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Thread: Electrical Code question

  1. #1
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    Electrical Code question

    Hi All, I've been using my new shop for 10 - 12 years and enjoying problem free activity. My electric installation is, I believe, completely safe. I also believe It does not conform to code. One day I will leave this place and someone will likely be tasked to make my installation code compliant. That effort may even require ripping out the whole installation. So, I'm looking for the least destructive solutions to making the shop code compliant, if it can be made compliant.

    Here's what I have. I have 9 outlet boxes, all in parallel, all wired the same. Each of the 9 boxes contains a 220 volt NEMA L8-30 outlet connected to a single 30A circuit breaker. Each box contains a 20A 220 volt outlet and a 15A duplex 110 volt outlet connected to a single 20A circuit breaker.

    The outlets look like the picture. What would you do to make this code compliant? And, what code violations might be identified here?

    Thanks,
    Attached Images Attached Images

  2. #2
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    Bill

    The big question is, was it ever inspected and signed off by the building inspector?? If it's never been inspected and signed off, then it will more than likely have to meet the code in effect in your area.

    Questions like this are difficult to answer via a forum. You will get all kinds of good advice, and some bad too. In the end though, only a license in your area can truly answer the question. Even then there will be some differences of opinion.
    "The first thing you need to know, will likely be the last thing you learn." (Unknown)

  3. #3
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    Quote Originally Posted by Mike Cutler View Post
    Bill

    The big question is, was it ever inspected and signed off by the building inspector??

    If it had been inspected, I wouldn't have the dilemma...

  4. #4
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    Other than not having been inspected, why do you think it doesn't meet code?

  5. #5
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    as long as your wire sizes / breakers are properly sized, and box is not over fill, you should be fine. as they are in parallel i don't imagine you have a bunch of extra connections in the box, so that should be ok. grounds all bonded correctly? only the main panel should have the Neutral bonded to ground. double check the total capacity of your panel as well. Those are the common things I fix in the houses we have had, some of them had to be fixed even after an inspection!

  6. #6
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    Quote Originally Posted by Bill Webber View Post
    ...

    Here's what I have. I have 9 outlet boxes, all in parallel, all wired the same. Each of the 9 boxes contains a 220 volt NEMA L8-30 outlet connected to a single 30A circuit breaker. Each box contains a 20A 220 volt outlet and a 15A duplex 110 volt outlet connected to a single 20A circuit breaker.

    The outlets look like the picture. What would you do to make this code compliant? And, what code violations might be identified here?

    Thanks,
    I don't think that the 30A 220V circuit in the same box as the other stuff is the issue. But, if I am correctly interpreting your post, you appear to be using a single 20A breaker (presumably a 220 volt breaker) that supplies both the 120 volt 15 A duplex receptacles as well as the 20A 220V receptacles. This is called multi-wire branch circuit wiring. Surprisingly, I think that it is allowed. But, there is the potential issue of a 20 A breaker feeding a 15 A receptacle, especially if you didn't pig tail the neutrals and hots and run single lines to the 120 v receptacles. (I am assuming that the wiring for the MWBC is all 12 gauge....) If you used both screw terminals on the duplex rec. and "daisy chained" the 120 v. connections that would be an issue. But it is fixable.

  7. #7
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    Hey Brice, IIRC all the wires to the outlets are pig tailed. My concern has always been putting 220 volt outlets in parallel, especially those that are 30A. Usually 220 outlets are designated for specific appliances and are generally wired to a single dedicated breaker. I've always assumed my big machines would have been required to be wired to individual 30A breakers rather than having three big machines plugged in and running off one breaker. In this situation, if I tried to run the three machines at the same time it would trip the 30A breaker. The same situation exists on a string of 15A 110 volt duplex outlets. My concerns have always been in two areas: 1) stringing high power outlets in parallel and 2) having two different breaker services in the same outlet box. Nice to hear this whole thing may be OK. If push comes to shove I could likely find an inspector to take a look if it sounds like it could be OK.

