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”
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.