In article TSCae.11155$c24.1210@attbi_s72,
Keith Carlson wrote:
"DL" wrote in message
news:Ksyae.4804$lz1.333@lakeread01...
I guess what puzzles me with all the questions I have been getting about
what I am planning to do will cost more or it is not necessary. I would
understand it if I was going to do something that potentially dangerous,
but
David, I think a lot of guys are just looking at the plan for 400A service
and scratching their heads wondering "why". Because most of us try to things
in a safe, yet cost-effective way, I think it's natural for people to
question it.
5000 sq ft is a big house. But there are plenty of homes around me in the
3000-3500 sq ft range, being built with 200A service. And probably a bigger
factor than the size: are there more people living in the 5000 sq. ft. house
than a 3000? More concurrent use of electrical power?
The electrician who came out to inspect my last add-on circuit told me most
of the newer houses with 200A panels will probably never even see 100A being
drawn.
Make it 150A and I'll agree. but hitting 100A is all too easy nowadays, when
you start considering all the kitchen small appliances, personal computers
and especially _printers_, and all the other 'consumer electronics' to be
found in a home. individually, they don't draw a great lot, but there are
so _many_ of them. Example, I've got *sixteen* 'counter-top' appliances
in the kitchen. that's admittedly on the high side, because I am a bit of
'gadget happy' type, and, for example have two microwaves. Given that set-up
it's not unreasonable that I might have 6-7 of them in simultaneous operation.
at in excess of a kilowatt each. Plus maybe the dishwasher. Let the
refrigerator and/or freezer decide to cycle, and I could hit 50A @ 240
just in the kitchen. Without considering a possible electric stove.
Add the air-conditioning, and it doesn't take 'hardly anything' additional
to go over 100A.
They install a 200A service panel mainly to have more spaces for
breakers. (and I'm assuming the cost for a 200A main breaker and the larger
wire size in a new installation is relatively small).
The incremental difference in the cost of the panel and main breaker is
under $100 U.S. The cost of larger feed-wire from the transformer is maybe
$1/ft. I doubt the total cost increment would exceed $1,000.
But what's the cost of upgrading from 200A to 400A service? Compared to
another solution like two 200A panels to make room for more
circuits/breakers? Someone else's advice about a load calculation is right
on the money. That's the starting point, and I'd be surprised if the
electrician hasn't done it. If it were my money, I'd want to see the
reasoning behind his recommendation.
I find it _not_at_all_ difficult to believe -- i.e. that it *is* entirely
reasonable -- that 200A would be insufficient for a property of that scale.
Postulate Central A/C, that's gonna be an easy 70A (at 240) right there.
just for the compressor. (I grew up in a circa 1600 sq ft house, that had
two-zone fully independent HVAC -- the AC for _each_ zone was a dedicated
40A circuit for the compressor; plus there was an additional 20A (120) A/C
for a room that was exposed on 5 sides.)
Throw in a couple of electric "major appliances", say a stove at 50A, and
a clothes dryer at 30A, and you've got an easy simultaneous load of
150A.
Now, lets add some other basic necessities:
1) The GFA furnace blowers, or circulating pumps
for a hot-water radiator system -- for a house
of that size, 15A (120v).
2) Washing Machine, to match the dryer
10A (120v)
3) Refrigerator 13A (120v)
4) separate freezer 13A (120v)
5) dishwasher 10A (120v)
6) garbage disposer 8A (120v)
7) trash compactor 8A (120v)
8) Microwave oven 10A (120v)
There is roughly 90A at 120, or 45A at 240
We've now got a total load of 195A at 240.
And it is _entirely_ within the realm of reason that *all* those devices
could be running simultaneously.
Without exceeding a 200A utility feed, you've got whopping _10A_at_120_ left,
to run _everything_else_ in the house. Twelve 100-watt light bulbs.
You get a little more breathing room if the stove and clothes dryer are
gas-fired.
For a 'demonstrator' model where, for example, major appliances that
are present will _not_ be being used, I can see a developer 'cheaping out'
with only 200A service.
Start adding in power demands for a 'serious' shop, and there's no doubt
that 200A service is inadequate.
Yeah, 400A looks like overkill, but if it's the "next step up" from 200,
then that _is_ what you do.
If 250, or 300 service was available, it might have been sufficient, but
'why take the chance'. probably 75% of the cost of re-doing things is
in the labor. if materials for 400A cost _twice_ what 250A materials
do, it's only circa 10% of the total bill.
This is called "*CHEAP* insurance"
Particularly if amortized over the
expected lifetime of the work.