Spur for washing machine and dishwasher?

[JohnW2]

The inlaws have the WM and dryer plugged into the same double socket and it's been like that for 10+ years. No issues so far, and often used at the same time.

Very many people have similar experiences. However, there are also a good few reports of sockets suffering thermal damage in that situation.

Kind Regards, John

 

[JohnW2]

Also you can fit two fcus if you want, if the machines are hard wired there's no chance of an overload, so as long as your zs is low enough there no problem.

I'm not sure exactly how you were thinking of arranging those FCUs, but as I'm said and implied, to feed two FCUs (or two single sockets) from one unfused spur seems to be generally considered to be "contrary to regulations" (even though there is no such regulation, merely guidance in an 'informative' Appendix to the regs).

Kind Regards, John

 

[chris1982]

But a double socket on a spur off the ring is fine, or not?

 

[JohnD]

tumble driers are particularly troublesome, because they (and immersion heaters) are unusual in drawing maximum current for long interrupted periods. Few other appliances draw maximum load, and those that do (convection heaters, ovens, kettles) draw it either for short periods, or intermittently controlled by a thermostat.

The heater in a washing machine might run for 15 minutes or so (mine does).

A double socket with both of them is about as heavily loaded as you will ever see in an ordinary house. It might be interesting to examine the socket, and the wires behind it.

 

[JohnW2]

But a double socket on a spur off the ring is fine, or not?

It is certainly compliant with the regulations (including 'guidelines'). As you have seen, opinions vary as to how desirable it is to run two 'heavy' appliances off one double socket. Provided that, as in your situation, neither of the appliances is a tumble dryer, I would personally be happy, but (as you've seen) some would probably prefer not to do it even then.

Kind Regards, John

 

[chris1982]

Thanks. So I then could swap the single for a double. But as I wanted to move it by 600mm to the side, there is no way of doing this by adding a length of cable to the existing one? It sounds like I would need to lift the floor boards to get back the ring to run a new longer cable to the new position. That just seems odd to me.

 

[PrenticeBoyofDerry]

I had a client that had two washers (machine and dish) plugged into the same DG socket outlet, this was situated behind the appliances in a kitchen location. Unfortunately this outlet caused a fire. Which was fun!!!! The outlet was part of an RFC, but could not handle the demand of the load.

I would steer away from such a venture, ignore at your peril!!!!

 

[JohnW2]

Thanks. So I then could swap the single for a double.

Yes.

But as I wanted to move it by 600mm to the side, there is no way of doing this by adding a length of cable to the existing one?

Yes, although some people would day that it was 'not ideal' (only because it involves an extra, 'unnecessary', join in the cable) you could do as you suggested in message #15 - i.e. put a connector block and blank plate in the place of the current single socket and run a bit of cable from there to the desired position of the new double socket. I imagine that, since it will not be 'on view', you would probably just run the cable on the surface. However, if you were planning to bury it in the wall, let us know, since there are then some other considerations.

Kind Regards, John

 

[EFLImpudence]

This is silly.

There is no difference whatsoever between one double socket and two single ones on a spur as far as the loading of the cable and electrical usage is concerned.
However, there is a chance that the double socket may be damaged and the single ones won't.

The fact that there is a picture of one in an informative part of the regulations and not the other is irrelevant.

So - which is more sensible?

 

[JohnW2]

This is silly.

I agree - but how many times have you seen people, here and otherwise, being advised (usually by electricians) that they cannot 'spur' a second single socket (or FCU) from a single socket or FCU which is itself an unfused spur?

There is no difference whatsoever between one double socket and two single ones on a spur as far as the loading of the cable and electrical usage is concerned.

Agreed.

However, there is a chance that the double socket may be damaged and the single ones won't.

Agreed.

The fact that there is a picture of one in an informative part of the regulations and not the other is irrelevant.

It's actually more than jiust "a picture of one but not of the other" - there is fairly explicit text ("An unfused spur should feed one single or one double socket-outlet only") - although, as you say, that's only guidance in an 'informative' Appendix of the regs - it is not a regulation.

So - which is more sensible?

That is clear - but, as I said, it seems that, for whatever reason, a substantial, probably high, proportion of electricians seem to continue asserting (without any qualification) that one "must never" spur from an unfused spur, even in the situation we are discussing. What that means, and what it means about how "sensible" they are, I leave you to decide.

Kind Regards, John

 

[EFLImpudence]

"An unfused spur should feed one single or one double socket-outlet only"

That is true - but presumably written by the same person who draw or designed the picture.

Parts of the actual regulations are wrong as well (e.g. bonding to parts that are not extraneous-c-ps and not the part which is).

 

[JohnW2]

That is true - but presumably written by the same person who draw or designed the picture.

Indeed - but my point was that this text indicates that the omission in the drawing of two single sockets on an unfused spur was intentional/deliberate, not just a case of the drawing not covering all possible situations.

Parts of the actual regulations are wrong as well (e.g. bonding to parts that are not extraneous-c-ps and not the part which is).

Indeed so, as we have often discussed. As I've said many times, one can but presume neither the person who wrote it nor the one(s) who (presumably) checked and proof read had even a basic understanding of what equipotential bonding is all about. I will problably raise this issue (and a few others!) during the public consultation on the 18th Ed.

Kind Regards, John

 

[John D v2.0]

According to diversity a double socket is rated at 20a whereas a single could be 13 each. Where the things you're plugging in are predetermined, you're better off with 2 singles. An fcu is a very predetermined load, so you can easily check the ratings

 

[JohnW2]

According to diversity a double socket is rated at 20a ...

I'm not sure exactly what you mean by that. The concept of diversity cannot really be applied to a socket, since the nature of the load(s) determine how much (if any) allowance for diversity is applicable. The (not really correct) view that double sockets are 'rated' at 20A total seems to come from the fact that they are only required to pass the BS1363 temperature-rise test, which is undertaken at 20A (somewhat strangely, 14A + 6A if I recall). A 'famous' (albeit old) statement by MK which I have posted here several times indicates that their double sockets can cope with 19.5A total continuously, but that thermal damage starts happening at (continuous) total currents just slightly above that figure.

... whereas a single could be 13 each.

Indeed - which is why this notion (not mandated by any regulation) that one should not have two single sockets on an unfused spur from a ring final is not only probably unnecessary (nothing to do with any regulation), but actually reduces 'safety'.

Where the things you're plugging in are predetermined, you're better off with 2 singles.

I'm a bit confused by that statement. Do you perhaps mean where they are not predetermined?

Kind Regards, John

 

[John D v2.0]

No, I mean better with two singles than one double.
Because if the total is 20a the sockets going to melt!
But an fcu is even better for each.