480V in Residential

[Castrovinci]

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)?

 

[user 100]

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.

 

[ptonsparky]

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.

 

[electrofelon]

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.