What happens in case of a power oversubscription on APC Rack PDU 9000

[tkriegbaum]

Hey there,

I have a very basic question: Let's say we have a rack with two 16A cirquits. Each one equals about 3.5KW.

When the operational load is about 4.5 KW f. i. balanced over two power supplies in each rack device.

When now one cirquits fails -> the remaining one is overloaded.

What happens then?

Will immediately the fuse of the remaining will go down as well and the rack will be completely down?

Or does the PDU 9000 continuously keep delivering 3.5KW and just not more? If so how will it distribute the available power to the used outlets? like equally or satisfy only one outlet after another unt turns off what it cannot handle?

I am aware that it is the connected machine that requests the power in realtime and of course it is up to the intelligence to the device if it goes down when not getting the requested power or if it throttles down somehow.

Anyway I like to get an idea how the PDU acts in different kind of overload situations.

Finally that raises the question: In order to guarantee no power outage (as much as we can): Would you, in a rack with two cirquits conservately not to oversubsribe the capacity of one cirquit?

Thanks in advance,

Thomas