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Evening all. I’ve got an old-late 70s era fuse panel that has a failing main breaker. I’ve tried to cross reference the numbers on the breaker and the best I can come up with is Murray type md breaker, but the “issue LC-880” is throwing me for a loop. Can’t find that reference in any of the charts I’ve found online for Siemens equivalents. The breaker has a sticker that reads “style md, 2 pole issue lc-880. Interrupting rating: 10,000 amp, 120/240vac cu/al a-h murray mount on vertical surface only”

breaker in panel

breaker tag

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    Can you post photos of the breaker in question please? There's a bit of a subtlety with the Murray/Siemens double-frame breakers that can trip one up without careful attention Jan 4, 2023 at 4:14
  • Please take the tour so you can learn about how we work here. You've posted the pics (very helpful) in the box labeled "Your answer". They're not answers, so they go in the question. Simply edit the question and paste the pics in there. No need for the random key presses, either.
    – FreeMan
    Jan 4, 2023 at 16:56
  • Not a solution, just an observation: Often, many houses in the same town were wired using the same equipment. A local supplier may have a stock of "old new" replacement parts that are otherwise hard to find. (An electrician finally found a breaker we needed at the local hardware store after his usual wholesalers were unable to provide it. Since then I've replaced that panel entirely; realistically, it was reaching end of useful life.
    – keshlam
    Jan 4, 2023 at 17:47

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The correct replacement is a QN2200H...

The correct replacement breaker for your Murray MD is a Siemens QN "double frame"; for a 200A breaker, this would be a QN2200H.

...but you'll probably need to have your PoCo "pull the meter" to do the replacement

That said, from the looks of things, said Murray MD appears to be mounted in a multiple-main-disconnect Class 320 meter main, which means that you (or your electrician if you're hiring one to do this work) need to call the power company and have them disconnect your power for the duration of the swap. Fortunately, with the rise of smart meters, most utilities can and will do it for free if you call during business hours, as they no longer have to roll a truck out to your house to physically yank the meter out of its socket, but can tell the meter to disconnect its internal cutoff switch instead.

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