ECN Forum Forums Code Related Discussion NEC & other Code issues Modifying panel to fit main breaker

Yeah that is a problem.

Steve this is something an electrician knows.

Steve....really man....you in over your head, higher an electrician.

Bob

Again, I'm not going to put any breaker in the panel. At this point, the discussion is acadamic...
I agree, something is wrong.

Re: the 200A panel. I wanted space in the panel for 20 circuits. The 200A panel had ample space for all the circuits I wanted to add, but the 125A panels would have had every single slot used (and was unrated for stacked breakers), which is unsat as far as I'm concerned. In addition, the 200A panel was cheaper! As there is no code forbidding an overrated panel, the choice was obvious. I would have preferred to give it a dedicated 200A service, but I only have 200A service to the house, and the main loads are split about evenly between the panels, and NEC requires a 100A service (or would if this was a service and not just a branch circuit). So, I plan for 25% more, and wire it up as a 125A, pull #2 90C conductors, and save some money and effort. Voltage drop difference between #2 and #1 is negligible. (NEC only requires a 200A service to this house, btw, I'm not overloading the main.)

As to the 200A main, the Siemens panel label lists MBK125A, MBK150A and MBK200A as the main breakers. I have not seen MBK125A anywhere for sale, and the photos of the MBK150A and MBK200A online on various vendor sites are described as "4-breaker" and one site even shows a photograph of a breaker identical to the one I'm using. Siemens' website describes the MBK200 as "reversed handle" implying it's intended to be installed upside-down, but then has a photo of a completely different form factor. For $477.

Lowes carries MBK200 for $57. Cheapest I've seen anything else listed was a used MBK150A online for $126. Siemen's website lists them for $477. So, screw that, I bought the MBK200 at lowes- I figured I could always return it. It wasn't until I got it home that I realized it didn't match the cutout.

The OCP for this circuit is a 125A breaker in the feeder panel- this breaker is not protecting a tap conductor, so the 200A main would have simply been a local disconnect switch. So, installing a 200A rated "switch" should be acceptable. That the switch is designed to provide 200A OCP would be irrelavant in this use.

This is not a bus-fed breaker. For starters, why would lowes be selling a bus fed breaker? Also, the instructions on the breaker are to remove the lugs from the panel and install them on the breaker. I haven't torn the sticker off the back (I want to return the breaker) but the instructions indicate there are screw terminals there where the lugs removed from the panel would bolt on, and the breaker would bolt to where the lugs were. Everything about the breaker appears to fit perfectly in this panel except the dead front.

Edit: Photo of the MBK200 installed in a panel on this pdf, showing terminal lugs on top: http://automation.usa.siemens.com/SpecGuide/Sections/Sec19.pdf

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iwire, c'mon! I'd expect you guys to say something like that about making the connection to the existing panel, but for this stuff? I mean, there is definately a level of difficulty and professional knowledge required, but I'm not a laymen! I just haven't been doing this long enough to have memorized the relevant codes like y'all have and constantly have to work to make sure I'm doing it right. At least here I have the luxury of knowing a city inspector will be coming up behind me and making sure I won't burn my house down. No such luxury on my day job, so I'm very concientious not only of code, but also good engineering practice and the myraid "what ifs" which include terrorist attacks and possibly outright bombings by other major powers... Usually I don't have to get into this degree of detail, though, most of the time, I just tell them I want a 150A breaker and let the contractor worry about ordering the right one and the necessary hardware And THEN tell them it's wrong when I come and inspect the site, heh.

[This message has been edited by SteveFehr (edited 07-23-2006).]

Whats with the piece of black wire between the neutral bars?? and why a GE breaker in siemans panel(the 30 amp looks like a GE to me)

Walrus:
The 'black wire' is the factory jumper to connect the two neutral bars in this panel. It can be removed (field) to 'create' one neutral and one ground bar.

As to the GE CB, yes, it's a GE in all it's glory. IT MAY be 'approved'; I'm not sure one way or the other, as I said I'm not a Siemens Resi maven

Steve:
The point I am making is what I said, something is not right. You are aware of it. That's good. You seem to be on the right track.

That said, I did not imply there was anything wrong with the larger panel, circuit capacity, nor buss amperage rating. My only comment was that you should NOT cut the panel cover, but seek the proper materials.

I'm not a lover of shopping at any 'big box' store, again this is a personal opinion. The local suppliers deserve support from EC's
Again, my opinion. I have used big boxes in dire need of something, and have witnessed gross mis-information. That's another thread.

John

Yeah, big box being the big box, they didn't have enough 30A or 20A in stock and I ended up short. I had that GE sitting around- figured I'd ask the inspector about it during the rough-in inspection. I couldn't find the form factor printed on it to verify, but it looks to be compatible with the panel, so I don't see that it would be an issue.

The inspectors here follow the "my code" as opposed to any particular code book, so it's always a crap-shoot...

[This message has been edited by SteveFehr (edited 07-23-2006).]

Steve,
G.E. breaker in Siemens panel.
Read the labeling on the panel cover. It will tell you what breakers are accepable for installation in the panel. NEC 110.3(B) manufacturers instructions applies.
Inspectors are not perfect. We don't / can't catch all the errors that an installer can make. You have to do what is right.
I have seen panels fail when breakers that "fit" failed to make good contact on the bus and burned the back of the panel out. One in as little as six months from time of installation.
Alan--

To be honest, I was thinking the same thing. It fits, but doesn't seem to fit quite right. Not worth the risk of a fire for an $8 breaker.

Since no one else has asked...I will...How's that thumb feeling? (img6147pn9.jpg)

LOL..

I figured the black wire on the neutral bar was a factory piece, which justified my first thought, cheesy

Walrus:
Believe it or not, that's one of the "better" designs for the neutral/ground bar jumper.

UL approved, listed/labeled, etc.

John