Who knows, maybe in the Chicago area, wire is a controlled substance...
A typical house is wired with #12 or #14 gauge wire. #12 wire is larger than #14, the first is rated to be connected to a 20 Amp circuit breaker while the #14 is only able to be connected to a 15 Amp breaker. An electric clothes dryer and residential water heater is usually supplied by #10 gauge wire fed by a 30 amp circuit breaker.
If it's a regional thing, I'll be quite surprised. I suspect the person in electrical may know less than you about wire and grounding. The Home Depot here in my end of Seattle sells a wide range of copper wire product starting at the small #14 up to and beyond the much heavier #2 (which is usually used to connect service entrance panels and heavy industrial loads) The stock number at Home Depot for a whole roll of #10 bare copper wire is SKU# 712-534. Next time I go to the local store here in Seattle, I'll get the 'per foot' SKU (store keeping unit, ie. stock number) for you. I expect to find it in the electrical department on or near the 'wire machine' which is a motorized storage rack with spools of various types of wire than are sold by the foot.
http://www.homedepot.com/Electrical-...kuId=202895697
I'll also get the SKU for the same wire with green insulation.
(After I retired, my wife put me in adult day care at Home Depot for about a year. It was the best deal she could find to get me out of her hair for a bit.
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