Utility transformer 100KVA

[CrazyRabbit]

The transformer I’m connected to is stamped 100KVA, which is about 426 amps. This transformer powers 4 houses with 320 amp service. This doesn’t seem like it is enough for four houses.

 

[miimura]

This is typical industry practice. There will be very few times when all 4 houses are drawing more than 100A. Even then, the transformer can survive running significantly over the nameplate rating for an hour or two. Coincident high draw from 4 houses is unlikely to last longer than that. I would venture to say that a 100kVA transformer serving 4 houses is a better solution than two 50kVA transformers serving two houses each.

 

[Troglodytes]

For comparison, my area of a late 1980's neighborhood: 50kva transformer five houses with 200A service each. I expected that the local utility was going to tell me 'transformer upgrade time', but my 17.64kwh system didn't necessitate it.

 

[zƬesla]

When we installed 17.5 PV earlier this year, utility charged to upgrade pole transformer from 10 to 25. It services 2 houses and has 2 buildable lots next to it; lots have been empty a while though.

 

[SoCal Dave]

I have a pool, 3 ponds and 2 AC units with a 200A panel. My peak usage yesterday was 4.5 kWh or 18.75A. 426A will easily cover 4 houses unless they all turn on their ACs, arc welders, electric stoves/ranges, spas all at once.

 

[getakey]

you need to look at peak kW, not kWh
I have 2 AC units and hit a peak of 11kW or about 90 amps yesterday (99 degrees out). However, my usage over the hour was probably 5 or 6 kWh

wait, they are probably 220V, so 45 amps

 

[JeremyWhaling]

Transformers are one of the few electrical components that can be somewhat overloaded without issue, as long as it is cooled off in the night or lower load period.

Of course, sustained overload can (at minimum) shorten the life of the transformer or cause failure (sometimes spectacularly).

 

[SoCal Dave]

you need to look at peak kW, not kWh
I have 2 AC units and hit a peak of 11kW or about 90 amps yesterday (99 degrees out). However, my usage over the hour was probably 5 or 6 kWh

wait, they are probably 220V, so 45 amps

I know it is an approximation as it is an average over an hour. As the number of houses increases the more likely the averages are coming into play which is what the electric company is depending on.