Installing extra appliance, electric supply advice needed

[Smiffy7]

Hi, yes what you suggest is fine. My mothers house which was built in 1999 has exactly what you have the only difference is she has 20a DP switches instead of FCU's. When she moved out of the house we discovered that the DW and WM where plugged into the single socket with a 4 way extension lead under the plinth ! It worked for years with no problems.

If you washing machine has a hot water intake that's even less likely to be on a boil wash !

My original suggestion was a 32a switch which will give you plenty of connection space and a good quality one has 2 sets of screw terminals.

I stay clear of the cheaper Con-verta sockets and buy a 1gang to 2 gang conversion box and use an MK or Crabtree socket.

This is a tile save solution. The only other option is an additional socket supplied from below


Regards,

DS

Presumably the solution we are now discussing must rely on each appliance therefore having a 13A fused plug, particularly as we are getting rid of the FCU? Would you mind linking me to your recommended switch and socket please so I know I'm getting the right thing?

I see you can also get DP FCUs - would I be right in saying that the only difference between that and a DP switch is the fuse, otherwise they are doing exactly the same job?

My washing machine does not have a hot water feed by the way...

 

[JohnW2]

I see you can also get DP FCUs - would I be right in saying that the only difference between that and a DP switch is the fuse, otherwise they are doing exactly the same job?

As far as I am aware, all, or virtually all FCUs now available have DP switches - so, yes the main difference is the fuse. However, since the fuse in an FCU cannot be greater than 13A, it's possible that the switch in an FCU is not designed/rated for more than 13A.

Kind Regards, John

 

[Smiffy7]

Thanks for the clarification John.

I just wanted to end the thread by confirming what I'm doing/buying (now bought)....

So I'm swapping my 13A FCU with one of these http://www.discount-electrical.com/...us-32a-double-pole-switch-with-neon-p245/s263

I'm swapping the single un-switched socket below the counter with this http://www.ebay.co.uk/itm/1-TO-2-GA...ON-/350561955922?ssPageName=ADME:L:OC:GB:3160 and one of these http://www.discount-electrical.com/...logic-plus-twin-13a-switched-socket-p232/s250. I went for a switched double socket a) because it was half the price of an un-switched double and b) I thought it would be useful to be able to isolate one appliance while still use the other?

I am hoping this is all very easy, straight swapping with just some re-wiring of the existing 2.5mm T&E cables. I might allow to replace the spur cable down the the socket if I need a bit more length at the bottom.

I wanted to keep the socket below the counter as flush as possible to maximise space, and a 16mm converter box was the slimmest I could find. Is there any other slimmer solution out there that I may have missed?

Last question - so by all accounts this solution will be perfectly safe electrically speaking, although my understanding is that it is debatable as to whether it is strictly regs compliant - is my understanding correct?

Thank for all the help; great forum!

 

[JohnW2]

I'm swapping the single un-switched socket below the counter with this ... I went for a switched double socket a) because it was half the price of an un-switched double and b) I thought it would be useful to be able to isolate one appliance while still use the other?

Well, no-one can argue with the price advantage but, as for your (b),once you have got access to the socket (to switch off one of the appliances), you could pull the plug out - which gives pretty good isolation!

Last question - so by all accounts this solution will be perfectly safe electrically speaking, although my understanding is that it is debatable as to whether it is strictly regs compliant - is my understanding correct?

I don't think that anyone would/could suggest that a 2.5mm² unfused spur supply just one double socket was not compliant with regulations. Where there is some 'debate' relates to how 'wise' it is to have two 'large' kitchen appliances run off the same double socket - as you have seen, opinions vary, but, again, I don't think that it could be suggested that it is non-compliant with regs.

The only debate about regulatory compliance would arise if you wanted to have two single sockets (rather than one double) as a 4mm² unfused spur - electrically probably 'better' (certainly not 'worse' or less safe), but with varying opinions regarding regulatory compliance!

Kind Regards, John

 

[deadshort]

The regulations permit 1 twin socket wired with 2.5mm cable as an unfused spur from a ring circuit. Yes or no ?

That would be a regulation ? yes or no ?


Regards,

DS


ye, ye.

