Rigid Conduit 90 Stub Up

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ed downey

ed downey

Senior Member
Location
Missouri
I Have An Installation Where (6) 3 1/2" Conduits {(3) For The Feed & (3) More To Run Out To Loads} Stub Up To The Bottom Of A 1000A 120/208V Distribution Panel. The Conduits Are PVC Schedule 40 With A Rigid 90 To Stub Them Up To The Top Of The Concrete Floor. The Contractor Installed A Custom Made Junction Box At The Floor Level And Then Cut Out The Bottom Of The Can For The Distribution Panel And Set It On Top Of The Box Which Does Not Have A Top Or A Bottom. Therefore The Conduit Does Not Terminate To Anything. Do They Need A Grounding Bushing On The End Of The Conduits Per 300-10.
Thanks For Your Responses,
-Ed
 
Re: Rigid Conduit 90 Stub Up

They won't need bond bushings if your elbows are 18" deep, but they will need male adaptors and plastic bushings on them if they contain 4 AWG or larger conductors. :)
 
Re: Rigid Conduit 90 Stub Up

Ryan, Thanks For The Response. What Section Are The Bushings Called Referenced In.

Found What You Are Speaking Of In 300-4(f)

-Ed

[ May 07, 2004, 04:38 PM: Message edited by: ed downey ]
 
Re: Rigid Conduit 90 Stub Up

Ed,
If the 90s are exposed in the custom box they will need grounding bushings. The metal raceway is required to be bonded. The exception that Ryan is talking about only applies if all of the metal 90 is under 18" of earth or 2" of concrete.
Don
 
Re: Rigid Conduit 90 Stub Up

I have been told by past instructors, "that everything in an electrical instalation must be UL approved that which it is used" In respect to the custom box that would be a violation, any comments
 
Re: Rigid Conduit 90 Stub Up

A few things, Jes. First, UL (or any Nationally Recognized Testing Laboratory) doesn't approve, they list...see the definition of each in article 100.
Second, items that are listed must be installed within the parameters of their listing...see 110.3(B).
Third, boxes are not required to be listed...see article 314.

So, if the box in question is a listed one, even though it is not required to be listed, we probably have a violation of 1103(B). If the box is not listed, and it doesn't have to be, then there is no violation.

Bare in mind; however, that all aspects of the premises wiring system must be approved. See definition of approved and also 110.2. :)

[ May 07, 2004, 07:37 PM: Message edited by: ryan_618 ]
 
Re: Rigid Conduit 90 Stub Up

You know when I got my masters license back in december I thought I was pretty knowledgeable, But compared to you guys I am clueless. Thanks for agreat website it is a big help!
 
Re: Rigid Conduit 90 Stub Up

Jess,
who made the box??? There are companies out there that can make parts you need and they are u/l listed companies there for they could help.

I have uses them many times. Spendy but the AHJ doesnt question it.
 
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