Punching 2" hole into breaker panel

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jeff48356

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Location
Livonia, Michigan
I was wondering if it is legal to punch a 2" hole into the back of a Square-D 200A panel where there isn't one. I would be replacing an old panel with such a hole already in the bottom center, which is already lined up and centered with the outdoor meter base, interior studs, etc. The Square-D panel only has 2" knockouts on the bottom left and right (refer to the picture). I would like to punch another one the same height on center as those two, but directly in the middle horizontally, so I can place the panel in the same location as the old one. Are there any Code restrictions that would prohibit this, since there is no knockout currently there.
 

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jeff48356 said:
Wow! Kinda makes you wonder why the manufacturer only put a rear center knockout at the top and not at the bottom...
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There probably is not enough bending space for the wires at the end opposite the main. Based on the mounting holes, there is no top or bottom to that panel. I would just put the main at the bottom for this application.
 
jeff48356 said:
Ok thanks! I realize most electricians would simply install the panel with the main on the bottom, since there would already be a center knockout where needed. But I prefer to install panels with the main on top, so therefore I would need to use my hole punch kit.
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So you like trying to crowd more into the wiring space that these days gets even more crowded by the AFCI's you must install? Turn the panel over and put the main on the bottom. I wish Square D would make the interior of N3R loadcenters reversible for bottom feed applications - over 90% of what I install outdoors is bottom fed.
 
jeff48356 said:
Wow! Kinda makes you wonder why the manufacturer only put a rear center knockout at the top and not at the bottom...
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That small hole and the two bumps in the area in question is intended to be able to mount an equipment grounding bar there, and if you are entering with a large raceway/cable it is probably the supply for the panel anyway - turn it over and use the center hole on the other end.
 
don_resqcapt19 said:
There probably is not enough bending space for the wires at the end opposite the main. Based on the mounting holes, there is no top or bottom to that panel. I would just put the main at the bottom for this application.
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Bending space for what? There is no terminations to have to try to bend into within close distance. If one did punch a hole there and enter with say 250 aluminum it will be easier to bend then if one used the back, center hole near the main lugs.
 
I have never understood why so may electricians insist the main lugs/breaker need to be on the top. I want the lugs/breaker to be as close to where the wires enter as possible. The last thing I want is for a large set of wires, especially service conductors to be in the wireway with my branch circuits.

Also as Kwired mentioned, with Square D good luck getting any AFCI breakers installed if there are large conductors wrapping around the panel. They barley fit without any wires in the way.
 
curt swartz said:
I have never understood why so may electricians insist the main lugs/breaker need to be on the top. I want the lugs/breaker to be as close to where the wires enter as possible. The last thing I want is for a large set of wires, especially service conductors to be in the wireway with my branch circuits.

Also as Kwired mentioned, with Square D good luck getting any AFCI breakers installed if there are large conductors wrapping around the panel. They barley fit without any wires in the way.
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For the lack of a better word, it's sloppy to have the main, or lugs, at the top, when fed from the bottom.
 
kwired said:
Bending space for what? There is no terminations to have to try to bend into within close distance. If one did punch a hole there and enter with say 250 aluminum it will be easier to bend then if one used the back, center hole near the main lugs.
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It appears that there is more distance between the center of the KO and the breaker terminations, than there is between the center of the KO and the side wall of the panel.
 
curt swartz said:
I have never understood why so may electricians insist the main lugs/breaker need to be on the top. I want the lugs/breaker to be as close to where the wires enter as possible. The last thing I want is for a large set of wires, especially service conductors to be in the wireway with my branch circuits.
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I agree, however there is an exception. Usually more on the commercial side of things, when we have an outdoor panelboard fed from the bottom with expansion couplings. I like the play to account for ground movement and ease of makeup when the breaker or lugs are on top. Just last week we had one bottom fed with two sets of 500's. It was an absolute bear to makeup, and there is very little flexibility should there be some ground movement.
 
curt swartz said:
I have never understood why so may electricians insist the main lugs/breaker need to be on the top.............
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They start their careers doing resi. Many resi panels are fed with an overhead drop. Putting the main at the top becomes habit rather than 'place it closest to the incoming line'.
 
electrofelon said:
I agree, however there is an exception. Usually more on the commercial side of things, when we have an outdoor panelboard fed from the bottom with expansion couplings. I like the play to account for ground movement and ease of makeup when the breaker or lugs are on top. Just last week we had one bottom fed with two sets of 500's. It was an absolute bear to makeup, and there is very little flexibility should there be some ground movement.
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First off, two sets of 500' is always a bear to make up;)

Expansion couplings are supposed to be for thermal expansion of the raceway, if ground is moving you will have problems no matter what.
 
kwired said:
First off, two sets of 500' is always a bear to make up;)

Expansion couplings are supposed to be for thermal expansion of the raceway, if ground is moving you will have problems no matter what.
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Expansion fittings are the most common method used to comply with 300.5(J).
 
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