Basically I have an uninterrupted power supply (UPS) which has a 20amp plug and I know that the load on the UPS will NEVER exceed 15 amp (Bought it mainly because it can attach more battery units to it for extended runtime).

Anyway since I am moving to an apartment that does not have any 20amp outlet, and since I know that the load will NEVER exceed 15amp, I want to enforce this via a fuse/breaker inline or in the outlet so that it WILL trip before too much power is drawn from the outlet.

So I am wondering if such thing exist or if there is any recommendations here?

  • The fuse/breaker in the main panel will trip if you draw more than 15Amps on the circuit (given that it is a 15Amp breaker), so you shouldn't have to worry about it. Likely there will be more receptacles on the circuit (with things plugged into them drawing power), so the breaker will trip long before anything on the UPS can draw over 15Amps.
    – Tester101
    Commented Jun 23, 2011 at 23:32

1 Answer 1


Get a 20A to 15A converter cable, like this one: http://www.amazon.com/Conntek-1F515520-1-Foot-15-Amp-Adapter/dp/B00439KIF6

It is perfectly safe to plug a 20A device in to a 15A receptacle on a 15A breaker. If your device draws more than 15A, the breaker will trip. You can reset the breaker and try again, with a lower load. If you never exceed 15A draw, you'll be fine.

15A is a lot for a computer. You can use a Kill-A-Watt to measure your actual load, if you're curious.

  • 1
    normally I would not recommend altering a 20A appliance to fit a 15A outlet, but since it is a UPS plug strip, what Jay says is correct. +vote for kill=a=watt. Commented Jun 24, 2011 at 10:20
  • I used the ups information status display and the highest I've seen it go is 30-35% of the UPS capacity which is 665 watt or so, and I've checked, the PF on all of my PSU are at least 0.95 or so. So yeah, I'll look in getting an adapter like that.
    – Pharaun
    Commented Jun 24, 2011 at 21:31
  • Fifteen amps would be a lot for a computer, but after a power failure, depending upon the design of the UPS, it might draw a fair bit of power for the purpose of charging batteries in addition to anything the computer equipment itself would be using.
    – supercat
    Commented Oct 16, 2014 at 2:43

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