DIYbanter - View Single Post - Load capacity of 200-amp panel

Bud--

wrote:
On Oct 28, 1:37 pm, bud-- wrote:
wrote:

Yes. You have a 3 wire service cable coming into the house. Use
Kirchoff's law and add up the current coming into the house at any
point in time under any conditions through that cable any you have a
max of 200 amps. Add up all the current leaving the house at the
same point in time and you have a max of 200 amps. In my world,
that's a 200 amp service. You don't measure 300, or 400 by counting
electrons twice.
And also, to support a max of 400 amps of 120volt load in the house
which is the hot topic, you have to have the special case where the
loads are perfectly balanced so that 200 amps is on each side.
To get the max of 200A of 240V load you have to have the special case
where the loads add up to 200A. The discussion is about the special
cases of a fully loaded service.

And
then you in fact have a SINGLE circuit with 200 amps flowing in on one
hot leg, throught the loads in series, and back out the other hot
leg. Nothing flows in the neutral. Again, in my world, that's 200
amps flowing in the service, not 400.
What did the OP want to know?
IMHO, the OP was asking how many amps of 120V load you can hang on a
200A 240V service. The correct answer is 400.

--
bud--

The correct answer is actually 400 amps of 120volt load IF THE LOAD IS
PERFECTLY BALANCED. IF it's anything less than perfectly balanced,
you can not support 400amps of load. If it's totally unbalanced, you
only get 200 amps.. Partially ballanced, you get between 200 and
400. The only way you can get 400 is if it is perfectly balanced so
that the 120volt loads are in SERIES and appear as a 200 amp 240volt
load.

Agree?

Yup.

Have fun with JIMMIE.
Surprising how a simple question is so controversial.

I don't see the series argument as particularly interesting, but maybe
again POV.
In a slight tangent, if you have a 200A 3-phase 120/208V Y panel and
load A-phase at 200A 120V, B-phase at 200A 120V, and C-phase at zero,
you will have 400A connected 120V load and a 200A neutral current.

The same is true with a single phase panel fed by 2 legs of a 3-phase
supply. I believe you can get that in large apartment complexes that
have a 3-phase service.

And I hesitate to say it again, but I understood Doug to have said the
same thing as in the previous 2 posts. I think he used "parallel" once,
which I understood to mean "combined" (200+200), as applied to the 120V
loads. I don't remember he ever other wise implied there was 400A in the
neutral.

--
bud--