 

[EFLImpudence]

As you wrote it - yes but...

which regulation did you have in mind?

 

[deadshort]

Well you tell me ?

DS

 

[EFLImpudence]

Well, as you wrote it - Ring > 2.5mm² unfused spur > one twin socket is stated in Appendix 15 which is only informative.

Even if you take that as a regulation, what if you increase the csa of the spur and fit two single sockets?
No additional usage possible. Safer regarding socket use.

Because that is not illustrated in Appendix 15, does that mean it is forbidden?

 

[deadshort]

Sorry, If you are going to quote me please, get it right.


Much appreciated.

Regards,

DS

 

[EFLImpudence]

What does that mean?

 

[ban-all-sheds]

I'm confused.

Partly because I haven't been following the last 5 pages all that closely, but partly because of the cryptic posts from DS.

Here's the deal.

Ring finals are not compulsory - nobody has to have them.

But if you do, then you have to put up with the restrictions which stem from them being, fundamentally, a deeply flawed design which no sane person would have allowed if starting with a clean sheet of paper and an eye on proper circuit design. They were, and remain, a kludge, no doubt well intentioned at the time, but nevertheless a kludge. The IEE/IET have had to twist and compromise the regulations over the years to try and keep them "compliant". If they are such a good idea, how come nobody else has them except us, and a few odd spots around the globe which used to be under our influence?

As I said, you don't have to have them. If you don't want to have to deal with the restrictions on spurs, then don't have them - put in radial circuits which throughout their length comply unambiguously with Ib ≤ In ≤ Iz and get on and enjoy the freedom to branch off wherever you like, as often as you like, and to serve as many sockets as you like. It really is that simple.

OR - stick with ring finals, and accept the limitations on spurs which come with that. That also really is that simple.

 

[JohnW2]

OR - stick with ring finals, and accept the limitations on spurs which come with that. That also really is that simple.

I do have a lot of sympathy with EFLI's view which started all this, and feel that it's not unreasonable to apply electrical common sense in interpreting what the regs say (which is virtually nothing - what little there is exists in App 15) about unfused spurs from ring finals ...

As we know, there is nothing in the regs which prohibits two spurs originating at the same point in a ring and, particularly if one is not close to the end of a ring, there is absolutely no electrical reason why that should not be done. Hence, give or take the issue of the cable capacity of socket terminals (and, if you wanted to invoke that argument, we could talk about spurs originating from a 'large' JB!), there is no regulatory reason why two 2.5mm² unfused spurs, each supplying one single (or, indeed, double) socket should not originate from a single point on the ring. If one accepts that (electrically), then there is, AFAICS, no electrical reason why a single 4mm² unfused spur could not supply two single sockets (or, indeed, if it was far enough from the end of the ring for overload of the ring cable to be impossible, an unlimited number of sockets!).

Kind Regards, John

 

[Smiffy7]

I'm loving the debate

For piece of mind, could I just get the support from 1 or more electrically minded people that the following arrangement will not burn my house down:

32A DP switch located on the ring final > 2.5mm unfused spur > double socket supplying a washing machine and dishwasher

Will it be prudent / wiser / safer to upgrade the spur to 4mm as I keep hearing people mentioning?

Thanks

 

[ban-all-sheds]

A double socket only has to be able to cope with a total of 20A. Not necessarily enough to run both a tumble drier and a washing machine.

 

[JohnW2]

I'm loving the debate For piece of mind, could I just get the support from 1 or more electrically minded people that the following arrangement will not burn my house down: ... 32A DP switch located on the ring final > 2.5mm unfused spur > double socket supplying a washing machine and dishwasher ... Will it be prudent / wiser / safer to upgrade the spur to 4mm as I keep hearing people mentioning?

The suggestion about 4mm² is not really anything to do with "prudent / wiser / safer" but was an attempt to address the guidance in the regulations (which some would say was 'silly') which says that a 2.5mm² unfused spur may supply one double socket, but not two single sockets

If there is an issue, as BAS said, it is whether (regardless of cable size) it is wise to have one double socket supplying both a WM and dishwasher - and, as you will have seen, opinions about that vary.

Kind Regards, John