Cavity wall.

[Rob.quick]

I need to extend a cable that runs inside the cavity wall of my house, am I legally able to do this? And if so what connection type would you use? The ideal solution would be to replace the cable however, this is not possible due to the location. The cable is for an external security light running at 0.5A.

Many thanks.

 

[telectrix]

depends o wher you are going to put the join. a junction box with screw terminals has to be accessible. the best way to join a cable is with crimps and then heat shrink sleeving if they are going to be inaccessible after.

 

[RWJ]

cable that runs inside the cavity wall

Is it an external cavity wall / internal partition wall / cable in conduit?

 

[Rob.quick]

External cavity wall.

The cable will not be accessible after the wall has been rendered, when you say 'crimps' do you mean car type ones that you can buy from an auto parts shop? Is this method safe and legal, I'm not questioning you, just want to make sure the solution is durable long term?

Thanks

 

[ipf]

230v rated, correct size for cable, with ratchet crimping tool. Preferably, get someone qualified.

 

[telectrix]

External cavity wall.

The cable will not be accessible after the wall has been rendered, when you say 'crimps' do you mean car type ones that you can buy from an auto parts shop? Is this method safe and legal, I'm not questioning you, just want to make sure the solution is durable long term?

Thanks

those car type ones, if you mean SCOTCH LOCKS , ARE A DEFINITE NO NO. google in line insulated crimps/ratchet crimpers.

 

[Marvo]

Agreed, never use anything electrical from a car shop to repair household electrics. Take a swing past an electrical wholesaler to get the items you need.

The problem is by the time you've bought the crimpers you might find it's cheaper just to get an eletrician around for half an hour to do the job properly. That way you also get piece of mind knowing you won't need to chisel the wall open again in six months time.

 

[Rob.quick]

The cable currently sits within the cavity void, I could run the current cable back into the house via the inner brick work, terminate under the floor boards with a junction box that would be accessible and then feed the cable straight back through the cavity and out onto the external wall. Would this be a better option ?

 

[telectrix]

sounds better. but how will the junction box be accessible under the floor and carpet. a maintenance free JB would be a good idea. a qualifeid electrician would be even better. for the sake of £40-£50.

 

[Marvo]

Sounds promising if the connection will be accessible.

 

[Rob.quick]

Telectrix, I appreciate the feedback and if I'm honest I probably will get a electrician to do the job however, I'm always interested to understand the 'right' way of doing things.
The junction box wouldn't be 'stand alone' however, would be easy to access by lifting the boards. Would the concept of having cables going from the cavity then internal then external be deemed as 'correct'?

Thanks

 

[Marvo]

In the UK there are safe zones that must be complied with when running cables. That's as far as I can tell you, I work to a different set of regs.

 

[D80]

Any insulation in the cavity of the wall?

 

[Rob.quick]

Yes, insulated walls. The cable is for a security light running at 0.4A.

 

[telectrix]

some of the older wall insulation attacks the pvc of cables. apart from that, as long as the cable is not prone to damage from chafing, should be OK. however, i would drill from by the JB straight through the wall and then run surface outside in black flex.

 

[D80]

What kind of insulation?

 

[Rob.quick]

Rock wool I think it's called

 

[telectrix]

that's not a problem then. cable won't overheat as the current is well below it's capacity, even in insulation.

 

[D80]

some of the older wall insulation attacks the pvc of cables. apart from that, as long as the cable is not prone to damage from chafing, should be OK. however, i would drill from by the JB straight through the wall and then run surface outside in black flex.

Seen it a few times where the polystyrene wall insulation has taken off all the PVC cable insulation. No problem until the cable is moved at all.