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Thread: 50A circuit question

  1. #1
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    50A circuit question

    hi, i believe i have this figured out but wanted to be sure and wasnt able to find any old posts on it.
    i'm installing a charging station in my garage and it requires a 50A circuit.
    i have space for a 50A breaker as this was for future charging station use but now i need to wire it. it would be about 50' to a NEMA 6-50 outlet so i'm thinking 2 runs of #6 and 1 #8 for ground?
    i dont know if the NEC book is open to the public but i wasnt able to find it online.
    thank you

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    Re: 50A circuit question

    Quote Originally Posted by superwelder View Post
    hi, i believe i have this figured out but wanted to be sure and wasnt able to find any old posts on it.
    i'm installing a charging station in my garage and it requires a 50A circuit.
    i have space for a 50A breaker as this was for future charging station use but now i need to wire it. it would be about 50' to a NEMA 6-50 outlet so i'm thinking 2 runs of #6 and 1 #8 for ground?
    i dont know if the NEC book is open to the public but i wasnt able to find it online.
    thank you
    I do not believe you can access NEC online except paying hundreds in subscription service.

    Check terminals. You are limited to terminal temperature rating, and must derate if more than three conductors in conduit, or bundled or if it runs through a hot area. #8 copper is rated at 75 degree C 50 amps. I'd still use #6. You won't be there to react if it were to get hot. Whether you need a center tap conductor check instructions. Equipment ground conductor is #8 minimum.

    You need GFCI protection & wet location if outdoor.

    Use exact conformation in terminating, these are notorious for overheated terminations.
    An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.

  3. #3
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    Re: 50A circuit question

    If to feed a 6-50 outlet then as you stated your 2 hot #6's are perfect but your ground only needs a #10 and no need for neutral on that outlet. Up to like 50 feet approx.

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    Re: 50A circuit question

    thank you guys. if i can use #10 for ground that would be great, i have a ton of it haha.
    i understand the equipment ground but if this is a plug (not hardwired) is it considered equipment?
    also, i'll find a calculator but i believe 3/4" conduit would code.

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    Re: 50A circuit question

    Quote Originally Posted by superwelder View Post
    thank you guys. if i can use #10 for ground that would be great, i have a ton of it haha.
    i understand the equipment ground but if this is a plug (not hardwired) is it considered equipment?
    also, i'll find a calculator but i believe 3/4" conduit would code.
    If you are talking THHN that'd be fine if no neutral is needed.
    An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.

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    Re: 50A circuit question

    The NEC is apparently available online at: https://www.nfpa.org/codes-and-stand...ds/free-access

    EDIT: removed some incorrect GFCI protection info....Thanks, rexcormack! I wish we just had a strike though edit feature and that the darn site didn't limit the time window for edits.




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    Last edited by LanceR; 04-30-2021 at 08:20 AM.
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    Re: 50A circuit question

    LanceR,
    It says 150 volts or less TO GROUND so a 230 volt circuit would be 115 volts TO GROUND so
    it looks like it would need GFCI if in a wet location.
    WillieB, am I reading that correctly?

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    Re: 50A circuit question

    Quote Originally Posted by rexcormack View Post
    LanceR,
    It says 150 volts or less TO GROUND so a 230 volt circuit would be 115 volts TO GROUND so
    it looks like it would need GFCI if in a wet location.
    WillieB, am I reading that correctly?
    Thanks, Rex. I do believe that you are correct. I just edit my post and since we don't have a strike through feature to do that with I removed the incorrect statement. I'd have much rather have left it with the strike through though so you post made more sense to new-comers to the thread.
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    Re: 50A circuit question

    Quote Originally Posted by rexcormack View Post
    LanceR,
    It says 150 volts or less TO GROUND so a 230 volt circuit would be 115 volts TO GROUND so
    it looks like it would need GFCI if in a wet location.
    WillieB, am I reading that correctly?
    That is how I read it. NEC changes are not necessarily adopted by every locality. Here at least NEC may be adopted after lengthy panel examination of code changes. 2020 code was just now adopted in VT with numerous amendments'

    As I understand Outdoor, in a garage, or pretty much all locations.
    An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.

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    Re: 50A circuit question

    Don’t install a gfci of any sort, it will cause you nothing but problems, it is in a garage, no need to have it, unless you like having a dead battery and enjoy the walk to the circuit box, then by all means put one in.
    The plug on my wifes tesla has a temperature sensor of some sort. I get alerts of high temperature when it is charging for long periods. I have felt it, it feels warm, but not hot. No discernible degradation at the wire connection points. I am likely going to put in the 14-50 that it was originally set up for.
    You would be wise to run a slightly larger conduit, and to add a neutral to your bundle of wires. It won’t cost that much more, but gives you a lot more options in the future.

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    Re: 50A circuit question

    Quote Originally Posted by walker View Post
    Dont install a gfci of any sort, it will cause you nothing but problems, it is in a garage, no need to have it, unless you like having a dead battery and enjoy the walk to the circuit box, then by all means put one in.
    The plug on my wifes tesla has a temperature sensor of some sort. I get alerts of high temperature when it is charging for long periods. I have felt it, it feels warm, but not hot. No discernible degradation at the wire connection points. I am likely going to put in the 14-50 that it was originally set up for.
    You would be wise to run a slightly larger conduit, and to add a neutral to your bundle of wires. It wont cost that much more, but gives you a lot more options in the future.
    EXACTLY what I was thinking about a GFI on a piece of charging equipment. That is something you most likely will regret. Wire it properly and ground it good and let it rip.

    Think about it for a second as we are on a welding forum. Charger is similar to a welder in many ways.

    You wouldn't setup the welder circuits with GFI's. I don't think I would on the charger either.

