'm not following this. Can you expand on the pipe part some more?

Appreciate it.

I think Greg is suggesting a grounding wire run in the pipe with the feeder back to the source attached to a grounding bar in this panel would be a more reliable grounding means than the EMT that is apparently being used as the EGC now.

I do not see that as a big deal but at that same time it is hard to argue against the grounding redundancy of EMT and a grounding conductor.

Just to be clear EMT is an NEC approved grounding conductor and can do that job quite well if installed correctly and all joints are made tight.

It is not unusual to find loose couplings in EMT which can greatly effect the ability of the EMT to handle fault current.

[Bob Badger]

I should also point out that now there is an NEC section requiring a grounding terminal bar installed in panels used with non-metallic raceways or cables. 408.20

However I do not know when that section was added to the NEC.

[Larry D. Kage]

Thanks, Bob.

[brian winkle]

I was in such a rush I didn't notice the absence of a grounding conductor. No way to tell from the pic if there is pipe all the way to the main. If there isn't, well then those grounding conductors are bonded to nothing. Of course they could test grounded thru the furnace gas connection etc if one of those circuits is the air handler.

[Bob Badger]

Originally Posted by brian winkle

No way to tell from the pic if there is pipe all the way to the main.

A scary thought if an electrician left the raceway incomplete.


But your right, if it runs concealed we do not really know.

A reasonable test would be simply hot to ground, I would 'lift' the branch circuit grounds first so a ground is not found through an appliance like a furnace and gas line.

Any real load testing of the raceway could be destructive so for the most part we have to assume the installation was inspected before the walls where closed.

[Paul Burrows]

If you are not sure recommend further evaluation by licensed electrician.

[jweinberg]

Originally Posted by rwand1

Is this a sub-panel? Looks okay to me. If it is the main panel where is the bonding screw?

Raymond Wand
Alton, ON

This is a sub panel inside one of the units in a 4plex

[Greg Fretwell]

I don't know about your Shurtest but my Ecos uses a significant amount of current to test the ground integrity. It will bite you if the ground is open and you are touching the EGC. (lots of warnings in the manual) If the EGC is <1 ohm you probably have a fairly good connection on the EGC.

[Paul W. Abernathy]

Hey Guys,

I would guess for the HI's the most important thing in this picture when reporting is the following:

1.) Incorrect method of bonding the EGC to the Enclosure
2.) Call me names if you will....but in that picture it looks like the lockring is not a what we call "self bonding" style that actually digs into the enclosure and removes the coating and makes a proper bonding on that EMT.

Now....as I have said in the past...I am not really a fan of giving comments on pictures that i can't blow up and see very well so these are just comments...take them for what they are worth.

3.)...Again I can't tell but the screw in the middle of the grounded conductor bar may be the bonding screw...again so many different panels and so on I can't tell...but it would be easy to check that and we will assume you did and it is truly floating. A test from bar to inside threads of the cover screw holes would tell you...lol...

4.) again..just me or I can't tell if the old cloth cables are coming in via a connector....man I am just getting OLD i guess and can't see clearly plus I have the FLU so that always sucks.

Anyway...suggestion is 1.) you are safe to say consult a licensed electrical contractor 2.) improper EGC bonding method and you should cover youself as you atleast suggested a licensed electrical contractor review this panel and they will do the checks on the system to determine if it is properly bonded and grounded from point A to point B.

[Bob Badger]

Originally Posted by pabernathy

Hey Guys,

2.) Call me names if you will....but in that picture it looks like the lockring is not a what we call "self bonding" style that actually digs into the enclosure and removes the coating and makes a proper bonding on that EMT.

Paul I would never call you names but I will point out that all EMT connectors are listed for grounding and the locknuts are designed to cut the paint.

Bonding bushings or locknuts are only required for certain areas, service raceways and for some applications above 250 to ground. I do not believe that this is either.