Can I drill holes in this panel?

865resi

865resi

Senior Member
Location
Tennessee
Occupation
Electrician
Can I drill holes in a new panel like they did in this panel in 1972. This is an outdoor main breaker panel. It would be easiest just to drill holes and swap for a new panel. 2017 code.
I can't include the photo, but they drilled 10 holes 1/2" in the back of the panel, next to the breakers. Simple question, can a new panel be altered? Thanks
 
Is it installed outdoors in a wet area? If so, isn't putting holes above live parts a problem in a 3R enclosure unless you're using hubs? What goes through those small half inch holes, as that seems too small for a conduit or cable clamp? If these are mounting holes, that may be OK.

So yes, drilling holes or punching new knock outs in a panel is permitted, but you have to watch other rules about where holes cannot be, or holes left open, etc.
 
suemarkp said:
Is it installed outdoors in a wet area? If so, isn't putting holes above live parts a problem in a 3R enclosure unless you're using hubs? What goes through those small half inch holes, as that seems too small for a conduit or cable clamp? If these are mounting holes, that may be OK.

So yes, drilling holes or punching new knock outs in a panel is permitted, but you have to watch other rules about where holes cannot be, or holes left open, etc.
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Yes, outside main breaker panel. Homeruns come through those 1/2" holes using Romex connectors. Panel was installed 1972.
 
If doesn't appear that any water has entered the panel through those KO's. Is the back of the panel sealed to prevent water from entering? Seems no different than a NM cable connector into the back of a surface mounted FS box. Since this is from 1972 why ask?
 
infinity said:
If doesn't appear that any water has entered the panel through those KO's. Is the back of the panel sealed to prevent water from entering? Seems no different than a NM cable connector into the back of a surface mounted FS box. Since this is from 1972 why ask?
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I'm not sure if it has been sealed. Main breaker is shot, panel need s to be replaced.
 
LarryFine said:
Let me guess: the "B" phase (lower) stab and breaker contact have arced and pitted.

Sometimes, the guts can be inverted, and the bad stab avoided with another tandem.
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I was called for blinking lights in the kitchen. When I got there they said was all 3 bedrooms also. That main breaker was hissing when I touched it.
Anyone know if the 2017 would allow those same holes to be drilled? If no, any code references? Thanks
 
865resi said:
I was called for blinking lights in the kitchen. When I got there they said was all 3 bedrooms also. That main breaker was hissing when I touched it.
Anyone know if the 2017 would allow those same holes to be drilled? If no, any code references? Thanks
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On most panels, you can drill new holes anywhere you want. But with 3R panels, you can't drill above live parts.
Does this panel mount on the outside of house and home runs are going through the wall into the panel?
If you could double up some of the holes, and drill below the live parts, it would probably work.

That's an old Murray panel. You might be able to find one, or maybe Siemens, and just swap the guts.
I did that on a couple and only had to drill new holes for the cover screws.
 
I would just punch the new panel with the same holes. Put a heavy bead of caulk on the back on both sides and the top. Once the panel is secured put a bead of caulk around the outside of the panel. You don't want water getting into the panel but you also don't want water getting into the building through the holes the cables pass through.
 
I would contact the inspector in the area and explain the setup. If those cables are coming thru individual holes in the siding then you don't have much choice other than to install a small trough vertically.
 
Buck Parrish said:
It looks so dry inside that 55 year old panel. Their must be a soffit or a roof overhang above it.
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I agree but it really depends on the inspector. We know what the code states but some look at it with appreciation of the situation knowing that it won't be an issue in this situation.

It is still probably best to use a trough.
 
I don't know if weather proof locknuts work with romex connectors. If not maybe sleeve it with a very short piece of 1/2 inch pvc then a connector. Use this lock nut (pictured below) and you'll be fine.

Also when you get the box off you might find the wire long enough to go lower. A 2 inch hole at the bottom left of the panel would be perfect.


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