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View Full Version : What size wire do I use for a new 200amp service 550ft away?


Martin143
Aug 9, 2009, 12:59 AM
I want to run a new 200amp service wire to a shed 550ft from my meter. I have checked with the electrical company and the meter is sufficient to run this with my house, there is also an extra set of lugs. Also do I need to run this in condut. What would be better copper or aluminum.

tkrussell
Aug 9, 2009, 04:42 AM
Doesn't anyone ever have a shed or workshop close to home anymore?

A shed with a 200 amp service? Must be one hell of a shed.

550 feet is a long distance to deliver 120 volts, even 240.

The most important variable needed to calculate voltage drop is the running amp load.

Another aspect is motor load. While a motor may draw say 20 amps running, it will draw up to 60 amps briefly to start under load. A motor starting will affect the voltage drop and possibly prevent the motor from starting properly, if the wire is not large enough.

That being said, if I assume that a 200 amp would be loaded to the max allowed load on a 200 amp feeder, 80% or 160 amps, at 240 volts, wire size would need to be 1000 MCM aluminum.

If I assumed 50 amps at 120 volts, which could be more closer to a real scenario, then 500 MCM aluminum would be needed.


So what will be the amp load, and types of loads in this shed?