Are you allowed to cut and remove part of the electrical pull box and weld back to make the box smaller?

[zemingduan]

The electrician proposes to cut 9" wide from the center of the electrical pull box and weld back together in order to make the existing pull box 9" smaller in width to accommodate a new fresh air duct in the shaft. Is it legal to do this? I think all equipment shall be UL listed or something. If you modified it like this by yourself, it's not legal to do so.

 

[roger]

I have field modified many boxes. Unless they fall under 314.15 there is no NEC requirement for boxes to be listed. I have also had metal fabricators custom make boxes.

 

[Dennis Alwon]

The electrician proposes to cut 9" wide from the center of the electrical pull box and weld back together in order to make the existing pull box 9" smaller in width to accommodate a new fresh air duct in the shaft. Is it legal to do this? I think all equipment shall be UL listed or something. If you modified it like this by yourself, it's not legal to do so.

It depends on the configuration and pipe sizes that are existing in the box. If he shortens it then there may be a compliancy issue.

 

[texie]

I have field modified many boxes. Unless they fall under 314.15 there is no NEC requirement for boxes to be listed. I have also had metal fabricators custom make boxes.

I agree. Back in the day it was routine to fabricate wireways and large J boxes. As Dennis mentioned, the OP just needs to be sure the box dimensions still meet Art. 314 dimensions.

 

[don_resqcapt19]

Make sure that the distance between any wall and the termination point is in compliance with 312.6.

 

[chris kennedy]

Unless they fall under 314.15 there is no NEC requirement for boxes to be listed.

And 376.10 for wireways.

 

[infinity]

Boxes are field modified all of the time and as mentioned often boxes are custom made. I don't see an issue with it. Similarly metal wireways are cut and modified all of the time because they typically come in fixed lengths.

 

[kwired]

Boxes are field modified all of the time and as mentioned often boxes are custom made. I don't see an issue with it. Similarly metal wireways are cut and modified all of the time because they typically come in fixed lengths.

Yes, usually in 12 inch increments. If running to a corner then turning around the corner you about need to modify part of it to make it fit in 99%+ of most instances. Same reason you cut 10 foot lengths of raceway to fit a particular location.

 

[zemingduan]

Thank you all! Very helpful and I always learn something new from this forum. Engineer really needs to know more about how the electric is installed and constructed in the real world!

 

[infinity]

Thank you all! Very helpful and I always learn something new from this forum. Engineer really needs to know more about how the electric is installed and constructed in the real world!

You're welcome. It nice to hear several opinions on a subject.

 

[jap]

I'll be the bad guy.

Factory boxes looks good.
Even home made fabricated boxes look good.
Factory boxes that have been cut welded back an repainted has never looked good to me.

JAP>

 

[kwired]

I'll be the bad guy.

Factory boxes looks good.
Even home made fabricated boxes look good.
Factory boxes that have been cut welded back an repainted has never looked good to me.

JAP>

That might depend on how good the person welding is at that task.

If you ever worked in food manufacturing places that utilize sanitary stainless piping systems there is someone there that can make modifications to a stainless box and polish it when all done and you probably will have a hard time telling where he made the changes. Painted or galvanized enclosures do require more finishing techniques though.

 

[jap]

That might depend on how good the person welding is at that task.

If you ever worked in food manufacturing places that utilize sanitary stainless piping systems there is someone there that can make modifications to a stainless box and polish it when all done and you probably will have a hard time telling where he made the changes. Painted or galvanized enclosures do require more finishing techniques though.

That person is usually me.

JAP>