extending a fused spur cable

[icewinder]

I have a switched fused spur above the kitchen work surfaces and the fused spur feeds a socket behind the washer, this fused spur and socket are now redundant as the washer is plugged in elsewere. I wanted to add an outdoor socket but wiring directly the new outdoor cable into the fused spur would mean tearing into tiles and worktop splash back which I'm desperately trying to avoid.

Would I be able to use something like a 30a junction box to connect the fused spur cable that originally fed the washer socket with the new outdoor cable leading to the outdoor socket. (it would be tucked safely away behind the units).

The new outdoor socket "might" be housing a cheaper hot tub hence the reason I prefer the new ouutdoor double socket to be hard wired into the fused spur rather than plugging the new outdoor socket in to the old washer socket using a 13a plug.

Also, the outdoor socket is from Screwfix £9.99 (no RCD) so I am wondering, shall I change the fused switched spur for an RCD fused spur ?. It would be easier to see if there's any hot tub problem via indoors than the other side of the garden. Any help would be appreciated

 

[EFLImpudence]

Swap the washer socket for a cooker outlet plate.

Yes you can change the "Fused Connection Unit" (the cable is the "spur") for an RCD one if the circuit is not already covered by an RCD.

 

[ericmark]

In Wales you would need a scheme member electrician to do this work, in England you are allowed to do it, but you still need to follow the current BS7671 regulations for any new work, since you ask about RCD protection I will assume whole house is not already RCD protected, and any RCD needs testing after being fitted, so you should consider if this is really the work you should be doing as DIY.

I would suggest call an local electrician and get a quote, it may not be worth doing DIY, if you do decide to DIY question one is if there is already a RCD in the consumer unit, and if not, then the switched FCU needs changing for a RCD FCU.

 

[Taylortwocities]

Is 13amp enough for your human soup slow cooker?

 

[icewinder]

lol, a friend suggested the best and probably safest way would be to wire it into a fused spur. The plugs does get a tab warm not hot warmish especially when they've been on a good few hours heating up from cold. I was wondering if I could get away with a junction box joining the old socket to the new outdoor cable. Sad thing is, I've no matching tiles

 

[EFLImpudence]

a friend suggested the best and probably safest way would be to wire it into a fused spur.

If you want to use the washer socket then you have no choice but having it limited to 13A.
That's all you can have with a Fused Connection Unit - RCD or not.

The plugs does get a tab warm not hot warmish especially when they've been on a good few hours heating up from cold.

What is the rating of the hot tub? Perhaps it is more than 13A.
Did it come with a plug on it?

I was wondering if I could get away with a junction box joining the old socket to the new outdoor cable. Sad thing is, I've no matching tiles

As above. Use a cooker outlet plate in place of the socket.

 

[icewinder]

In Wales you would need a scheme member electrician to do this work, in England you are allowed to do it, but you still need to follow the current BS7671 regulations for any new work, since you ask about RCD protection I will assume whole house is not already RCD protected, and any RCD needs testing after being fitted, so you should consider if this is really the work you should be doing as DIY.

I would suggest call an local electrician and get a quote, it may not be worth doing DIY, if you do decide to DIY question one is if there is already a RCD in the consumer unit, and if not, then the switched FCU needs changing for a RCD FCU.

The house is protected with a consumer unit. Lay-z-spa suggest the outdoor socket be protected. The pump unit comes with a built in rcd on the cable and a 13a plug. A friend said it would be better if the outdoor socket was connected to it's own fused spur. I would but this would mean ripping into tiles and splash back which I am trying to avoid if possible. I have found an oval 60a junction box, would that work ?. Regarding the RCD fused spur ?, I wondered if this would be better then I can see if the hot tub has any issues tripping in the house etc rather than the on the outdoor socket. And if I use any outdoor gardening items.

I fully understand what you mean about an electrician but if I just plugged an extension in into a weather box with rcd on it I wouldn't need one but we all know that's not the correct way

 

[EFLImpudence]

The house is protected with a consumer unit.

If you say so.

Lay-z-spa suggest the outdoor socket be protected.

By what.

The pump unit comes with a built in rcd on the cable and a 13a plug.

Ok.

A friend said it would be better if the outdoor socket was connected to it's own fused spur. I would but this would mean ripping into tiles and splash back which I am trying to avoid if possible.

I thought you wanted to use the washer socket because it was protected by a Fused Connector Unit and you wouldn't have to do anything to the tiles.
The cable is the spur; if it is protected by a fuse then it is a fused spur.

I have found an oval 60a junction box, would that work ?.

Yes, but swap the washer socket to a cooker outlet plate then you won't need an unnecessary socket nor the junction box.

Regarding the RCD fused spur ?, I wondered if this would be better then I can see if the hot tub has any issues tripping in the house etc rather than the on the outdoor socket. And if I use any outdoor gardening items.

Yes, but it is an RCD Fused Connector Unit. The cable is the spur.

I fully understand what you mean about an electrician but if I just plugged an extension in into a weather box with rcd on it I wouldn't need one but we all know that's not the correct way

So now you are having an RCD FCU, an RCD outside socket and the tub has an RCD itself.
If you have an RCD FCU then an RCD socket is unnecessary.
Nothing against having three RCDs but they might all trip with a fault in the hot tub.


You definitely need an electrician and should not do this yourself.

