# Power cable for 5V 20A power supply?

I bought a switching power dupply (SMPS) rated at 5V | 20A | 100W.

But it seems I don't understand how power supply works. I need total of 18A on output, but that seems to be over the limit of standard 16A | 220V wall outlet's limit.

How would I power this supply without burning my house down? I bought fuses and relays but that can only handle max at 10A.

Reason for such high amperage needed:

I was going to power 300 LEDs that require 5v 60mA per LED. I'm planning to make it in 2 parallel structure, giving me 150 leds each side. It turns out I need 5v each side with 9A flowing each side, totaling 18A. So does two 9A merge on outlet's side?

• ... What's 5V times 18A? What's 220V times 16A? Commented Jul 18, 2017 at 15:39
• 18A at 5V is 90W. Which is about half an Amp from 220V outlet. Commented Jul 18, 2017 at 15:39
• It will consume ~0.5 A on the primary (mains) side att full load. Up to 10 A/mm^2 is fine heating-wise, but you will be limited by maximum allowed voltage drop in your 5 V system. Commented Jul 18, 2017 at 15:39
• @Sysnaptic You need to consider the high current on the output, of course and use the proper cable. Commented Jul 18, 2017 at 15:44
• @Sysnaptic Note that you do need heavy wires capable of supporting 20A on the 5V side! Commented Jul 18, 2017 at 16:37