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Thread: Subpanel

  1. #1
    DIY Member rayh78's Avatar
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    Default Subpanel

    Been in this house 20 years. Have a subpanel in the garage I never paid much attention to.
    Have 4 of 20 amp breakers. Two for garage, one for aircompressor and a GFI breaker for pool pump.
    Notice the neutrals and grounds all went to the same bar. So I picked up a ground bar to add to the subpanel to separate neutrals and grounds.
    But then I noticed it is feed by a 50 amp breaker in the main panel box with 6 2 wire. So it has 2 hots and just the ground feeding the one bar for neutrals and grounds.
    Should I do anything? It has been this way for 20 years.
    If I do decide to add a neutral can I just add one wire back to the panel box instead of running a whole new 6-3 wire 70 feet.

    Thanks for any suggestions.

  2. #2
    Retired Defense Industry Engineer jadnashua's Avatar
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    If everything on that subpanel is 240vac, you could live without a neutral, but it would be problematic if any of it is 120vac. The ground is NOT supposed to be carrying normal current, only the hot leads and the neutral. If the feed is a cable, and not wires in say a conduit, I do not think code allows you to run a separate wire as a supply.

    One of the pros will chime in, but if I understand your description, yes, it should be fixed.
    Jim DeBruycker
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    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

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    DIY Senior Member Murphy625's Avatar
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    Neutrals and Grounds should only be mixed at the main panel.

    Ground wires that carry current are called Neutrals and MUST be insulated like a hot wire.

    From your description, your sub-panel should be 240 only! If you have any 120 breakers plugged into it and they are using the earth grounding wire to carry current back to the main panel, you could be asking for trouble. Yes, electrically speaking it will work fine but its a major safety issue and should be fixed.

    I did have a issue similar to yours once. We sunk three grounding rods into the ground far enough so that the tops were 6 inches below the surface. We bonded them all together, rubberized the connections and ran an insulated neutral back to the transformer. We also bonded that to the buildings steel frame and a water pipe. It probably wasn't code, but I deemed it safe enough for the purpose at the time.

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    Electrician ActionDave's Avatar
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    Quote Originally Posted by rayh78 View Post
    Been in this house 20 years. Have a subpanel in the garage I never paid much attention to.
    Have 4 of 20 amp breakers. Two for garage, one for aircompressor and a GFI breaker for pool pump.
    Notice the neutrals and grounds all went to the same bar. So I picked up a ground bar to add to the subpanel to separate neutrals and grounds.
    But then I noticed it is feed by a 50 amp breaker in the main panel box with 6 2 wire. So it has 2 hots and just the ground feeding the one bar for neutrals and grounds.
    Should I do anything? It has been this way for 20 years.
    If I do decide to add a neutral can I just add one wire back to the panel box instead of running a whole new 6-3 wire 70 feet.

    Thanks for any suggestions.
    The devil is in the details but the short answer is prior to NEC 2005 this was allowed.

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    Jack of all trades DonL's Avatar
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    Quote Originally Posted by ActionDave View Post
    The devil is in the details but the short answer is prior to NEC 2005 this was allowed.

    If that is the case and you make any modifications to it, Then it will need to meet today's code.

    It sounds like the wrong wire type is feeding it, Even if code did allow it.

    As mentioned it depends if 120V is being used. If there are neutrals on what it feeds then it is most likely using 120 as well as 240.



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    DIY Member rayh78's Avatar
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    Quote Originally Posted by ActionDave View Post
    The devil is in the details but the short answer is prior to NEC 2005 this was allowed.
    Yes the breakers are for just 120V circuts.

    But do I understand correctly that you are saying that it is not a against code the way it is since this was done before 2005?

