Rick wrote:
I had a garage built and am wiring the building with 200A service
myself. At Lowe's, they have a sign that says the lead-in cabling for
200A service needs to be 4/0 - 4/0 - 4/0 - 2/0 aluminum cable. But,
one of their workers says that is wrong that the service cable must be
that size, but in copper. Anyone know for sure?


You don't provide enough information to answer the question. Is this
cable to be used before or after the first disconnecting means? Is the
service to your home to be single phase or three phase? Is the service
supplied via overhead or underground conductors?
--
Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous
for general use." Thomas Alva Edison