I'm thinking about connecting an additional 240v circuit to the panel in my apartment (7 apartments in the building, NYC) but the panel has no main shutoff breaker installed on it. I believe that the main shutoff breaker for the apartment is located in the basement but I would prefer an additional shutoff on the panel itself for the convenience and also for the peace of mind knowing that I won't get zapped if someone comes along and flips the basement switch on me while working on the panel.

I've never installed a main shutoff in a panel before so here's my questions. This panel can in fact have a main shutoff switch installed right? There is a little metal tear-out section on the panel front piece indicating that a main shutoff switch goes there but how would it attach? It must need to interrupt both hot service wires coming in right?

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  • Do you rent or own? Generally speaking you can't do your own electrical work, especially things like panel changes, in a rental Sep 17, 2020 at 22:41
  • 1
    Have you considered simply locking off your main breaker in the basement while you're working upstairs? Sep 18, 2020 at 0:45
  • Probably the best answer actually ^. Not sure how afraid to be of electricity yet so I thought mayyyybe my panel could be safer. Sep 18, 2020 at 0:48
  • @manassehkatz-Moving2Codidact My mom owns the place. Sep 18, 2020 at 0:51

2 Answers 2


You could install a main breaker (what you're calling a main shutoff) but that REALLY shouldn't be done live, by anyone. You'd have to lift your feeders and land them on the new main breaker terminals.

When the disconnect is not where you can keep an eye on it while you're working, like in your building, it should be lockable. If the disconnect has a one-arm-bandit type arm to open it, those can be locked open with a padlock. If it's just a regular breaker, you might be able to find a breaker lock that clamps on the breaker handle and can be locked with a padlock.


Yeah, there really needs to be a way to lockout/tagout the electric service to this panel.

This looks to me like a convertible panel; that's quite common these days. It's almost impossible to buy non-convertibles anymore. You buy an add-on main breaker of whichever size you please. (That's also how you get a 100A 40-space panel).

My guess is, the main lugs un-bolt, and the main breaker bolts up where they were.

Swish the hot wires around a bit to take up some slack (I would swap which terminals they are on, to add more swish) and you should be good2go.

Make sure you torque all your electrical connections with a torque driver.

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