PSU input amp / household current usage

[mastaBlasta]

My issue is simple yet very frustrating.

I live in a small apartment in an old building and the maximum current coming to my fuse box is 20 Amps. Yes I = 20A! Two circuits, 10 amps each.

I am building a new SB machine with specs similar to other folks here, and have gotten stuck on the power supply. Many of the 600W+ PS say 10 amp input which is simply too high.

I'm hoping that that's not true, or that it only sucks in 10 Amps under ultra heavy load, and under normal use is 5A or something.

What kind of average amp use can i expect from most mainstream PS. Is there some kind of hardware solution, like an adapter of sorts that will up the ampage by using more voltage?

Any help is greatly appreciated.

 

[Gorankar]

The 10 Amp input rating is going to generally be a worst case rating. It usually means that it can pull up to 10 Amps, not that it will pull that many.

While gaming, my sig pc #3, according to the UPS it is connected to, draws right at 700-800 watts all together. That is all three monitors, the pc itself, surround speakers, a router, a switch, a cable modem, and my cordless phone base as well. That is around 6 - 6.5 amps @ 110/120v.

You should be fine supposing you have little else running on that line. A UPS with AVR might help reduce issues with your PC if circuit breaker popping is a common occurrence for you.

 

[plugwash]

What country are you in? when you say 10A what voltage is that at?

Assuming 80% efficiancy you would expect a 600W PSU to draw about 750W from the mains at full load. Assuming the power factor is 1 (it should be fairly on a high quality PSU) at 240V that would be 3.125A at 120V it would be 6.25A at 100V it would be 7.5A and at 80V it would be 9.375A

So 10A would be about right for a worst case current draw (the power factor won't be quite 1 and the efficianty tends to drop off with reducing voltage, afaict the 80 plus guys measure at 115V input) but that worst case is likely to be rarely seen in practice. Most people don't load their PSUs to the max and afaict voltages rarely drop that low (at least not for more than a few seconds and breakers don't trip the instant you put a small overload on them)

 

[Blue Fox]

The plug is rated for 10A. Your system will never draw that much or anywhere near it. The theoretical adapter you mentioned isn't possible as watts = V x A.

 

[Disturbed_One]

If it helps, I'm currently pulling 1.3A @ 117.2 Volts. (According to my kill-a-watt)

Anything plugged in only pulls as many amps as it needs.
So basically, you have 20 amps to go around.

 

[mastaBlasta]

Thanks for the great replies. This quiets down my worries. Btw I am in the US (Virginia), so it's standard 120V.

And I am definitely going to buy a good, high quality PSU. With these you really get what you pay for.

 

[investinwaffles]

Yikes, I would be toast with only 10A on each circuit

You should be more than fine though. Like everyone said above, 10A is an absolute worst case situation like if the PSU circuits or something. 1200w is a decent amount of power for one PC to be drawing (unless you have 4 or 5 GPU's and dual CPU's or something stupid like that). I doubt you will ever be able to push that even with 2 or 3 computers plugged in.