If you have a duplex outlet thats rated for lets say 20 amps, is the whole unit rated for 20 amps, or is each socket rated for 20 amps?

Edit: So if I had a circuit that had a 40A breaker on it, could I have 2 devices that both draw a max of 20A on the same duplex outlet?

  • Nobody mentioned the possibility that you could break the tabs on the sides of the outlet and feed the top and bottom receptacles from two totally separate 20A circuits. Jan 19, 2015 at 3:47

4 Answers 4


Each socket can supply up to 20 amps.

However, the total draw of everything on the circuit can also not exceed 20 amps.

Therefore, if you only have one device on the circuit, it can draw up to 20A from any one outlet. However, if you have a 15A device on the circuit, the remaining devices can only draw up to 5A.

Basically, the sum of the current draws for every device on the circuit has to be less then 20A.


the wire supplying the current and the breaker is rated for 20 amps as well

this means that max current you can draw is 20 amps before the breaker trips but you can draw it all from a single socket if need be

  • is correct, you CANNOT draw 40 amps from that outlet.
    – uncle brad
    Mar 7, 2012 at 11:53
  • So, restated concisely as a specific answer, each socket is rated for a 20-amp draw.
    – KeithS
    Mar 7, 2012 at 16:45
  • The wiring should be rated a lot higher, actually. In Au, common sockets are 10A, the circuit breaker is usually 15A and the wiring is rated to at least 30A.
    – staticsan
    Mar 9, 2012 at 2:13


Each receptacle is rated for 20A, and the whole device is rated for 20A.

So you can draw 20A from the top receptacle.

enter image description here

You can draw 20A from the bottom receptacle.

enter image description here

Or any combination less than or equal to 20A.

enter image description here

But you cannot draw more than 20A on any part of the device.

enter image description here

Looking at the guts of a receptacle, might make it a bit more clear.

enter image description here

When the tabs between the terminals are in place, a total of 20 amperes can flow through the duplex receptacle.

However, if you remove the tabs, each set of contacts is still capable of carrying 20 amperes. Which means if the receptacle is supplied by two separate 20 ampere branch circuits, you can power 20 amperes worth of load from each set of contacts.

  • Really? This seems like a significant safety hazard since 15A duplex receptacles are permitted on 20A circuits. Does this imply that under these circumstances, plugging 2 9A devices into the same receptacle would overload it without tripping the breaker?
    – dlf
    Jan 9, 2016 at 22:11
  • 2
    @dlf, EACH receptacle of a 15A duplex receptacle is rated for 15A. Just like the 20A in the examples above. A 15A duplex IS rated for 20A feed-through. The whole device is not limited to 15A. May 26, 2016 at 19:46

The other thing to consider is that residential setups are designed under the assumption that you will never max it out to capacity. For example, you might have 100amp service, yet if you add up the amperage of all the circuit breakers in your house, you'd likely find that the sum exceeds 200amps (100amps per phase, with split phase power in residential = 200amps). Similarily, each 15amp circuit will have multiple outlets capable of drawing 15amps each, even though the circuit is not capable of delivering 15amps to each outlet.

This differs from commercial/industrial where the systems are designed for total loads closer to the breakers' individual ratings, because the electrical systems are designed around the needs of equipment that will usually run all at the same time.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.