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I have a detached garage that has a 3 wire feed, powered from a separate 100amp disconnect from the main panel. Originally the old box had the ground and neutrals together on the same bar. I discovered this upon installing a new box and assumed it was wired wrong due to everything I've read about sub panels and how they shouldn't be bonded.

Upon further research I have seen others say that since my sub panel isn't connected to my main panel in the house, that my sub should have ground and neutral bonded. I'm without power for 3 days now.

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    You have a breaker for your garage and house at the meter correct? What year was this installed? If prior to 99 back then code allowed 3 wire and the ground and neutral were bonded. BUT After 99 this was no longer code compliant if my memory serves.
    – Ed Beal
    Commented May 10, 2019 at 18:58
  • I have a breaker next to the meter for my garage, but not the house. The only one for the house is the one inside the main box. I'm not sure when it was installed. I've only lived here 6 years. The box was an old push matic I believe it's called. So if i bond the neutral and ground, should I have a grounding rod into the ground outside? I'm a newbie when it comes to this stuff and really dont have the funds to hire anybody. I truly appreciate your reply
    – Bradminicus1989
    Commented May 10, 2019 at 19:38
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    Post pictures of all the components preferably with the covers removed
    – Kris
    Commented May 10, 2019 at 23:51
  • Thanks guys, i got it figured out. I appreciate your time
    – Bradminicus1989
    Commented May 11, 2019 at 0:44
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    Where are the neutral and ground bonded now? Be aware that having restored power in home and garage is not a guarantee that everything is safe and done according to code.
    – Kris
    Commented May 11, 2019 at 2:00

2 Answers 2

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Since it's a subpanel, neutral and ground should be put on separate bars. That's always the case.

If you are certain you have an ungrounded 3-wire feed, then you can jumper neutral and ground at the panel. However you should be prepared to easily remove that jumper.

Not all grounds are wires. Metal conduit is a grounding path.

As soon as feasible, run a ground wire. It doesn't need to be in the same cable or route as the feed. If it's conduit, it can be fished with some difficulty. It also doesn't need to enter the house, if the house has a ground rod, it can go there instead. As soon as you have retrofitted, remove the neutral-ground jumper.

Remember the detached outbuilding also needs its own ground rod.

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  • Does the ground rod have to be in if, you went to 4wire system? Can see that in a 3wire ,two hots and a neutral, and add a ground rod.
    – user101687
    Commented Jun 14, 2019 at 21:13
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Pushmatic breakers haven’t been around since the early 70’s so your 3 wire feed and neutral/ground being together was legal back then, if legal at the time of install it is still legal today, with that said current code would not allow it but there are hundreds of thousands of subs wired this way.

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  • That said, Will he need to add ground rods,if none present?
    – user101687
    Commented Jun 14, 2019 at 21:05

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