Bare Ground in Conduit?

Status
Not open for further replies.
George Stolz

George Stolz

Moderator
Staff member
Location
Windsor, CO NEC: 2017
Occupation
Hospital Master Electrician
I've heard and practiced that you can't have a bare conductor in a conduit. I haven't had much success in finding that, aside from a dissimilar metals mention in 110.14 that doesn't seem to fit.

So, can you put a bare ground in EMT? PVC? LFMC? LFNC? NYPD? Just checking to see if you were paying attention there...

And where?
 
Re: Bare Ground in Conduit?

It's allowed in our area as long as we use a ground chock to ground the metal conduit.
 
Re: Bare Ground in Conduit?

All conductors are required to be insulated per section 310.2(A), however the exception states bare conductors are allowed where permitted by other sections of the code, such as 250.119 which states egc can be bare, covered, or insulated.
 
Re: Bare Ground in Conduit?

I think there are some special rules about using bare AL as an EGC. I don't allow AL wire of any type so I avoid this problem all together.
 
Re: Bare Ground in Conduit?

All conductors are required to be insulated per section 310.2(A), however the exception states bare conductors are allowed where permitted by other sections of the code, such as 250.119 which states egc can be bare, covered, or insulated.
Click to expand...
I agree, but if you are using ANY aluminum raceways(elbows or entire runs)DO NOT use bare copper. This is not a code issue, however about 8 years ago as an apprentice, I witnessed a kid get his leg shattered. To make a long story short, the bare copper EGC dug into the AL elbow during the pull, and the forman decided to parallel 2 tuggers together along w/ a cumalong.What a rig that was. The cumalong snapped, shot the kid in the shin. Needless to say we had to pull the wire out and start over, w/ a insulated EGC,LOL.
 
Re: Bare Ground in Conduit?

That can happen with PVC and that is why PVC elbows are not recommended. That said, your story is one of stupidity rather than using the wrong materials. If it isn't moving there must be a reason!

-Hal

[ December 08, 2004, 05:34 PM: Message edited by: hbiss ]
 
Re: Bare Ground in Conduit?

This unfortunate accident was certainly not the result of using bare copper in an aluminum raceway. It was because they used two tuggers and a comealong at the same time and the kid was standing in the wrong place at the wrong time. The job foreman should of known better, and if the pull was that hard, I think some other corrections needed to be made in addition to using insulated conductos only.
 
Re: Bare Ground in Conduit?

Just out of curiosity, how often is a cable pulling calculation performed before a pull, and how often is a break-away link installed to prevent exceeding the maximum calculated tension?
(1) All the time. This accident was a result of not doing it.
(2) Half the time.
(3) Seldom.
(4) What are you talking about? :confused:
 
Re: Bare Ground in Conduit?

I don't run the numbers very often but have done them. You will find that the "sidewall pressure" and not the actual pulling tension is most often the limiting factor. "Sidewall pressure" is the crushing force applied to the conductor insulation where the conductor is pulled around bends.
Don
 
Re: Bare Ground in Conduit?

What the heck are you talking about?

I'm not really kidding! :D How do you do a cable pulling calculation? I've never heard of one!

It'd be nice to throw some numbers in somebody's face when they ask me to pull 3 250's in a 2" PVC pipe with no soap, no rope and a lonely fishtape to keep me company! :D Okay, there were four of us, the rest was so though...
 
Re: Bare Ground in Conduit?

George check out this site it does calculations and has some info.

Go Here

[ December 08, 2004, 07:28 PM: Message edited by: iwire ]
 
Re: Bare Ground in Conduit?

Bob, you have no idea how jealous I am, pulling wire with back hoes, stop it. :cool:
 
Re: Bare Ground in Conduit?

Originally posted by physis:
Bob, you have no idea how jealous I am, pulling wire with back hoes, stop it. :( Most times when equipment like that is used some 'cold beverages' have been provided to the excavating contractor for the use of the equipment and operator. :p
Click to expand...
 
Re: Bare Ground in Conduit?

Most times when equipment like that is used some 'cold beverages' have been provided to the excavating contractor for the use of the equipment and operator.
Click to expand...
I don't know if it's good or bad (probably bad) but that always seems to do the trick. :roll:

How many times have you seen the "beverages" consumed on the job, or during lunch break!!! :mad: :eek:
 
Re: Bare Ground in Conduit?

Originally posted by iwire:
George check out this site it does calculations and has some info.
Click to expand...
That is very cool, thanks Bob.

P.S., "some info?" Some gift for understatement. It'll take me a week to digest that! :D
 
Status
Not open for further replies.
Top