[cornedi]

I'm planning new residential construction in Ontario Canada.

I've searched the Ontario Electrical Safety Code Rule 8-200 for how to calculate a service size wire for 200 Amp service to a cottage size residence (1100 sq. ft.) with no success.

My need is to run 175 feet of underground wire from a 25KVA transformer to the first wall electrical pannel of the new construction. My wife and I will have usage of under 100 amps (typically 60 amps.) but would like the option to add structure in the future to maybe 150 amps total usage.

Except for occasional use of a table saw (220VAC) our needs are for 120VAC for typical household requirements.

How do I calculate the 200 amp wire size I'll need for the 175 feet distance?

Any feedback would be appreciated.
Thank you.

[tkrussell]

I cannot saying if CEC is any different, should be similar to the NEC here in the USA.

They recommend no more than 3% for a feeder, or 12 volts dropped off 240 volts.

#4/0 aluminum will work fine. We use a 4 wire direct burial cable called URD.