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Thread: 480V in Residential

  1. #1
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    480V in Residential

    Hi,
    I have a situation where I need to do a long run for a PV system in residential. I was thinking of going with a transformer (and yes I know it will be expensive but way less then other options) from 120 to 480 then bringing it back down to 120 for voltage drop and I need to use an existing pipe that is only 2"



    My question is......Are there any codes that prohibit 480 in a residence (besides the 277V Lighting code)?
    “He has no enemies, but is intensely disliked by his friends.”

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    Quote Originally Posted by Castrovinci View Post



    My question is......Are there any codes that prohibit 480 in a residence (besides the 277V Lighting code)?
    In your situation, No. There are branch ckt limitations in 210.6, but those are irrelevant here.

    IIRC the limit in your case is 600v- see 690.7.

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    What is the distance and the load you will have? The 2” will be limiting.

    600v @ 100 amp @ 600 ft will give a VD of about 22 with 2/0 al wire. That could be a pretty tough pull even without 90s.

    The EG will need to be increased in size.
    Tom
    TBLO

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    Quote Originally Posted by Castrovinci View Post
    Hi,
    I have a situation where I need to do a long run for a PV system in residential. I was thinking of going with a transformer (and yes I know it will be expensive but way less then other options) from 120 to 480 then bringing it back down to 120 for voltage drop and I need to use an existing pipe that is only 2"



    My question is......Are there any codes that prohibit 480 in a residence (besides the 277V Lighting code)?
    Why not just bring the dc strings back, they are already up around 480 anyway, and skip the tranny?. Better yet, use a fronius primo inverter that does 1kv strings. With 1 kv, you just couldn't have the inverter inside the house.
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

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