    Thanks

  7. #7
    Electrical Contractor/Instructor jwelectric's Avatar
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    Quote Originally Posted by rayh78 View Post
    But then I noticed it is feed by a 50 amp breaker in the main panel box with 6 2 wire. So it has 2 hots and just the ground feeding the one bar for neutrals and grounds.
    .
    You have a very serious problem. The bare wire is now and has always been required to be insulated. This needs attention now and should not wait even one minute before being repaired.


    there needs to be a four conductor cable installed from the 50 amp breaker to the panel that has two insulated (black and red) conductors that land on the busbars of the panel along with one insulated white conductor that is isolated in the panel from the bare conductors.

    have this repaired as soon as possible

  8. #8
    Retired Defense Industry Engineer jadnashua's Avatar
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    120vac circuits REQUIRE a neutral, and while at the main panel, the neutral and the ground are tied together, you CANNOT safely rely on the ground wire (supposed to be there for SAFETY only, not current except in a fault) to provide the return path. Obviously, it has worked, but it is NOT safe.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  9. #9
    DIY Member rayh78's Avatar
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    Quote Originally Posted by jwelectric View Post
    You have a very serious problem. The bare wire is now and has always been required to be insulated. This needs attention now and should not wait even one minute before being repaired.


    there needs to be a four conductor cable installed from the 50 amp breaker to the panel that has two insulated (black and red) conductors that land on the busbars of the panel along with one insulated white conductor that is isolated in the panel from the bare conductors.

    have this repaired as soon as possible
    So not covered under the old code?
    Just thinking here. It will be a pain fishing the wire to the main panel. Rest pretty easy. But any problem if I just ffed the subpanel with a 120 volt 30 amp breaker for now and frre up the neutral wire. Easy to do and at least try to see if I have a load problem and trip breakers.
    thanks

  10. #10
    DIY Senior Member Murphy625's Avatar
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    Quote Originally Posted by rayh78 View Post
    So not covered under the old code?
    Just thinking here. It will be a pain fishing the wire to the main panel. Rest pretty easy. But any problem if I just ffed the subpanel with a 120 volt 30 amp breaker for now and frre up the neutral wire. Easy to do and at least try to see if I have a load problem and trip breakers.
    thanks
    That would not be a problem. To be clear, you would pull the 220 volt breaker at the main panel and replace with a 120 single pole breaker. One of the 220 lines now becomes a 120 volt hot, the other becomes the neutral. Make sure the neutral is white in color. If its any other color, you'll need to go get some white tape and wrap the wire up where it enters into the box and is visible. So now you'll have a hot wire, an insulated neutral, and a bare ground. you're good to go!

    You won't be able to use the 220 volt air compressor however.

  11. #11
    DIY Member rayh78's Avatar
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    Quote Originally Posted by Murphy625 View Post
    That would not be a problem. To be clear, you would pull the 220 volt breaker at the main panel and replace with a 120 single pole breaker. One of the 220 lines now becomes a 120 volt hot, the other becomes the neutral. Make sure the neutral is white in color. If its any other color, you'll need to go get some white tape and wrap the wire up where it enters into the box and is visible. So now you'll have a hot wire, an insulated neutral, and a bare ground. you're good to go!

    You won't be able to use the 220 volt air compressor however.
    Air compressor is only 120v at about 12 amps. Most single breakers I have seen are 30 amp max to put in my main panel. Do they make anything larger for 120 v?

  12. #12
    DIY Member Stuff's Avatar
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    Quote Originally Posted by rayh78 View Post
    But any problem if I just ffed the subpanel with a 120 volt 30 amp breaker for now and frre up the neutral wire. Easy to do and at least try to see if I have a load problem and trip breakers.
    thanks
    Others have done that. Just mark the new neutral with white. Makes it a 120v panel. every other breaker not used. Could use a 60 amp single pole breaker if you can find one. Usually special order.

    Also - if detached garage will need a grounding rod
    Last edited by Terry; 09-19-2013 at 05:08 PM.

  13. #13
    DIY Senior Member Homeownerinburb's Avatar
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    Quote Originally Posted by rayh78 View Post
    Air compressor is only 120v at about 12 amps. Most single breakers I have seen are 30 amp max to put in my main panel. Do they make anything larger for 120 v?
    You can keep the existing 50 amp two pole breaker, but only use one of the poles. Leave the black wire connected to it. Wrap white tape (no longer permitted, but this is not that big a deal) around the red wire at both ends, fit it to the buss bar at the main panel and the neutral buss at the sub. Attach the bare wire to the buss in the main panel and a grounding buss in the sub panel. Ensure that the neutral buss in the subpanel is isolated from the panel.

    You lose for the time being the opportunity to run 240v, but you can easily have four 20 amp breakers in that panel.

  14. #14
    Jack of all trades DonL's Avatar
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    It sounds like the inspector was sleeping on the job, To have passed that sub panel.
    Theory only works perfect in a vacuum.

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