400 amps underground service 280' from transformer to meter

[DIEGO FRANCO]

im having a hard time to due a load calculation on a 400 amps service 280' from the transformer to the meter can

 

[don_resqcapt19]

The load calculation has nothing to do with the length of the conductors. Are you trying to do a voltage drop calculation?

 

[DIEGO FRANCO]

I have a customer that needs a 400 amps service and is around 280 ' away from the t pole

 

[DIEGO FRANCO]

Not sure the size of pipe and aluminum conductor

 

[LarryFine]

We usually start with "What is your calculated load?"

 

[electrofelon]

Hard to say without knowing any of the loads, but most of the time 350 MCM AL would cover it. Something like a big on demand water heater or resistive pool heater or a ton of electric heat might make me go bigger.

 

[DIEGO FRANCO]

customer needs at the end around 350 amps

 

[roger]

customer needs at the end around 350 amps

So use that for your calculation.

 

[Hv&Lv]

customer needs at the end around 350 amps

Connected load? My bet is they will never use more than 180 amps continuous.

 

[tom baker]

Residential or commercial? Who installs the UG?

 

[electrofelon]

Connected load? My bet is they will never use more than 180 amps continuous.

Yeah I used 150A. Quite unlikely it will get above somewhere around your or my figure.

 

[DIEGO FRANCO]

Residential and we have to install UG

 

[DIEGO FRANCO]

I just never have a cross that we have to run the UG that long 280'

 

[qcroanoke]

Residential or commercial? Who installs the UG?

Exactly! Is it your wire and subject to inspection
or is it the utility's and subject to their rules?

 

[electrofelon]

I just never have a cross that we have to run the UG that long 280'

Thats really not that far in these parts. I do 200 feet very frequently, have gone up to about 750. Does this service have any actual big loads on it or is it a typical novelty 400A service?

 

[zbang]

Yep, first question is whether this is spec'd by the PoCo and their rules or does it need to follow the NEC.

 

[Little Bill]

It's odd to hear the customer has to provide & install the conductors for UG. I deal with 5 or 6 different POCOs and all of them install the conductors. Some require us to provide the conduit but none require us to install the conductors. We pull a string and leave it in the conduit, POCO takes it from there.

 

[don_resqcapt19]

It's odd to hear the customer has to provide & install the conductors for UG. I deal with 5 or 6 different POCOs and all of them install the conductors. Some require us to provide the conduit but none require us to install the conductors. We pull a string and leave it in the conduit, POCO takes it from there.

We have had to provide and install the underground from a pad mount to the service equipment for commercial services for a long time. The only think the utility does is terminate at the transformer. Recently they have stated to require that for dwellings too.

 

[electrofelon]

It's odd to hear the customer has to provide & install the conductors for UG. I deal with 5 or 6 different POCOs and all of them install the conductors. Some require us to provide the conduit but none require us to install the conductors. We pull a string and leave it in the conduit, POCO takes it from there.

the other way around for me. The idea of the Poco pulling conductors to the meter socket baffles me, I think I've seen it once in
25 years!

 

[augie47]

IF your calculated load is actually 350 amps (rare on residential), to maintain a 3% voltage drop you would need parallel 300 kcmil AL and, if you don't reduce the neutral, it would take a 3" PVCconduit (assuming there is some Sch 80)