Need help understanding code 250.110 (5)

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Windclaw

Windclaw

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Brevard County Florida
Hello,
I will just get down to it, I am working a rehab/renovation. of a local high school in brevard county florida, a local inspector was giving us a ceiling inspection, we were cited for 250.110(5) , we attached a new conduit(emt) to and existing 4 square box, that alread had an extention ring in place. In short we were told we had to ground the extention ring, the factory screws holding it in place were not sufficent for the purpose, also cited was the UL listing for this "Steel City" extention ring. Now we have complied with his wishes but, I just need to know if this ruling is correct. I had no problem complying with it, I just need to know for future installs, the right way, by code

Please help

Bob:smile:
 
Sounds like you were given misinformation. IMO the two 8-32 screws mounting the extension to the box are sufficient to ground the extension. Those same screws are permitted to ground a raised cover which in turn can ground a self-grounding receptacle. Also those same two screws are permitted to ground a surface mounted receptacle whose cover is dimpled at the screw location.
 
I agree with Rob, sounds like the inspector doesn't understand the code, is misinformed, or making up his own rules.

Roger
 
If this extension ring is an exposed non-current carrying metal part then it has to be grounded. The question is if this extention ring is fastened to the metal box and should that be sufficient. I would think so. This inspector might be pushing things too far. Maybe he's just testing you? Did you use any non-metallic washers?:)
 
While I too think the inspector is off base, it does bring up an interesting point. Understand that I am being somewhat facetious here, and looking into the literal wording of the code versus the intent.

2008 NEC 250.110 says "Exposed non-current-carrying metal parts of fixed equipment likely to become energized shall be connected to the equipment grounding conductor..."

and then it gives the conditions where this applies which includes probably about 99.86% of anything we ever connect.

Now, if we read this literally, it says it must be connected to the equipment grounding conductor.

So, we go to 250.118 to see just exactly what items are considered to be an EGC.

Extension ring isn't mentioned in 250.118 as an EGC.

Also, an extension ring isn't mentioned in 250.8 as a method of connecting grounding conductors.

So if we are using a homerun of EMT and using the EMT as the EGC, and then we use an extension ring to connect (via another run of EMT) fixed equipment to the homerun, then essentially we are either

(1) using the extension ring as part of the EGC (violation of 250.118)

or

(2) using the extension ring as a splice between two portions of the EGC. (violation of 250.8)

Again, with a literal reading of the code, I don't see that it permits either of the above. Notice that the issue is not with the screws connecting the extension ring to the box. It is with the extension ring itself.

Again, I think my position is ludicrous. Please don't berate me for all of this. I am on YOUR side.

I searched various other places to see if there is an "out" for the logic above, because I don't like it. Here is my thought:

250.8(A)(8) says "Other listed equipment" -- if the ring is listed as a connection between EGCs, then there you go. If it isn't listed as an EGC connection, then it is a violation of 250.8.

I also looked at 250.102, 250.96, 250.136, and 250.148 and while there is some room for an argument against my literal interpretation, there really isn't. None of those sections say that an extension ring can be used as an EGC or as a splicing device. Sure, they say that boxes and fittings must be grounded or connected to the EGC, but that does not make the boxes and fittings into an EGC or an approved splicing device.

WAIT A SECOND!!!!

358.2 "...An unthreaded thinwall raceway of circular cross section designed for the physical protection and routing of conductors and cables and for use as an equipment grounding conductor when installed utilizing appropriate fittings.

There it is. But "appropriate" fittings is going to be determined by the AHJ? As in the Art 100 definition of "approved"? So the AHJ could certainly allow the extension ring? But what if he doesn't?

What exactly is the listing on the extension ring? Listed as a splice for the EGC? Listed as an EGC? Listed an as appropriate fitting for utilization with EMT?

Looks to me like this is totally up to the inspector.

UGH.... this post has probably been a complete waste of internet bandwidth.:cool:
 
Gary, it is a good thing that you are an Electrician and not a lawyer, you might argue yourself out of every position!
 
>>>>>>>Gary, it is a good thing that you are an Electrician and not a lawyer, you might argue yourself out of every position!<<<<<<<<


I appreciate that!:grin:

I have always liked thinking about the code in this manner... because even when I am totally confused or totally off base, or even off the planet, I am still learning something, and it helps me remember the code sections.

It sure is alot more fun than just sitting around studying the code.
 
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crazy!

crazy!

Isn't crazy and upsetting at the same time that while here we are trying to understand and apply the NEC to the "T", not only we have inspectors that don't understand the code, but they are to "good to reconsider or learn it the right way' I know i'm sorry i'm grapping about something i can't change.
 
crossman gary said:
So, we go to 250.118 to see just exactly what items are considered to be an EGC.

Extension ring isn't mentioned in 250.118 as an EGC.

Also, an extension ring isn't mentioned in 250.8 as a method of connecting grounding conductors.
Click to expand...
I don't see boxes themselves mentioned in either article, either.
 
infinity said:
This is an example when some common sense should be used by the inspector. :smile:
Click to expand...

The real issue is if you do not POLITELY point out the errors of his ways, he will continually make electricians do something that is not necessary. While this may seem minor it can be costly and in my opinion unnecessary.
 
LarryFine said:
I don't see boxes themselves mentioned in either article, either.
Click to expand...

You are correct.

It all goes back to the EMT article and what is considered as "appropriate" fittings. To me, that means the AHJ has to make the decision.

And a reasonable decision is that the boxes and extension rings are appropriate fittings.
 
Thank you everyone you guys are great!

Thank you everyone you guys are great!

Thank you everyone for answering this post All of them have been printed and given to my "boss" and by the way "crossman" after reading yours I think I last saw him , sitting in the corner contemplating the color of his naval fuzz, but all jokes aside you guys are great confirmed everything I found here. Thank you again
Bob:smile:
 
You're welcome.

One last comment on the inspector saying that the screws from the box to the extension ring were an issue.

250.102 allows screws to be used as bonding jumpers, and of course, 250.8(A)(5).

So I think he is wrong on that part. The screws are acceptable IMO.
 
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