Hi I am new to the forum but it seems to have a lot of good information. I have 40 circuit Siemens panel with 39 slots filled. I want to install a generator interlock for my generator but need the top two slots on the right open for the 30 amp gen breaker. Can I physically put 2 tandem breakers in the 3rd and 4th slots down on the right side so i can free up the top two slots for my 30 amp 240 breaker? The panel would still only feed 39 circuits since the generator breaker is technically an input.

Any advice would be appreciated

 

Welcome to the forums! You can do that. That is if you don't want to install a Genrac type switch setup and inlet for the generator.

 

Thanks for the reply. I would rather manage my own loads in my house than get stuck with 6 or 10 circuits i have to choose. Do i buy the regular Siemens QP tandem type breaker?

 

If that is what your panel calls for, yes. The problem in managing your own loads from the panel is that you will invariably overload the generator or breaker. With the switch and inlet, you are limited. Let us know how it goes with the generator!

 

Can you physically do it, yes. Can you legally do it, no. You have a 40 circuit aluminum bus CTL panel. Installing a tandem breaker would violate the U.L. Listing on that panel. A CTL tandem won't fit your panel anyway. Yes, a non-CTL tandem breaker would physically fit, but you shouldn't do it. Non-CTL breakers are for replacement use ONLY in pre 1968 vintage panels only! What you probably should do is to look for two lightly loaded circuits and combine them as one circuit, thus freeing up the second space you need for backfeeding a 2 pole breaker after you rearrange the circuits to get those two spaces at the top right.