  8. #8
    I don't believe the NEC limits the number of receptacles on a circuit. If you are using 10 gauge wire on a 30 amp breaker that is all you would need to be code compliant. That's assuming all the outlets are wired correctly.

  9. #9
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    Bill,
    BTW, for your 120 volt circuits, hopefully you wired them so about half use one phase and the other half use the other phase - - that is, kind of balancing the load. One of the benefits of this is with the shared return, the currents cancel each other to some extent if there is current flowing in both phases.

    And yes, I think that Edward is correct regarding no NEC limits on # of recept. per circuit. When I googled it, that is what I found on the internet (which isn't always 100% correct).

    My own personal bias is to keep the 220 volt lines and receptacles separate from the 120 volt lines and receptacles. But that is just a personal thing.
    Last edited by Brice Rogers; 11-05-2019 at 7:18 PM.

  10. #10
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    15 A 120V outlets are permitted on a 20 A breaker, either directly or as a pass-through. It needs to be all 12 ga wire. I don't see anything wrong with what you have done (I'm not a pro!), MWBC's are a common and often preferred wiring method. (as long as all the wire gauges, box fills, and grounding requirements are met.

  11. #11
    The feed into your house is a MWBC. I use MWBC in my shop, with one side of 220 passing thru a sensor that controls DC. This way half the 120 recpt. are connected to DC control.When my shop was built, only the recpts on wall closest to door had to be GFCI controlled. If you need to get around the GFCI requirements, simply use twist lock plugs. This way they aren't general purpose outlets, but dedicated outlets. I'm not sure about having both 30 and 20 amp circuits in same box is kosher.

  12. #12
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    "BTW, for your 120 volt circuits, hopefully you wired them so about half use one phase and the other half use the other phase" Yes, I did that.

    "And yes, I think that Edward is correct regarding no NEC limits on # of recept. per circuit." That's encouraging.

    "My own personal bias is to keep the 220 volt lines and receptacles separate from the 120 volt lines and receptacles." Me too. I would think that would be a code restriction. Loose wires in there could put 220 where you might not want it.

    Similarly, regarding both 20A and 30A circuits in the same box, a loose wire could put a 20A line on a 30A breaker.

    Anyway, thanks for all the comments. I was aware of these risks when I installed the system and I was VERY careful to make sure connections were properly secured. If I find a contractor I'll ask the question. But, regardless, I wouldn't change anything anyway. My reason for asking the question was to make an assessment of the problems my heirs might have and be able to explain the situation prior to my demise. These outlets are in one room of a four-room finished basement. A new owner would likely not be interested in the 30 amp outlets high on the wall and would probably remodel anyway. I think I'll just try to find something else to worry about..

    Thanks for all the comments.

  13. #13
    Quote Originally Posted by Bruce Wrenn View Post
    The feed into your house is a MWBC. I use MWBC in my shop, with one side of 220 passing thru a sensor that controls DC. This way half the 120 recpt. are connected to DC control.When my shop was built, only the recpts on wall closest to door had to be GFCI controlled. If you need to get around the GFCI requirements, simply use twist lock plugs. This way they aren't general purpose outlets, but dedicated outlets. I'm not sure about having both 30 and 20 amp circuits in same box is kosher.
    You don't get to use the "dedicated outlet" anymore it went away many NEC editions ago, all 120V receptacles in a shop, garage, outbuilding require GFCI protection with no exceptions & that includes receptacles installed in the ceiling for lights, openers, & so on.

  14. #14
    BTW you cannot have 220 and 120 volts, it is possible to have 220Y/127 volts if the transformer taps are set for it, and other things are in place.

  15. #15
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    No such a thing as 110/220V in US or Canada. There's 120/240V single phase, which is what most detached residential is, or 120/208V, which is derived from a 3 phase service, common in commercial & industrial buildings.

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