On Monday, October 31, 2016 at 8:00:09 PM UTC-4, wrote:
On Mon, 31 Oct 2016 13:35:20 -0700 (PDT), wrote:

On Thursday, October 22, 2009 at 9:02:51 AM UTC-7, JayB wrote:
This came up elsewhere and I am just curious about what the answer is.

If someone has a main service panel with a 200-amp main breaker, how many
amps of service can that panel actually service?

I am probably not wording this correctly, but I thought that I remember
something about a 200-amp main breaker actually being okay for 400 amps of
service since there are two separate circuits coming in (a 240-volt service
split into two 120-volt circuits in the panel box).

If you apply 240-Volt to the load and have 200 Amps current, you've got 48 KVA. If you apply 120-volt and have a 200 amps, you've got 24 KVA. If you connect 200 Amps load to each of 120-volt leg, you've got 48 KVA total.
In other words, if you balance the load and use only 120 volt
loads, you can run a maximum of 400 amps.
If you run only 240 volt loads, you can only run 200 amps

In reality there is never more than 200 amps of current flowing
in a 200A service. If it's a balanced load, the same 200A is flowing
through half the 120V loads, then on through the other half of the
120V loads. There is never more than 200A flowing in the service
conductors. You can support 400A worth of 120V loads, but it's
just 200A being counted twice.