16amps on a 13a socket

[andyr123]

if you plugged in 2 plugs of heavy appliances of 2kw each (say a tumble dryer on full heat, and a 2kw Fan heater) into a double socket wall outlet 2x2kw @240vac = over 16amps - yet a 13amp twin socket outlet is designed to plug in 2x 13a plugs , how is that? there would be a tremendous amount of heat after a while with 16amps ... but its called a 13amp socket even if its a twin socket outlet, not a 26amp socket. - there is not even any failsafe design to the 13a twin socket to dis-allow/disable end users of plugging in 2x2kw (2x8amps) of plugs into a 13amp double socket outlet - let alone some appliances like kettles can use up to 3kw of power.

I'm just curious is all it is.

 

[plugwash]

There doesn't seem to be any standard specifying the total current rating of a double socket, BS1636 is notablly silent on this point. Howeverit does specify that double sockets should be type tested at a total of 20A, with 6A in one side and 14A in the other. Still this is far short of the maximum possible total that two appliances could draw.

I think the saving graces that stop this being a huge problem in practice are

1. the materials usually used in the UK to make socket outlets and their backboxes are generally pretty resiliant when it comes to overheating. Overheated sockets often turn brown/black or crack, but they don't generally fall apart completely or set themselves on fire.
2. Appliances that draw the full 13A and do so for a long time are relatively uncommon.

 

[andyr123]

There doesn't seem to be any standard specifying the total current rating of a double socket, BS1636 is notablly silent on this point. Howeverit does specify that double sockets should be type tested at a total of 20A, with 6A in one side and 14A in the other. Still this is far short of the maximum possible total that two appliances could draw.

I think the saving graces that stop this being a huge problem in practice are

1. the materials usually used in the UK to make socket outlets and their backboxes are generally pretty resiliant when it comes to overheating. Overheated sockets often turn brown/black or crack, but they don't generally fall apart completely or set themselves on fire.
2. Appliances that draw the full 13A and do so for a long time are relatively uncommon.

Is the 2.5mm wiring behind the double 13a socket OK for it? - I see 2.5mm is good for 24amp single phase but does that double to 48amp on a ring circuit? - if you plugged in 2x 3kw appliances that would amount to 25amps wouldn't it? so even if the socket would withstand it what effect would that have on a 2.5mm T&E

 

[EFLImpudence]

Is the 2.5mm wiring behind the double 13a socket OK for it? - I see 2.5mm is good for 24amp single phase but does that double to 48amp on a ring circuit? - if you plugged in 2x 3kw appliances that would amount to 25amps wouldn't it? so even if the socket would withstand it what effect would that have on a 2.5mm T&E

2.5mm² T&E has a maximum current carrying capacity of 27A.

 

[andyr123]

2.5mm² T&E has a maximum current carrying capacity of 27A.

Thanks. I was getting info from here:

Cable Size & Current Rating Chart

Cross Sectional Area of Conductor (mm2)Approximate Overall Diameter of Insulated Cable (mm)Current RatingSingle Phase (Amps)Three Phase...

www.spwales.com

 

[andyr123]

2.5mm² T&E has a maximum current carrying capacity of 27A.

If you have a ring mains to the socket does that double it up to 54amps rating or is the rating still 27amps?

 

[flameport]

If you have a ring mains to the socket does that double it up to 54amps rating or is the rating still 27amps?

A ring circuit is protected by a 32A device. That is the maximum current for the circuit.

 

[plugwash]

2.5mm² T&E has a maximum current carrying capacity of 27A.

Depends on installation method, that figure is for "Method C", basically wires either clipped direct to a wall or burried in plaster.

https://www.doncastercables.com/technical-help/4 has current ratings for different sizes of T&E with a few common installation methods.

If you have a ring mains to the socket does that double it up to 54amps rating or is the rating still 27amps?

In theory it would, if the load was perfectly balanced, but the load is rarely perfectly balanced.

IIRC the dispensation in the regs that allows for rings that would otherwise violate the normal requirements for overcurrent protection requires.

* The cable to be at least 2.5mm (unless MICC)
* The cable to be rated at at least 20A
* The installer to judge that sustained overloading is unlikely.
* The protective device to be no more than 32A (usually it's either 30A or 32A depending on age).

 

[EFLImpudence]

Depends on installation method, that figure is for "Method C",

Irrelevant.

You will note I said:

2.5mm² T&E has a maximum current carrying capacity of 27A.

In reply to:

I see 2.5mm is good for 24amp single phase

basically wires either clipped direct to a wall or burried in plaster.

So?