# Question10a cable on 15a power supply

#### MatiasLGonzalez

Hello everyone, I've been planning on doing a built on a modded case (Power Mac G5) and I've been trying to reuse most parts, I've been planning on getting this power supply

https://www.amazon.com/SilverStone-Technology-SX800-LTI-Titanium-Capacitors/dp/B01NALZ89C/

Problem is that the original power cord of the case is a 10A 250V cable and this power supply has a 15A 250V input, would it be totally wrong to use this power cord with this power supply? Where I live we use 220V, so in worst case scenario it would be using 3,63...A right? I actually got this cable (original one from the case) because it said 16A 250V, but that's only on one side, on the other side (the side that goes to the PSU) it says 10A.

#### Lutfij

##### Titan
Moderator
You should be using the power cord that came with the PSU you've linked. The reason you have an amperage rating is to notify the end user that after X Amp's the fuse will give out. So using a 10A cord on a PSU that needs 15A is a BIG no-no.

#### jay32267

##### Splendid
Here's how I would figure it out.
800 watts output @ 92% efficient = 870 watts input power

I=P/V
I =870/220=3.95 amps.
This should be worst case according to the numbers.

#### MatiasLGonzalez

You should be using the power cord that came with the PSU you've linked. The reason you have an amperage rating is to notify the end user that after X Amp's the fuse will give out. So using a 10A cord on a PSU that needs 15A is a BIG no-no.
Will the power supply draw 10A though? And do you know why does it say 16A on one side of the power cord btw

#### ConanLock

##### Commendable
I was thinking the same as jay32267. There's no way any standard PSU out there would draw over 5a, even at full power, in the 200+ volt areas. Here in the UK, I usually use 3a or 5a fuses on all of my PC power cables.

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#### jay32267

##### Splendid
Will the power supply draw 10A though? And do you know why does it say 16A on one side of the power cord btw
According to the numbers it will draw 3.95 amps max.
If it says 16A on the side of the cord I would think the cord is rated for 16 amps.

Here's the thing.....at 220 volts you can get away with conductors almost twice as small as here in the US @ 120 volts.

#### MatiasLGonzalez

Here's how I would figure it out.
800 watts output @ 92% efficient = 870 watts input power

I=P/V
I =870/220=3.95 amps.
This should be worst case according to the numbers.
Ohhh I didn't know power supplies where rated at the power they supply given their efficiency, I thought it was 95% of 800w ie

#### jay32267

##### Splendid
Ohhh I didn't know power supplies where rated at the power they supply given their efficiency, I thought it was 95% of 800w ie
I got the 92% number from the manufacturer's website.
You divide the output by this number to get the input power.
Then you divide the input power by the input voltage to get the input current.

#### MatiasLGonzalez

I got the 92% number from the manufacturer's website.
You divide the output by this number to get the input power.
Then you divide the input power by the input voltage to get the input current.
Yeah, I get it know thanks!