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Maximum socket outlets

Discussion in 'General Electronics Discussion' started by Daniel church, Feb 25, 2017.

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  1. Daniel church

    Daniel church

    Feb 25, 2017
    Hi guys, I'm struggling to find a definitive way of calculating the maximum number of socket outlets allowed to be connected to a given circuit breaker. Can anyone direct me to a table where I might be able to find the answer or an equation???
  2. BobK


    Jan 5, 2010
    Well, as soon as you have more than 1 typical socket and breaker you can overload it, so the true answer is probably 1. But in practice, I know more are allowed by code. You would have to check the electrical codes for your location.

  3. Minder


    Apr 24, 2015
    I see you are in Australia, do you use the 13a ring main system that UK uses?
  4. Externet


    Aug 24, 2009
    Just in case you have a misconception, a circuit breaker does not 'supply' a number of Amperes; it is there to protect the wiring.

    If the outlets use 1 Ampere each, you can have 20 outlets on a 20 Ampere breaker before trips.
    If the outlets use 10 Amperes each, you can have 2 outlets on a 20 Ampere breaker before trips.
    davenn likes this.
  5. Daniel church

    Daniel church

    Feb 25, 2017
    Thanks for your responses everyone, yes I am in Australia and aware that the breaker is there to protect the circuit.

    I just read through all our course content last night and there was no mention of the maximum allowable outlets connected to a 16 or 20A breaker but when I got to the content quiz there were 3 or 4 questions relating to this. If someone can tell me where I can find the info that would be great, so far I have had no luck, even in the AS3000 Wiring Rules.

    Thanks again!
  6. Bluejets


    Oct 5, 2014
    No ring main in Aus M. There is no maximum number of single phase general purpose outlets for a given circuit size cable. Used to be in the days of fuse protection. Circuit breaker becomes one limiting factor which now must include safety switch protection. The more important factor to consider is the route lenght of the circuit for calculation of earth loop impedence. This can get you by the short and curleys quicker than you think.
    davenn likes this.
  7. Wilksey


    Mar 3, 2010
    As people have mentioned, it depends on the number of devices and their power rating that you are planning on plugging in!

    If you have a single 16A breaker feeding a bank of sockets, and one of those sockets is taking 5A, you have 11A effective to distribute across the other sockets, though I would allow a bit of overhead!
    Also, inductive loads can cause havoc with circuit breakers (things with motors in, lawn mower, washing machine etc), especially if your earthing is not correct. Not sure if you are the same in AUS, but in the UK we have neutral -earth return at the substation, meaning that somewhere back along the line the earth and neutral are connected together.

    Whoever wired the house I am in wanted to be really sure, the kitchen, built on an extension, has 3 circuits (4 including lights), one for the sockets, where the toaster, microwave etc plugs in, one for the washing machine + dishwasher, and a final circuit feeding the fridge and freezer (two separate units), we have a gas cooker, so no big 40A breaker to worry about! The rest is simple, upstairs lights and sockets, downstairs lights and sockets, i've added 2 more, one for outside lighting and one for the shed electrics.
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