Extending a Spur

[steve271]

Hi

I would like to install a new socket to power a Tumble Dryer. It is just on the other side of a plaster board wall from the fridge. I have concrete floors and the only accessible point to take a spur from is the one that powers the fridge. It itself is a fused spur that is protected by a 13 amp fuse (probably should be a 3 or 5 amp!). Could I

• Leave the 13 amp fuse at the wall switch
• Replace the point behind the fridge with a proper socket
• Plug the fridge in and protect it with a smaller fuse
• Extend the radial circuit to power the Tumble Dryer

Would this meet regulations? If the tumble dryer and fridge were on at the same time is the 13 amp fuse likely to blow? I hope I am making sense. I have included pictures below.

Thanks

 

[ericmark]

Since fused technically you can add as many sockets as you like as long as the circuit is RCD protected, so there is no rule which stops you also powering the tumble drier, however a tumble drier is also technically too heavy to be considered as portable unless it has wheels so if over 2 kW the appendix to the regulations suggests it should have a dedicated supply.

I think very few have a dedicated supply to tumble drier, but never the less you should consider if the load for circuit is reasonable. We have no idea what cable or protection devices feed the switch and fuse plate, likely no problem, but can't be 100% sure.

 

[JohnW2]

Since fused technically you can add as many sockets as you like as long as the circuit is RCD protected, so there is no rule which stops you also powering the tumble drier, however a tumble drier is also technically too heavy to be considered as portable unless it has wheels so if over 2 kW the appendix to the regulations suggests it should have a dedicated supply.

The guidance (not 'requirements') of Appendix 15 says nothing about portability (or otherwise), and the "2kW" recommendation only relates to 'cookers, ovens and hobs'. The only other relevant 'recommendation' is that "immersion heaters, comprehensive space heating or loads of a similar profile" should not be supplied by a ring final circuit - but I wouldn't personally say that a tumble dryer qualifies as that. Whatever, as you go on to say, I'm sure that are very high proportion of tumble driers are supplied by a ring final, so that 'recommendation' has clearly fallen on stony ground, even if it was 'intended' to apply to dryers!

I think very few have a dedicated supply to tumble drier, but never the less you should consider if the load for circuit is reasonable. We have no idea what cable or protection devices feed the switch and fuse plate, likely no problem, but can't be 100% sure.

Agreed. As you have said, provided the dryer is no more than about 2kW, there should be no problem is running both it and a fridge from the same fused spur - but, as you also say, one would need to be sure that the circuit is RCD protected before adding a socket. There's no issue regarding the cable - since no credible (or compliant) cable would be unable to cope with 13A (i.e. 1.5mm² would theoretically nearly always be adequate).

Kind Regards, John

 

[steve271]

Hi, thank you both for that information and advice. There is a dedicated ring for upstairs sockets, downstairs sockets and kitchen sockets. All are rcd protected. Can I assume that it would be 2.5mm2 that connects the fridge point as they put a 13amp fuse in. Sorry for my ignorance!

 

[JohnW2]

Hi, thank you both for that information and advice. There is a dedicated ring for upstairs sockets, downstairs sockets and kitchen sockets. All are rcd protected. Can I assume that it would be 2.5mm2 that connects the fridge point as they put a 13amp fuse in. Sorry for my ignorance!

Yes, it will almost certainly be 2.5mm² - although, as I said, even 1.5mm² (the smallest cable allowed for a non-lighting circuit) would probably be adequate for 13A.

Kind Regards, John

 

[steve271]

Thanks. The connected load for the dryer is 2600w. Should this be ok along with the fridge.

 

[JohnW2]

Thanks. The connected load for the dryer is 2600w. Should this be ok along with the fridge.

Probbaly just about, particularly given that it will not be drawing power for long continuous periods. Do you know what the fridge says it needs, electricity-wise?

Kind Regards, John

 

[steve271]

Hi John, thanks, it says 80w fused 13A

 

[JohnW2]

Hi John, thanks, it says 80w fused 13A

That sounds OK then.

Kind Regards, John

 

[steve271]

That sounds OK then.

Kind Regards, John

Thank you very much for your help.

Kind regards

Steven

 

[steve271]

One final question. Could the start up current of the fridge compressor blow the fuse if it happened to kick in as the tumble dryer is starting?

Thanks

Steven

 

[echoes]

I owned a house several years ago where a fridge and tumble dryer were supplied by the same 13A fuse.
That fuse blew regularly when the dryer was on, presumably when the fridge compressor started up.

 

[steve271]

I owned a house several years ago where a fridge and tumble dryer were supplied by the same 13A fuse.
That fuse blew regularly when the dryer was on, presumably when the fridge compressor started up.

Thanks for that info. That would be very annoying. I might end up having to tap into the ring main somewhere or just bite the bullet and get a professional in.

 

[JohnW2]

One final question. Could the start up current of the fridge compressor blow the fuse if it happened to kick in as the tumble dryer is starting?

I suppose it's not impossible that could happen if compressor and dryer motor started absolutely simultaneously but, despite echoes' experience, I would have thought it extremely unlikely.

It takes at least around 22A to blow a 13A plug/FCU fuse ever, and a lot more current than that that to blow the fuse very quickly (i.e. if the excessive current is very brief, as with a start-up current). The running current of your fridge is only a bit over 0.3A, so even if the start-up current of the compression were (for a second or two) 20 times that (which I imagine is unlikely), that would not be much over 6A or so.

The dryer's start-up current is more difficult to estimate, since the great majority of the 2600W is the heater, rather than the motor. However, I would have thought that if dryer+fridge was likely to blow a fuse if they both 'started up' simultaneously, it would not be uncommon for a dryer alone to do it - and that's not something we hear of happening.

If it were me, I wouldn't be at all concerned, but it's obviously your choice/decision. Looked at pragmatically, if I'm wrong not to worry, it would only happen once (since I/you would then realise the need to change the electrical supply arrangements) - so, although annoying, would not be the end of the world.

Kind Regards, John

 

[EFLImpudence]

It's also worth noting, with reference to a recent thread regarding spurs, that had the OP had a double socket (and drier in the same room) we would have heard nothing about it - yet, electrically, everything would be exactly the same as he wants to do.