I need to install a 100amp sub-panel in a shed I am building. The length of the wire run is approx. 230 feet and the sub-panel I have purchased is rated for 100amps max and does not have a provision for a 'main' breaker. I will install a 100amp breaker in the house main panel.
I used the calculator at the electrician.com site and think I can get by with #1 al awg wire. The local stores around here claim they do not stock #1 al because no one uses it. I have no problem with moving up to 1/0 al for the 100amp service to the sub-panel.
The problem with the 1/0 al is that the wire will not physicaly fit into the 100amp breaker. I was told by the electrical supply store that I could de-rate the cable by clipping one or two strands off of the end until the cable would fit into the breaker and that this method was routine and would not be an issue with the building inspector. I have not discussed this matter with the building inspector yet as I did not wish to sound like a total idiot in the event the info I have been provided by the supply store is incorrect.
I cannot see how de-rating the cable accomplishes anything other that allowing the cable to fit into the breaker. My goal was to use a suitable size cable to minimize the loss due to the length of the run. It would seem to me that if I have to reduce the surface area of the cable at the breaker I might as well have used #1 al to start with.
Any suggestions would be appreicated on how to make the 230 foot run with an acceptable loss at the sub-panel end.
At this time the best that I can come up with is to do what the electrical supply store suggests or:
Install a 125amp breaker in the main house panel Run 230 feet of 1/0 al wire Ditch the 100amp panel I purchased Purchase a sub-panel rated for 100 or 125 amps with the provision for a 'main' circuit breaker Install a 100amp circuit breaker in the sub-panel as the main disconnect for the sub-panel
Thank you for your time.