I'm installing a new 125A distribution panel as a branch circuit off the main panel in a residence. I bought a 200A Siemens panel at the big box that had the ground bar and was supposedly configured for this, but the main breaker they carry for this panel (4x breakers wide, oriented so you push down on the yoke to turn off.) doesn't fit! Which is to say, it fits the panel, the bolts line up, plenty of clearance, etc, but the punchout on the cover is in the wrong spot. Searching for it online, the part# only seems to return more of the same. Siemens website lists the part for $477, but even though I've already got several circuits run, I'd replace the panel before I wasted that kind of money.
Is it acceptable by NEC to just take a grinder to the cover and put a cutout where it needs to be? What's the proper way of closing up the "wrong" cutout? It will end up being an L shaped hole on one corner of the new cutout. Thanks!
It's a 200A "Ultimate Load Center", which will be a 125A branch circuit off a 200A main panel. It will be located in the addition, about 40' from the main panel. Is MLO legal? I'd assumed I needed a local disconnect, but that might be a MIL-SPEC requirement specifically for servicible electronic equipment, now that I think about it... If MLO is OK, shoot, I'll just do that! Where in NEC would the relavant code be, I'm having trouble fining it? If MLO isn't legal in this case, I'll call siemens and see what I can do. It looks like the plate is replaceable, so maybe I can just get the right one for not a whole lot of money.
MBK125A is the breaker I wanted, and it's specifically stated on the label on the inside of the door that it's the right breaker. The one I bought at the big box for $50, the only main breaker for these panels they sell (MBK200) does fit on the bus, it just doesn't fit the panel front. Siemens has the exact same breaker listed for $473 in their catalog. I really intend to use it soley as a disconnect, and use a 125A breaker in the main panel as the overcurrent protection
[This message has been edited by SteveFehr (edited 07-19-2006).]
#99106 - 07/20/0607:01 AMRe: Modifying panel to fit main breaker
Ah, found it, was looking in the wrong section- 408.36(A) only requires that it be protected on the supply side. The only requirements I've found in NEC for local disconnects (6-hand movement rule) are for service entrances to buildings. IRC 2003 is completely silent on the matter. I'm just going to wire this up MLO, that makes it nice and easy!
BTW, I can't find anything in article 408 prohibiting cutting a new hole. And this seems to indicate soldering the L-shaped hole shut would be acceptable: NEC 2005 408.7 Unused Openings. Unused openings for circuit breakers and switches shall be closed using identified closures, or other approved means that provide protection substantially equivalent to the wall of the enclosure.
#99107 - 07/20/0609:00 AMRe: Modifying panel to fit main breaker
That's the ticket right there... "identified" It needs to be identified by the manufacturer for that purpose. Next is the "other approved means"; using a hand built plate approved by the manufacturer (not likely), approved by testing lab - UL/ETL ($$$$$$), or approved by the AHJ (possible, but varies by inspector & locale).
#99108 - 07/20/0610:03 AMRe: Modifying panel to fit main breaker
BTW, I can't find anything in article 408 prohibiting cutting a new hole. And this seems to indicate soldering the L-shaped hole shut would be acceptable:
NEC 2005 408.7 Unused Openings. Unused openings for circuit breakers and switches shall be closed using identified closures, or other approved means that provide protection substantially equivalent to the wall of the enclosure
What kind of customers do you work for?
Are you a licensed electrician?
I can not imagine trying to charge money for a cut and soldered up cover on a new installation.
If they wanted it cobbled together they could have done the work themselves.
Alan gave you great advice you should take it.
[This message has been edited by iwire (edited 07-20-2006).]
Bob Badger Construction & Maintenance Electrician Massachusetts