Cutting the bottom out of a panel

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Rcr29kh1

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I couldn't find in the search area of the forum if this has been discussed so sorry if this has come up before. The contractor is cutting out a large hole in the bottom of several panels on the job to accomodate the entry of conduits. I tried to explain that transformer, switchboards, switchgear is designed to have open bottoms but panels are not designed to have the bottoms cut out. There is no exposed opening you can put your hand up in. The panel is mounted on a trough that has the identical hole cut in it as well. I also tried to cite code sections
110.12 Mechanical Execution of Work
110.12(A) Unused Openings
300.10 Electrical Continuity of Metal Raceways and Enclosures
300.13 Mechanical and Electrical Continuity
But the contractor says they are not violating any code reference
 
I think 110.3(B) is all you need

(B) Installation and Use. Listed or labeled equipment
shall be installed and used in accordance with any instructions
included in the listing or labeling.
Click to expand...
 
Rcr29kh1 said:
I couldn't find in the search area of the forum if this has been discussed so sorry if this has come up before. The contractor is cutting out a large hole in the bottom of several panels on the job to accomodate the entry of conduits. I tried to explain that transformer, switchboards, switchgear is designed to have open bottoms but panels are not designed to have the bottoms cut out. There is no exposed opening you can put your hand up in. The panel is mounted on a trough that has the identical hole cut in it as well. I also tried to cite code sections
110.12 Mechanical Execution of Work
given how common this practice is, I don't buy this argument at all.
110.12(A) Unused Openings
How is this an unused opening?
300.10 Electrical Continuity of Metal Raceways and Enclosures
I don't see how this affects the electrical continuity of the enclosure one bit.
300.13 Mechanical and Electrical Continuity
this paragraph refers to conductors, not enclsoures
But the contractor says they are not violating any code reference
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Common practice. I see no problem with it. There is no prohibition on cutting holes in listed boxes as long as they are closed up properly afterward. For a type 1 box, being against the trough would appear to be adequate.
 
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You do roughly the same thing if you take a Gutter Panel Connector out of the side of a panel.

JAP>
 
iwire said:
I was thinking pretty much the same thing as I have used wireway flanges a number of times with panels and transformers.
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Ditto, those flanges make for a nice clean install as long as the guy cutting the hole is decent. :)
 
Speaking of wireway. I was looking in the Hoffman catalog at their Type 1 lay in wire way. They have a neat adjustable fitting that proudly proclaims no cutting or welding required. In small print it mentions it is not UL listed.
 
petersonra said:
Speaking of wireway. I was looking in the Hoffman catalog at their Type 1 lay in wire way. They have a neat adjustable fitting that proudly proclaims no cutting or welding required. In small print it mentions it is not UL listed.
Click to expand...

For what it's worth I do not believe the NEC requires listing on type 1 metal enclosures. Of course some areas and job specs do.
 
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