amp service size

[maud gonne]

Electrician wants to know what size service we will want for our proposed 800 sq ft house: 100, 125, or 200 amp. I have no idea. Part of the 800 sq ft will be a small shop. Suggestions?

[Rob Tucker]

Why go with the smallest? Do it once. Do it right. No telling what the property power needs will be in the future.
The cost difference between a 100 amp panel and a 200 amp panel is minimal.

[Hunt Stoddard]

I have a related question: if you're upgrading from a 100 amp panel to a 200 amp panel, will the lines from the transformer need to be upgraded as well?

[kalakoa]

HELCO would have to upgrade the drop to your house; if the upgrade tipped the local balance, they might also have to split the low-voltage line and add another transformer.

In any case, it's "obviously" cheaper to install 200A service at today's prices -- at the very least, a future upgrade means new permits in addition to more expensive parts/labor.

That said ... unless that shop has a kiln, big welder, or massive power tools, 100A service is probably enough.

[maud gonne]

Thank you Rob - just the advice I needed! Common sense, of course. Especially since the cost difference will be minimal - I didn't have a clue.

[EightFingers]

What will you be running?
100 amp will be fine.

[maud gonne]

Well, it's just a small house. But it will have a shop for woodworking, and perhaps for some other building type projects. I like the idea of "Do it once. Do it right. No telling what the property power needs will be in the future."

[K2man]

I recommend installing a 200 Amp panel. I don't know HELCO's practice, but I currently work for an electric cooperative (utility), and we use the same wire for 100A or 200A panels. There's more to designing a proper service than just wire size, but the cost of a 200A panel over a 100A with installation is probably $200 or so.

K2man

[terracore]

"No telling what the property power needs will be in the future."

Or what they will drive. Some car chargers use 30 amps, fast chargers can use 80, and ultra fast chargers haven't been defined yet.

It will be an interesting problem for the Europeans to figure out when their homes are wired for 80 amps, their grid is pretty much saturated, and some countries have banned sales of gasoline vehicles by 2040. As it is they can run either their car chargers or their stoves, but not both at the same time.

ETA: either

[maud gonne]

Good point, Terracore. I don't trust the aging US grid to be able to handle the projected trend to electric cars. Makes me question the environmental community's touting of them. Not that fossil-fuel vehicles are better... Sorry to veer off the topic for a second.