# Whats the relation between AC power strip current rating and DC output current from the PSU connected on

this is kind of a noob question:

I have a power strip (extension cord from my wall AC outlet) that is rated for 250V 10A. Over this power strip i'm connecting a power supply that gives an output of 12V 20A.

What's the relation between the power strip current rating and the PSU one?. I mean, how could you state the needed value for the power strip based the PSU current rating?

It's enough to just calculate the power consumption in Watts on the PSU (Vout * Output current) being lower than the one rated for the power strip?

(I'm not connecting anything else besides the PSU on it).

Greetings.

• Appliance AC current ratings are for breaker rating at max load and not what is actually flowing when lightly used. – Tony Stewart Sunnyskyguy EE75 Oct 1 '17 at 22:56
• You need to look at the PSU's input current rating since the input of the PSU is what is connected to the power strip. – user253751 Oct 2 '17 at 0:19

Yes. Power requirement of the PSU is $P = VI = 12 \cdot 20 \ = 240 \ \mathrm {W}$.
On 230 V mains the current required by the PSU is $I = \frac {P}{V} = \frac {240}{230} = 1 \ \mathrm {A}$ (plus a little).