 

[icewinder]

the house has a comsumer unit, yes I say so

Lay-z-spa website suggest the outdoor socket should have a built in RCD, I didn't write that Bestway did, why ? I will email them and ask why if their units already have one

yes, the pump does have a rcd on the cable

The washer had a double socket at the back of it and is now redundant (washer that use to use it is now re-routed). This washer double socket is fed by a switched fused spur above the work tops. This is not a RCD fused spur I have not changed it, it is a switched fused spur as it stands. A friend suggested that, because the hot tub is abit greedy heating etc that in "his opinion" now I have this fused spur free it might be a good idea to wire the outdoor socket via cable directly into the switched fused spur rather than a 13a plug plugged into the old washer socket. To access the switched fused spur directly would mean hacking into the wall and splash back on the worktops. I am trying not to rip into tiles to connect the outdoor socket so I was asking if it's ok to use a junction box and join the cable that feeds the old washer socket and the new cable that feeds the outdoor socket.

SO if the outdoor socket does not is not a RCD socket would replacing the switched fused spur with a rcd fused spur not protect the outdoor socket say for gardening as well as the hot tub ?


I never said

"So now you are having an RCD FCU, an RCD outside socket and the tub has an RCD itself."

The outdoor socket is not solely for a hot tub it would be used for gardening when needed. I can't help it if the hot tub has an rcd on it so overkill ? like I said I would have to ask bestway why they suggest an rcd outdoor socket. I am not saying 3 rcd's I would like one rcd for outdoor gear whether its indoors or outdoors.

So which is the best option? rcd switched fused spur protecting the outdoor socket
or
rcd outdoor socket ?
I only mentioned the rcd been inside just so I know if the hot tub trips for any reason. I have purchased an outdoor double socket without an RCD but I have one of these spare
https://www.toolstation.com/safetys...cVUJhuON48YivNuA3m2ExWOAPgkl6nMcaAh2hEALw_wcB

I was wondering to take the outdoor socket back and swap for an rcd outdoor socket or save a few bob and if iI can use the rcd fused spur socket.

Hope it all makes sense

 

[ericmark]

A fuse or MCB has a number of values, one is how much power it can switch without damage or flash over, so step one is the measure the loop impedance, so simple maths, loop impedance of 0.23Ω and voltage of 230 = current 1000 amps, most MCB's, RCBO's, RCD's are rated 4.7k amps or over, so that is unlikely to cause a problem. But there is a lower limit. Then there is the current needed to work the device within the required time, so a B32 MCB will trip between 3 and 5 times it's rating with the magnet part of the trip, plus add 5% to allow for volt drop, so 168 amp must flow, so 1.37Ω is upper limit, now a RCD can be affected by strain on the cables, so 6 tests, 2 show it will not trip at 15 mA, 2 show it will trip at 30 mA and 2 show it will trip in 40 mS at 150 mA. We also look at the type of RCD, old ones were type AC where some items today need a type A or better.

Some of this can be verified in seconds, but one does need to be on site to do it, the near enough co ltd is some thing of the past. Your suggestions may work, but "may" is not good enough. Even electricians make errors, I fitted all type AC RCBO's to my house as it said on the packet type B and not curve B. But I don't have a hot tub, so not quite so important.

Just because some people are daft,

does not mean you need to do the same, Darwin effect at getting rid of people who do daft things, is rather extreme. Bet it was not plugged in, just done for the photo.

 

[icewinder]

Thanks for the lengthy informative calc much appreciated it will come in handy today. And do those in the pool (I take it it's not you) know that if you spill your drink in the water it will go cloudy like their brains ?

 

[winston1]

You don’t need a fused spur feeding a single or double socket. The plug you put in it has a fuse.

 

[securespark]

But if you want to connect a external socket to the original WM socket wiring, that would be OK.

The main issue with multiple BS1362 fuses is that often one is not easily accessible.

In your case, there would be one in the fused connection unit above the worktop and one in the plug for the spa which you would plug into the external socket. In the event of a fuse blowing, both would be easy enough to replace.

This is what I would do:

Check the rating plate to make sure the spa's design current does not exceed 13A.
Replace the double socket behind the WM with a cooker outlet plate.
Drill through the back of the cooker outlet plate back box and connect a suitable cable to the external socket.

Replace the fused connection unit with an RCD version (or fit RCD protection to that circuit).

Make sure that all the connections you make are nice and tight. Use pliers to double over the conductors where there is space in the terminals, as this gives more surface area for the screws to contact. This will hopefully eliminate any poor connections.

 

[icewinder]

But if you want to connect a external socket to the original WM socket wiring, that would be OK.

The main issue with multiple BS1362 fuses is that often one is not easily accessible.

In your case, there would be one in the fused connection unit above the worktop and one in the plug for the spa which you would plug into the external socket. In the event of a fuse blowing, both would be easy enough to replace.

This is what I would do:

Check the rating plate to make sure the spa's design current does not exceed 13A.
Replace the double socket behind the WM with a cooker outlet plate.
Drill through the back of the cooker outlet plate back box and connect a suitable cable to the external socket.

Replace the fused connection unit with an RCD version (or fit RCD protection to that circuit).

Make sure that all the connections you make are nice and tight. Use pliers to double over the conductors where there is space in the terminals, as this gives more surface area for the screws to contact. This will hopefully eliminate any poor connections.

The spar does not exceed 13a I've checked and thanks for the advice