I would like to add a gen-tran manual transfer switch to my electric panel but I live in a condo where the main panel is in an external meter room and my only interior panel I assume is a subpanel.

The bond screw in my panel has been removed which tells me that it is in fact a subpanel.

Now, the manual transfer switch has a ground cable but I do not know if it needs to be connected to the neutral bar or if I should connect it to a screw directly on the metal case.

Which is the safe and correct mounting point for that ground cable? Thanks

  • Can you post the models of the transfer switch and panel you're using? And ideally a pic of your current (sub)panel as well, both with and without the cover. – Nate S. Aug 30 '19 at 20:16
  • Hi Nate, I don't have access to those things right now. The transfer switch is one of those off the shelf 20amp and 6 circuits model. The sub panel is really old and I don't see any grounds anywhere, just the hots and the neutral bars. – user105548 Aug 30 '19 at 20:23
  • Is your building wired in conduit? Ground isn't always a wire; conduit is a valid ground path as well, and in an all-conduit job, you may not need a ground bus in the panel. OTOH, if your building is very old, perhaps it was wired without grounds originally. – Nate S. Aug 30 '19 at 20:28
  • I wouldn't know to be perfectly honest. I will try to get photos asap and post back. Thank for your help. – user105548 Aug 30 '19 at 20:44
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    Keenly interested in seeing the (sub) panel model. The expensive, spaghetti wiring transfer switch may not even be necessary; it may be easier, cheaper and safer to fit a generator interlock, which is simplicity itself. – Harper - Reinstate Monica Aug 30 '19 at 21:21

To the ground bar

Grounds go to the ground bar.

Neutrals go to the neutral bar.

Grounds never go to the neutral bar, ever. Not rocket science here. The only reason anyone has ever had any confusion about that is that in main panels, grounds and neutrals are connnected with an equipotential bond, and because of that, Code allows a shortcut of putting all neutrals and grounds on the same bar, effectively making the whole bar the equipotential bond. Irrelevant here, obviously.

In a facility wired entirely in metal conduit, there may be no ground wires anywhere to be seen, and thus, no ground bar. This is normal. In that case you can obtain an accessory ground bar for that panel and attach to that, or attach via a threaded machine screw to the cabinet (never a sheetmetal screw!) provided the screw's thread is -32 or finer. You are likely to find 8-32 or 10-32 threaded holes all over the panel.

  • I'll be moving the green ground wire to the grounding screw circled here imgur.com/y4KmBhe . Thanks – user105548 Sep 2 '19 at 20:37
  • @user105548 if you are simply wrapping a wire around the post, it must be the only thing on the post. If you put a lug on the wire, then you can stack lugs within reason. Also, posts are exempt from the -32 thread rule. – Harper - Reinstate Monica Sep 2 '19 at 21:00
  • Ok got it. Thanks again – user105548 Sep 4 '19 at 0:00

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