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  1. #1
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    Default Sub-panel wiring

    Looking for commentary about the wiring in this sub-panel. It is connected via a 100amp breaker at the main but without a neutral wire. The panel is marked 240v and i've read that these don't need a neutral but my knowledge does not go that far. There is only one bus bar that is bonded to the panel that has the grounds attached to it. My understanding is that subs need 4 wires and the neutrals must be connected to their own bus that is isolated from the panel. Thanks.

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  2. #2
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    Default Re: Sub-panel wiring

    All the loads are 240 volts and do not need a neutral.

    The grounding conductors are properly bonded to the enclosure.

    All answers based on unamended National Electrical codes.

  3. #3
    Mark S. Connely's Avatar
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    Default Re: Sub-panel wiring

    We need more information. We need to know the load what it is IE if it is a dryer or an electric stove than a nuetral is needed, also if any load has a transformer that connects to g/n than you will need a ground and neutral.
    if however it feeds 240 v strip heaters that are 240 only then the panel can be marked plainly "240 v loads only" and it can be used as it is


  4. #4
    Roger Frazee's Avatar
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    Default Re: Sub-panel wiring

    Quote Originally Posted by Mark S. Connely View Post
    We need more information. We need to know the load what it is IE if it is a dryer or an electric stove than a nuetral is needed, also if any load has a transformer that connects to g/n than you will need a ground and neutral.
    if however it feeds 240 v strip heaters that are 240 only then the panel can be marked plainly "240 v loads only" and it can be used as it is
    I am guessing that as the panel shows good workmanship an experienced person wired it. Jim is likely going to be correct but I do agree that more information is required to be 100% certain that the panel is for 240 volt loads only. Looks like it but "looks" can be deceiving.


  5. #5
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    Default Re: Sub-panel wiring

    There is no way you could get 120 volts out of that panel unless you a) connect one of the black feeder conductors to neutral in the main panel or b) use a transformer to reduce the 240 volt output to 120 volts, which is not likely to be the case.

    That type of setup is not uncommon here for electric baseboard heaters, all running nicely on 240 volts.

    Below are pics of a heating only panel. The white conductor from that feeder cable was clipped off. This panel is metered separately and the homeowner gets to pay a reduced rate for heating only.

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    Last edited by John Kogel; 07-10-2011 at 02:27 PM. Reason: Or c) see JP's post below
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  6. #6
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    Default Re: Sub-panel wiring

    Quote Originally Posted by John Kogel View Post
    There is no way you could get 120 volts out of that panel unless you a) connect one of the black feeder conductors to neutral in the main panel or b) use a transformer to reduce the 240 volt output to 120 volts, which is not likely to be the case.
    Incorrect.

    You could install a single pole breaker, connect one conductor to the breaker, connect the other conductor to the grounds, and you WILL have 120 volts.

    While that is NOT a proper wiring installation as it is using the grounding conductor as the grounded conductor and that is not allowed ... it IS POSSIBLE to get 120 volts out of that panel.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
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  7. #7
    Roger Frazee's Avatar
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    Default Re: Sub-panel wiring

    Quote Originally Posted by Jerry Peck View Post
    Incorrect.

    You could install a single pole breaker, connect one conductor to the breaker, connect the other conductor to the grounds, and you WILL have 120 volts.

    While that is NOT a proper wiring installation as it is using the grounding conductor as the grounded conductor and that is not allowed ... it IS POSSIBLE to get 120 volts out of that panel.
    That was exactly my point ....


  8. #8
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    Default Re: Sub-panel wiring

    Quote Originally Posted by Mark S. Connely View Post
    We need more information. We need to know the load what it is IE if it is a dryer or an electric stove than a nuetral is needed, also if any load has a transformer that connects to g/n than you will need a ground and neutral.
    if however it feeds 240 v strip heaters that are 240 only then the panel can be marked plainly "240 v loads only" and it can be used as it is
    Thanks for the inputs.

    The panel serviced the furnace, heat pump, and water heater. All 240V and the panel cover was marked clearly as such (sorry no photo).

    John, are isolated heating panels common up there? Are heating-only subsidies available to all? Just curious...


  9. #9
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    Default Re: Sub-panel wiring

    Quote Originally Posted by Luc V. L. View Post
    Thanks for the inputs.

    The panel serviced the furnace, heat pump, and water heater. All 240V and the panel cover was marked clearly as such (sorry no photo).

    John, are isolated heating panels common up there? Are heating-only subsidies available to all? Just curious...
    The 'Electric Plus' program is no longer available, it was too good to be true, but at the time, there was a push to get people off oil and onto electric. People who signed on in the early 90's are still getting a slightly reduced rate for heating. The program can be transferred to a new owner, but there are hoops to jump through. I see houses where the second meter has been removed, indicating the homeowner did something which allowed BC Hydro to revoke the deal.

    John Kogel, RHI, BC HI Lic #47455
    www.allsafehome.ca

  10. #10
    Paul Johnston's Avatar
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    Default Re: Sub-panel wiring

    Quote Originally Posted by Jerry Peck View Post
    Incorrect.

    You could install a single pole breaker, connect one conductor to the breaker, connect the other conductor to the grounds, and you WILL have 120 volts.

    While that is NOT a proper wiring installation as it is using the grounding conductor as the grounded conductor and that is not allowed ... it IS POSSIBLE to get 120 volts out of that panel.
    What does that mean Jerry? "it is using the grounding conductor as the grounded conductor and that is not allowed." What would you use the grounding conductor for?


  11. #11
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    Default Re: Sub-panel wiring

    Quote Originally Posted by Paul Johnston View Post
    What does that mean Jerry? "it is using the grounding conductor as the grounded conductor and that is not allowed." What would you use the grounding conductor for?
    A "bootleg" neutral if some doofus decided to connect a 120V load from that panel, or one like it.


  12. #12
    Paul Johnston's Avatar
    Paul Johnston Guest

    Default Re: Sub-panel wiring

    Quote Originally Posted by Rollie Meyers View Post
    A "bootleg" neutral if some doofus decided to connect a 120V load from that panel, or one like it.
    So how should the ground be ran? Bare wire?
    Thanks


  13. #13
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    Default Re: Sub-panel wiring

    Quote Originally Posted by Paul Johnston View Post
    So how should the ground be ran? Bare wire?
    Thanks
    Hello Paul in Costa Rica. The groundING conductor can be bare or not. The groundED conductor is the neutral, usually white in color. What JP describes is using that grounding conductor, whether it is bare or not, as a neutral, because neutral is bonded to ground back at the main panel.
    Doing this would energize all the grounded components like the panel enclosure and the j-boxes, which would be reckless, to say the least.

    John Kogel, RHI, BC HI Lic #47455
    www.allsafehome.ca

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