I have a Murray LC2040L1125 main lug center as my main service panel in my house. Main line directly from meter comes in through two pole backfed 100A main. There are extra spaces in this load center, and it currently only has 19 circuits on it, far less than the 40 that are allowed.

Question: While I was at home depot yesterday, I noticed that there was a 15/15 tandem for $10 and a 15/15 tandem for $18. One was called "CL" ($10) and the other was "NCL" ($18). The person in the electrical department described the difference as the size of the socket that clicks in to the panel. She suggested that I simply buy both and return the one that doesn't fit.

Does anybody have experience with this load center? Can somebody suggest which breaker to buy?

Second question: Should I get the "Main Breaker Kit" (MBK100M: $120) so that I could remove the backfed main and create an actual main for this load center? OR, is this backfed breaker all right? It DOES shut off all electric in the house with one hand motion.

Thanks!

The breakers are rated CTL and NON-CTL, which is related to circuit limiting.

The NON-CTL breakers are for panels manufacturered before 1968.

I suspect you can use the CTL rated breaker, but check the label on the panel.

A Main Breaker kit would be better, but you can use a breaker in the branch circuit slots as a Main, however, you will need to add a retainer kit for any breaker that acts as a Main backfeeding a panel.