wrote:
I am doing a significant kitchen upgrade and the contractor has
recommended that I upgrade the electrical service to 200amp. I've had
3 electricians out to quote on the work---and received 3 very
different opinions and prices. Two have told me it is not necessary
to upgrade the main power line in the house from the meter to the load
center. The other one says I must.

I currently have 150amp service. The meter and the load center are
separated by about 50-feet. The wiring from the meter to the load
center is 2/0 aluminum. I work for a major residential electrical
equipment maker (starts with a "S" and ends with "iemens")...and our
construction sales people tell me that the latest version of NEC
requires 4/0 aluminum wiring for 200amp service.

What is up with 2 of these contractors telling me it is OK to upgrade
without replacing the existing 2/0 wiring?

Is there some sort of grandfather provision in this situation?

If the price difference wasn't so much it would be a no-brainer. But
at $3,500 vs. $750 it's a lot harder to go with the cadillac solution
simple because it is the cadillac solution....

Does anyone have any guidance on the issues and realities of this
situation?

Hmm. Disclaimer first - I'm a naval electrical technician, not civilian,
so am not intimately familiar with civilian code requirements. Further,
I'm Canadian, and if you're not, some of your code requirements may vary.

That said, check out this website:
http://www.friesen.com/manuals/allow...n%20Free%20Air

Depending on your insulation type and ambient temp, you'd need at least
3/0 to meet the requirements, and 4/0 gives you only a 30-amp safety
margin. As I said, I'm not familiar with the details of the NEC, but in
the Navy we'd be using the 4/0, since we have to assume that all loads
are energized at all times. There may indeed be some kind of
'grandfathering' provision, but I'd rather not create an electrical fire
risk.

Yours aye,
W. Underhill

--
"Take sides! Always take sides! You may sometimes be wrong - but the man
who refuses to take sides must *always* be wrong! Heaven save us from
poltroons who fear to make a choice!" R.A. Heinlein, "Double Star"