Any concerns about outside wiring?

[jamie Smith]

Afternoon all

I have 3 double external sockets (one of which is in my shed) at my house and wanted to make sure they are set up correctly, being as I don’t know who did them.

I have a separate ring on my consumer unit for the kitchen sockets, of which there are four. Only one of those is in constant use for the fridge, the others are for the kettle etc. There’s a spur from one of these sockets and runs into a 13A fused spur on the kitchen wall. From here, there’s an armoured cable that goes through and then down the external wall, before running through a conduit along the garden to power the first socket. From here, there’s another spur to the next socket and a final one to the shed (for the tumble dryer), making 3 outdoor sockets in total with quite long cable runs in between.

The job was done 8 years ago when the house was re-wired apparently and all of the wiring and fittings appear to be top quality weatherproof. Need I be concerned about anything, or should I plug in my flymo and away to go?

 

[davelx]

The most important thing is to check that the sockets are protected by an RCD or RCBO - probably in the consumer unit. If you are not sure how to tell and can post a piccy showing the CU and details of the breakers, we can help.

 

[jamie Smith]

OK. As I understand, the kitchen sockets (from which the external sockets are powered) have their own labelled RCD (is this the thing with the trip switch on it?) on the consumer unit, because I can isolate them and they turn off the outside sockets as well.

Furthermore, the 'fused spur' I mentioned is actually, I am reliably informed, a Powerbreaker RDC FCU which is fused at 13A. The nearest thing I can find to it on screwfix is as follows:

http://www.screwfix.com/app/sfd/cat/pro.jsp?cId=A231858&ts=28891&id=14770#

 

[Lectrician]

They sound like they are RCD protected which is fine.

What length of run are we talking here? Is there any more load other than the tumble tryer? The tumble drier will eat the majority of the available capacity of your ciruit!

 

[jamie Smith]

Hmmm, therein lies the problem I think. The initial run is 10m, then about 7 metres to the next socket, then a whole 20m to the shed.

I have never run the tumble and used the other sockets at the same time, what do you think would happen if I did and is there something I can do to enhance the capacity?

 

[Spark123]

What size is the armoured cable?
Just to give you an idea to uprate the supply will probably involve replacing the cable with a larger one run directly from your CU to a new CU in the shed.

 

[Lectrician]

I am assuming it is 2.5mm SWA.

The RCD FCU at the origin will have a 13amp fuse. The tumble drier will have a loading of around 10-13amps (can you tell us the kW of the dryer - look for a rating plate). This is basically all you should use on this circuit at any one time. Any more than this will blow the 13amp fuse. The 13amp fuse will run higher than 13amp for a little while.

A 37m run of cable with a 13amp load will drop around 7.5volts. You may drop a maximum of 9.2volts. The ring circuit will already have dropped some volts. You are right on the edge as far as volt drop go's.

 

[jamie Smith]

Thanks. I suspected that might be the case and it has worried me from a safety point of view too. A trainee spark friend of mine suggested some other options:

1. I have a redundant 30 amp shower supply with its own RCD on the CU, which he reckons can be spurred down to use as an alternative supply

2. I can replace the cable with a heavier one, as you suggested

3. I can get rid of the last 20m run and instead run the tumble from an extension lead and prop the door shut with a paint opt

If I have a seperate CU, would this still have the same voltage drop problem?

 

[Lectrician]

Larger cable sorts volt drop.

30amp feed would need larger cable again, and larger still possibly for volt drop.

You say your shower has it's own RCD? Is it an RCD or MCB?

The max volt drop is what we are allowed to drop in an installation - in reality you will most likely find it is ok as the voltage entering the installation is likely to be higher than the lowest specified limit for the supplier anyway.

Depends what else you are likely to use, how much you want more lecky etc etc.

 

[Spark123]

Without being there to evaluate the situation it is pretty difficult, you could leave the 2 garden sockets on the RCD fused spur from the ring circuit and disconnect the shed. Install a fresh supply to the shed from the CU.
Before you do anything though, it is advisable to have a professional to come and have a look and give advice. Most of this work is notifiable to your LABC under Part P of the building regs in England/Wales.

 

[Lectrician]

Put the tumble drier in the house, and use the sockets for little else!

Doesn't your missus get peed off taking a basket of washing 40m up the garden to a shed from the washer in the house? Don't tell us the washer is up there aswell!







On a side note - I had to run a supply out to a garage once for a washer and dryer, so ran a 30amp circuit - house owner (was actually a builder type....labourer probably!) had dug trench, and was running a cold water supply up aswell.

Didn't think of the waste did he!

I am not kidding when I say he had the outlet of the washer hooked to an old water butt, and pumped the water to the nearest CIVIL drain in the garage block every so often!

 

[jamie Smith]

I can't believe the guy with the washing machine, that's priceless. The irony of my situation is that the shed is only 10 feet away from the house, but the way the circuit is wired is up the garden, across and then all the way up past the original starting point and into the shed...like a big horseshoe.

Either way, i've called the professionals in as i'm out of my depth. The spark said he'll run a new supply from the CU to the shed, which, like you, he said is the safest and most direct way of getting the job done.

Thanks for all the advice, it certainly helped me to speak to the spark with at least some prior knowledge of the subject.

 

[jamie Smith]

Just another quick question while we’re on the subject….I got talking to nextdoor neighbour this morning about his external wiring. He’s got a spur from inside his kitchen – where he’s then got an 13 amp RCD FCU - and he’s got about 12m of SWA clipped along the top of his fence, which then drops down the fence post to his socket, from which he runs 2 lights, which are each about 5m away from the socket. The socket is pretty heavy duty with it’s own RCD protection and it’s been there for years. Need he worry about anything?

 

[Lectrician]

Na - his sounds fint to me.

 

[sm1thson]

...and he’s got about 12m of SWA clipped along the top of his fence...... Need he worry about anything?

wind?