Comments on ground wires (left side)

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

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.

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.

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

Raymond Wand
Alton, ON

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

Appreciate it.:wink:

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.:slight_smile:

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.

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.

Thanks, Bob.

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.

:shock: :shock:

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.

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

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

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.

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.

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.

Bob, I am not debating that and did not post a NEC reference to that. I wanted to explain that while the NEC does accept the method it still needs to be done correctly.

In my view of the picture the top conduit connector lock ring looks like it is not touching or barely touching the enclosure and would not be a reliable bond…again my opinion.

I am aware of the NEC allowance " Tasmanian Devil "…teehee…I was just pointing our physical things the HI needs to look for.

I have seen a EMT into a connector into a panel that has a lock ring on it that is not tight and makes no CUT contact into the surface and thus no effective bond to the EMT and items down stream that use that EMT as their grounding needs.

Opps…forgot to add Bob…Art 250.96 states the concerns about the lockrings…their are two different type of rings on the market and not one is not biting and one is…the concern here is if the EMT is the main provider of the EGC beyond the bonding point…if it is not done correctly it will not be an effective bond…even a standard lockring is not a good bond if not installed correctly…The ones I saw in the picture just seemed very loose but again thats me being over protective…lol

How many times have you seen someone try to make a connection to the enclosure without giving any concerns to 250.96…see it all the time.

Ah…the fact is the locknut SHOULD be listed as such that will dig in and remove the enamal or coating to make a proper connection otherwise art 250.12 also comes into effect…

Heres the way I see it- without refering to the NEC:

  1. The screw looks like a typical sheet metal screw. As stated in the earlier posts, a grounding screw must be a machine screw.

  2. If the panel is a main, then it violates the “six turns of the hand” rule, the grounds and neutrals should be combined and where’s the grounding electrode conductor? (possibly outside of the box)

  3. If the panel is a sub, is it “effectively bonded” through pipe- all the way back to the main. Again, what we cant see in the photo is the possibility of a bonding wire or GEC mounted on the exterior of the panel.

  4. The branch circuit grounding conductors being pigtailed is okay as long as they are all for circuits of EQUAL AMPACITY. I cant really tell in the photo. Looks like the one two-pole circuit has no ground wire - again, probably using the pipe.

Not sure If I’d be able to back it up with the NEC, but as a municipal inspector, I would never accept a hook and screw connection for grounds inside of a load center. I’d still accept the pigtail, but I’d want to see the bonding to the panel achieved with a listed tap or lug.

Just to verify- I assume the feed is to the lugs and entering the bottom of the panel. Is that right?

The reference to the NEC is not really relevant to my post on the lockring…it is to the safety aspect of the installation really. As I just can’t tell in the picture but the lockring on the top just does not look like it is tight against the top of the panel…again could just be my screen and the image.

Anyway…just an observation and something HI’s need to look for…even the Compliant things can develop issues that wont be seen AFTER the electrician leaves and years later…that is where the HI’s come in.

In that location it would be impossible to have a machined screw as that hole is a mounting hole and has the enamal inside the hole edges as well…but chances are they have been scraped off due to the screw currently being used…But the contact between the copper wire itself is minimal when touching enamal…if any.

HI’s dont need to quote CODE but the NEC is based on the NFPA and the NEC is looked at as the minimal safety guideline…so it is safety first.

Just be aware guys…even if you see a loose locknut in a panel for lets say EMT…personally…I am noting it as that bond could be lost if it is loose or not installed correctly…

just be aware of these things…thats what education is about.

Yes John, it is a sheet metal screw

This is not a main. It is a sub panel located in one of the units of a 4plex. The main is outside by the lateral service entrance

Feed is to the lugs on the left coming up through the bottom of the panel. The large conductors coming through the top are to a 50amp breaker for the electric range.