BS 1363 13A Socket Continuous Max Load

Both our washing machine and dishwasher draw 10 amps, those are the only appliances we have that draw more than 8 amps and they both do it for a limited time.

Electric vehicle granny lead chargers are limited to 10 amps, 3kW plug in domestic appliances are virtually non-existence, so maybe 13 amp sockets not being able to carry 13 amps for several hours isn’t actually a problem.

If the “special EV charging 13 amp sockets” can only  be used at 10 amps, then perhaps 8 amps is reasonable for the ordinary or general purpose 13 amp sockets.

What a fiasco ! Back in the good old days, I recall 13 amp sockets being used at a full 13 amps for hours at a time. Wash boilers, early washing machines, and 3 kw heaters.

How do they manage abroad ? How many amps can continental 16 amp sockets supply ?

How many amps can a 16 amp ceeform plug handle ?

broadgage: 
 

If the “special EV charging 13 amp sockets” can only  be used at 10 amps, then perhaps 8 amps is reasonable for the ordinary or general purpose 13 amp sockets.

What a fiasco ! Back in the good old days, I recall 13 amp sockets being used at a full 13 amps for hours at a time. Wash boilers, early washing machines, and 3 kw heaters.

How do they manage abroad ? How many amps can continental 16 amp sockets supply ?

How many amps can a 16 amp ceeform plug handle ?

The problem with BS1363 plugs is the fuse, which acts as a heating element at high currents.

If that was replaced with a brass slug, the plug would carry 13A all day, barely getting warm.

Many detachable appliance leads are supplied with 10 amp fuses in a 13 amp plug.

BS7671 only recognises 3 and 13 amp BS1362 fuses, but 5 and 10 amp fuses are often fitted or specified by manufacturers, I use 5 amp BS1362 fuses on a daily basis and have stopped saving the 13 amp fuses, leaving for the customers though they will almost certainly never need them.

Since fitting a modern consumer unit with MCBs twenty years ago I can not recall ever blowing a 13amp plug top fuse.  The MCB acts so much faster than the fuse.

Which is a pity because it removes a desirable level of discrimination.

Sparkingchip: 
 

Both our washing machine and dishwasher draw 10 amps, those are the only appliances we have that draw more than 8 amps and they both do it for a limited time.

Electric vehicle granny lead chargers are limited to 10 amps, 3kW plug in domestic appliances are virtually non-existence, so maybe 13 amp sockets not being able to carry 13 amps for several hours isn’t actually a problem.

I disagree. The defacto limit of 8 to 10 amps on a so called 13 amp plug and socket limits the design of appliances.

A washing machine or dishwasher with a full 13 amp loading, would heat the water more quickly and thereby give a shorter cycle time, an attractive feature for some consumers.

A tumble dryer with a full 13 amp input would dry the laundry in a shorter time, again an attractive feature.

A true 3 kw portable heater would be most useful for warming large areas.

And all of the above USED to be available and used back in the good old days, when 13 amp plugs and sockets could carry 13 amps.

And how long before pedantic inspectors start “failing” installations with loads of over 10 amps connected to 13 amp plugs ?

And how many PAT testing monkeys are going to start “failing” appliances that use more than 10 amps, this year, or 8 amps in a few years time.

And for how long will these reductions in the capacity of so called 13 amp plugs continue ? Down to 5 amps by 2030 perhaps.

I can’t imagine any new domestic washing machines will draw a full 13 amps due partly to legislation.

The manufacturers are going down the route of adding features to machines such as adding a steam cleaning cycle 

It’s all very different to my mothers top loader with a wringer ?

sparkiemike: 

At a recent Elex “seminar” Darren Staniforth from Scolmore made a comment that BS1363 socket outlets were only tested for 8A continuous load. This was news to me because my 1995 version of BS1363-2 says for the Temperature rise test the connected load will be 14A for a minimum continuous period of 4hours or longer until stability is reached and max duration of 8hours. 

 

The 14 amp test load is beyond the rating of the socket, plug and any appliance that should be connected.

So the test covered misuse of the socket by someone using a multiway socket adapter, which is something I see very frequently, but modern adapters are fused so it is a throwback to the nineties, after nearly twenty years there may be an assumption that people have sufficient sockets in their homes, but that is far from true, I regularly see things like the kettle, toaster and microwave all plugged into a single socket using a multiway adapter or the washing machine and dryer.

Having said that how long does it take for a 14 amp load to blow a 13 amp fuse?

Having said that how long does it take for a 14 amp load to blow a 13 amp fuse?

Well, more or less ‘forever’.

Actually a typical 13A fuse will carry 20A for long enough to get the pins hot enough to give you a nasty burn  and to weaken the springs in the holder and the socket. (10^3 seconds is about 15-20mins, and 10^4 seconds is something more like 3 hours… ).  There is no safety value in 13A fuses on a  circuit covered by a16A MCB, and not that much point in 13A fuses supplied by 20A MCBs, as the range of  fault cases where the 13A lets go first is pretty narrow.

The two curves represent  the 'all fire' and the 'never fire' conditions - real fuses have a considerable spread due to wire tolerances and variation in alloy mixture and so forth, and then on top of that the environment, i.e. how well the fuse caps are cooled, has an effect at on the exact boundary shape - if the fuse is running hot, then it  takes less of an overload (time or duration) to melt it.
Actually all fuses and breakers are like this really, just for BS 7671 we are more interested in the 'all fire' condition, and concentrate on that side of the curve, and often assume that the other limit might as well be a single value, the rating on the fuse body, which it isn't.

The unfused adapators are a bit of a throwback - remember these ? ( flameport website) My grand parents place had loads, on circuits protected by 15/20 amp fusewire.