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Posted By Topic: 32A socket on a 20A breaker

Jan 09 2019 06:50

Went to do a job at a cowshed replacing a damaged 32A socket.

When I got there the outlet is only fed from a 20A circuit breaker. There is nothing else on the circuit.

Is it alright to just replace the outlet or should I be upgrading the cable and circuit breakers to suit?

Jan 09 2019 08:25

I think it depends entirely on what kind of cable it is, what size it is and how it is installed

Once you know that you can work out the CCC and from there decide if the original one was installed appropriately or if it can be upsized

Just because it's a single 32A socket on a 20A breaker doesn't mean you can simply upsize the protection that is quite possibly that size for a reason

Jan 09 2019 08:29

Ah, I just re-read the question and think maybe I misunderstood what you asked

That's what I get for trying to be helpful at 8 in the morning when my daughter has kept me up


Jan 09 2019 08:43

Octane Outlaw was right the first time. There is nothing unsafe or non-compliant about using a 20 A circuit to supply a 32 A socket. Circuit protection is for the cabling of the circuit, and is not directly related to the fitting(s) being supplied, which may have been selected for reasons of interchangeability rather than current rating. You could usefully ask what sort of equipment gets (or is expected to be) plugged in; and whether a 20 A socket would be adequate.


Jan 09 2019 09:10

Yeah the cable is 2.5mm2 that was what made me pause when going to hook it up (thinking it was a bit light). So the Circuit breaker and cable are sized correctly for each other.

Thanks for the reply's, as always very helpful.

Jan 09 2019 17:22

It's probably not really fit for purpose. You have the potential of plugging a 32A appliance into a 20A circuit.

Jan 09 2019 18:42

True enough; but depends on wht the "purpose" is. Lots of places have standardised on plugs, especially 3-phase; so that any appliance can be used anywhere without need for adaptors. As long as no-one wants to use eg a big welder on the smaller circuit(s), no problem.
And if they do, the protection soon identifies the error.
The alternatives would be either to run all circuits in cable heavy enough for full rating of sockets, or to have "socket clusters" with variety of ratings at each point; neither option being cheap. Or use adaptors that keep getting lost.


Jan 10 2019 21:51

" It's probably not really fit for purpose "

'Probably not really ' .... Now there's an oxymoron.....

If the purpose of the outlet is to connect a load less than 20amp it is probably really more than totally safe and fit for purpose.

If the purpose of the outlet is to connect a load greater than 20amps, then yeah nah it is probably even definitely not really fit for purpose.