Comments on ground wires (left side)

[Paul W. Abernathy]

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.

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.

[Paul W. Abernathy]

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...

[jcundiff]

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?

[Paul W. Abernathy]

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.

[jweinberg]

Originally Posted by jcundiff

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

Yes John, it is a sheet metal 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)

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

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

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.

[Jay Moge]

Originally Posted by 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.

are non-metalic cables approved for any electrical application????

[jcundiff]

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


Okay- so the discussion re: bonding screw is for not. If there is a bonding screw present, it must be removed.

[ddelaney]

If this is a sub-panel, it should have four wire non-the-less. If not, there is no way to carry the equipment ground to the panel, thus no floating ground. Unless, this sub-panel is fed from another building. But that's a whole different animal.

[jtedesco1]

Originally Posted by jcundiff

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


Okay- so the discussion re: bonding screw is for not. If there is a bonding screw present, it must be removed.

I agree. I have some further questions related to the "two per entry cables" into one connector, and the size of the feeder wires.

If the connectors were designed for that use they would be permitted.

I am not calling this a defect, but keep in mind that this is a requirement that is often ignored.

If the wire size is 4 AWG or larger, the present standards require a temperature rated insulated bushing.

Just a couple of points think to keep in mind