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    Re: 50A circuit question

    thanks again guys. i do not plan on using GFCI, like you mentioned, its in the garage and i dont feel like resetting it every couple hours.
    yes i was planning on running THHN but is it different if i do NM-B? i was thinking worse case, if i cant run conduit easily ill just grab a 50' roll of romex. also, actual measurement comes out to 47'.

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    Re: 50A circuit question

    Quote Originally Posted by superwelder View Post
    thanks again guys. i do not plan on using GFCI, like you mentioned, its in the garage and i dont feel like resetting it every couple hours.
    yes i was planning on running THHN but is it different if i do NM-B? i was thinking worse case, if i cant run conduit easily ill just grab a 50' roll of romex. also, actual measurement comes out to 47'.
    Same. 6-2 with ground will be 2-# 6 and solid #10 ground. Or as suggested run with 6-3 with ground just in case one day you want a neutral for 120 volt in a subpanel or a new charger that wants one when this model is obsolete.

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    Re: 50A circuit question

    one more question for you guys.
    i'm not planning on doing this but i've always been curious. say you run a wire from the breaker to a junction box then using wire nuts make another run to another box, does this change anything?
    i know ive see this done on 120v 15A circuits but if your running a 40 or 50A+ circuit to a welder/compressor/dryer do you have to derate the wiring?

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    Re: 50A circuit question

    Challenge isn't can you splice, it's how you splice. Normally we try to put high current loads on dedicated circuits. NEC may not define dedicated circuit. To me it means as few connections as possible. There are a dozen electricians on this forum. We won't agree on how to splice. One thing I won't get argument on is a continuous conductor won't have risk inherent in spliced conductor.
    An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.

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    Re: 50A circuit question

    i totally agree on that last statement. just curious. i'm not an electrician but theres GOT to be a situation where a dedicated (continuous) conductor isnt possible. right?

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    Re: 50A circuit question

    Quote Originally Posted by superwelder View Post
    i totally agree on that last statement. just curious. i'm not an electrician but theres GOT to be a situation where a dedicated (continuous) conductor isnt possible. right?
    Yes, when you have to transition from one wire type to another, for instance THWN in conduit underground coming up into the wall and switching to NM cable.
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    Re: 50A circuit question

    Quote Originally Posted by superwelder View Post
    i totally agree on that last statement. just curious. i'm not an electrician but theres GOT to be a situation where a dedicated (continuous) conductor isnt possible. right?
    There are often splices made in larger wires every day for all kinds of reasons.

    It is not a problem to splice when done with something with some substance to it designed for high amperage splices. Polaris taps or on of the many other types of rubber/vinyl clad aluminum taps or a compression sleeve crimped with hy press.

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    Re: 50A circuit question

    I'm a little late to the party - but just a thought. If you are going through the process to put in that circuit it might be well worth your effort to add 1 more 6g wire for neutral and run a 14-50 outlet. Then adapt from 14-50 to 6-50 between the outlet and the charger.

    This way you have both voltages available there for future use.

    That is what I did here. My old tombstone (round top) came with a range cord on it - NMEA 10-50. So when I set up my inital power cable (from a dryer outlet - 14-30) I wired to a box with a 10-50 for the welder and also put a 5-20r and L14-30r on there. The 5-20 has both horizontal and vertical neutrals so you can use either 5-15 or 5-20. That's my tool plug (drill, grinder, what ever).

    However, when I got my inverter welder it came with a 6-50 plug on it. At the same time I decided to upgrade to a dedicated circuit - new cable, wall mounted outlet (not the dryer circuit). I kept the same theory of the 4 conductor cable, just with 14-50's, with the addition of one more interconnect - at the end of a 25ft extension cord. If I was running a welder alone then yea - the extra neutral/4th wire is useless. But I really like having everything right there at the welder so I can run my 120v gear off the same box. That makes life a lot easier than running a separate extension cord.

    Make sure what ever you "install" is to code - outlet box back to the breaker. Yea, in my case splitting off the 120v and 30a plugs isn't code (they should have separate breakers), but for my uses I'm OK with that - and everything past the wall outlet isn't "installed" anyway - extension cord and the break out box.

    See post 154 for the cabling, 153 has the cord upgrade on the round top welder.
    https://weldingweb.com/vbb/threads/7...47#post8812147

    As far as splicing cables - I don't think that will work very well on bigger cables. You may look in to terminal blocks and putting ring terminals on your wires. For 6 gauge wire that will be a beefy terminal strip and require a substantial box. You're probably not going to make that kind of splice in a 2 gang wall box, for example.

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    Re: 50A circuit question

    Split bolts are pretty nice for connections with thick wire (larger than ~10 ga).

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    Re: 50A circuit question

    I've used several of this type splice kit in the past.
    They are well made and work good but they do need some room!

    https://www.morrisproducts.com/pc_pr...9F44E287D7E943

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  33. #23
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    Re: 50A circuit question

    Quote Originally Posted by jwmelvin View Post
    Split bolts are pretty nice for connections with thick wire (larger than ~10 ga).
    Yes they are when doing your own work and time is of no consequence, but with today's labor costs split bolts are becoming more or less obsolete as the insulated Polaris type connectors have moved in, quick, easy, minimum skill required and easily reversible.
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    Re: 50A circuit question

    so today i took a look at the charger and its actually 14-50. i dont know why i was assuming it was 6-50. i will def do a 6/3.
    thank you

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    Re: 50A circuit question

    Quote Originally Posted by bigb View Post
    ... the insulated Polaris type connectors have moved in, quick, easy, minimum skill required and easily reversible.
    Those are neat, thanks. Amazingly expensive it seems, but I hear what youre saying. Im glad to know about them.

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