Good day,

When planning a feeder and load for a sub-panel, should the panelboard be considered a multi-outlet device and therefore you would limit the load to 80% of the breaker used in the main service panel breaker.

For example: MSP Breaker = 100 Amps. Sub-panel load not more than 80 amps?

If not, why not? I'm trying to prove a point to a relative.

A panelboard is a mulit-outlet device?

Here is a good place to discuss Main Panels and Sub Panels.

There are no such things.

Better to think of a "Main" Panel is a panelboard that happens to have the Main Service Disconnecting Means in it.

A "Sub" Panel happens to be a panelboard that does not have the Main Service Disconnecting Means in it.

My point is, they are both to be treated the same.

80% derating factor is only for loads to be determined as continuous, or runs 3 hours or more, plus 100 % of loads that are not continuous.

I know, I know, it gets confusing.

Of course, one, I am older the older school, and derated everything 80 %, plus all I do is commercial and industrial, and it all is derated 80%.

I digress. Back to panels, it don't matter if it is a main or a sub, rated them the same.