Adding additional conduit to FS Box

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MikeW

Member
Working in a factory and I want to add a ?? RMC to an existing FS Box. The existing box has one ?? hub that has a conduit in it. Can I drill a hole in the existing box and use a Meyers Hub to add my 3/4? conduit? Is there a NEC section I?d be violating? I have seen some other FS boxes with a hole drilled in them but have a gut feeling this is not an accepted practice. What are your thoughts? Thanks.
 

chris kennedy

Senior Member
Location
Miami Fla.
Occupation
60 yr old tool twisting electrician
If you can't make your own openings in boxes and enclosures why would we carry step-bits and KO sets?:)
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Have to disagree with Chris here.
Cast Boxes, unlike "standard metal boxes", are UL listed under BGUZ. The listing states "Cast-Metal boxes suitable for field drilling and tapping of holes for conduit connections and mounting are marked to indicate the locutions and trade sizes........... "
so, although often done, it does not meet the listing unless so marked.
 

chris kennedy

Senior Member
Location
Miami Fla.
Occupation
60 yr old tool twisting electrician
Have to disagree with Chris here.
Cast Boxes, unlike "standard metal boxes", are UL listed under BGUZ. The listing states "Cast-Metal boxes suitable for field drilling and tapping of holes for conduit connections and mounting are marked to indicate the locutions and trade sizes........... "
so, although often done, it does not meet the listing unless so marked.

I will stand corrected until I check the white book reference given. I for one have never added an opening to a FS box as they are tight enough already. I posted without research.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Mike, I guess you need to either replace the box, add one, or fit in a T-condulet.

All of these might mean the use of rigid compression fittings and/or Ericson couplings.
 

MikeW

Member
One more question.

One more question.

Thanks for responses.

Another question: I see FS boxes with a single hole drilled in the back of box for a ??-20 bolt. The ??-20 bolt is used to mount box to a piece of unistrut using a spring nut. Is this an acceptable practice or a violation of code?
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
.................. Is this an acceptable practice or a violation of code?

somethings are both :)
As long as you don't alter the box, I can see no violation. Other than being "secure", I don;'t know of any Code mounting method requirements.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Another question: I see FS boxes with a single hole drilled in the back of box for a ?”-20 bolt. The ?”-20 bolt is used to mount box to a piece of unistrut using a spring nut. Is this an acceptable practice or a violation of code?
I'd say it's okay as long as the bolt is gasketed or sealed to maintain the box's water-tightness.
 
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