making holes in mb or breaker boxes

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wireperson

Senior Member
Location
Florida
is it against the code to make your own holes in panels or MB boxes , and not use the pre made ones from factory?
another question , where in the codes is about light fixture in a clothe closet? distance from wall, or if it must be on wall not ceiling?
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I agree with jumper but might add, if you are bringing in larger conductors you might watch 312.6
 

tryinghard

Senior Member
Location
California
The box may not have factory punched knock outs, you just have to connect correctly. Check out Article 410 for your lighting (echoing jumper).
 

roger

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Staff member
Location
Fl
Occupation
Retired Electrician
is it against the code to make your own holes in panels or MB boxes , and not use the pre made ones from factory?
Sounds as though you only deal with residential load centers. I would say ninety five percent of the panelboard enclosures, gutters, cabinets, etc... I purchase have no factory KO's, so if we were not allowed to make our own KO's we never could wire anything.


It would also make manufacturers of KO punches and hole saws mad.;)


Roger
 

sameguy

Senior Member
Location
New York
Occupation
Master Elec./JW retired
Try out the carbide hole saws, nice.
They have a ring on them that keeps the cutter from entering the "box" more than ~1-1/4" deep depending on size.
 

jim dungar

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Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
I was just wondering if it's not a violation of the UL
The UL label says how the device left the factory.

Technically, as soon as you do anything to it, like cut a hole or even knock out a knockout, you run the risk of "violating" the UL listing, and it becomes the responsibility of the AHJ to accept the installation. UL encourages the AHJ to contact them if there is a question concerning the field installation negatively impacting the listing.
 

raider1

Senior Member
Staff member
Location
Logan, Utah
I was just wondering if it's not a violation of the UL

Keep in mind that the box that the panelboard is installed in is listed as a cabinet, the panelboard is most likely listed separately.

If it is a violation of the listing to make your own holes in a cabinet then with most commercial panelboard cabinets it would be tought to get wires into since quite a few come without any factory knockouts.

I hate cabinets that have factory knockouts for anything other than residential. For commercial work I would much rather make my own holes where I need them.

As for the clothes closet lighting question, if you are uisng the 2008 NEC check out 410.16.

Chris
 

lakee911

Senior Member
Location
Columbus, OH
You can generally order them with or without the knockouts.

Is it a violation to drill across the knockouts as I have done before? What I mean is say drilling a 2.5in hole between rows of 3/4in knockouts.
 

tommy

Senior Member
Location
Maryland
I would say yes to knocking out for bigger holes needed as long as connecter fills the hole completely otherwise you would need to use reducing washers to make a solid connection to the panel can or alot of cans come with concentric on top and solid on bottom or vice versa and I have flip flop the ends to be able to knockout my hole.No code reference though sorry.
 
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