Routing of electrical through an existing stud wall

[00db]

I am redoing my bathroom that currently has the shower electrical feed routing up through the floor boards, loose along the underside of the bath and into the loft through the waste pipe boxing. As this also houses the hot water feed from the boiler in the loft I don't think its the best solution!

The stud wall at one end of the bathroom is of the type that has cardboard lattice work internally. I have managed to punch a channel all the way from top to bottom using some drain rods. The channel is within the 150mm Safe Zone of the corner wall.

My question is, do I need to install conduit to run the cable through or can I just feed it through the hole I have created?

 

[EFLImpudence]

Conduit will reduce the Current Carrying Capacity of the cable, so it depends.
Conduit is not necessary but the structure of the wall is not good for dissipating heat, so again it depends.

You must have RCD protecting the circuit if you go ahead.

If there is no RCD then leave the cable where it is.

This will be notifiable work if you class it as a new circuit in the bathroom.

Just seems like it is unnecessary work.

 

[ban-all-sheds]

What size is the cable and what rating is the shower and the MCB?

Did you consider the effect that burying the cable will have on its current carrying capacity?

Is the circuit on an RCD?

 

[ban-all-sheds]

Doh!

 

[00db]

I have not considered the current carrying capacity.

The shower is an 8.5kW

MCB is 63A with 30ma RCD

Cable is 6.0mm.

 

[00db]

Only reason I am considering it is because the electrics in the house were pretty dodgy when I bought the place. Cables pushed into the joist notches against CH Pipes ( they had started to melt).

Unless I rip down the boxing around the waste pipe I have no way of knowing if the shower cable is completely clear of the hot water pipe.

 

[ban-all-sheds]

I have not considered the current carrying capacity.

You need to.

And ambient temperature if it's boxed in with hot water pipes.

The shower is an 8.5kW

MCB is 63A with 30ma RCD

Cable is 6.0mm.

6mm² cable is not OK on a 63A breaker no matter how it's installed, and when buried in that wall may well not be OK for the load of the shower.

You need to do more than just re-route the cable, and I'm afraid it's now become notifiable.

 

[00db]

time to call in the electrician then!

thanks for the guidance

 

[ban-all-sheds]

Only reason I am considering it is because the electrics in the house were pretty dodgy when I bought the place.

And now you've found more dodginess - 6mm² cable on a 63A breaker. Were you aware that that was a problem?

If not, what else might be wrong that you've not recognised?

Cables pushed into the joist notches against CH Pipes ( they had started to melt).

Not only should they not have been touching the pipes they should never have been installed in notches in the first place.

Unless I rip down the boxing around the waste pipe I have no way of knowing if the shower cable is completely clear of the hot water pipe.

You need to know.

Actually - what you need to do is to get an electrician to do a thorough investigation of the entire installation.

 

[00db]

to be honest I didn't think about it until you said it was a problem. from a bit of research max amperage of 6mm cable is 40A?

The Consumer Unit is pretty old, im gonna get an electrician in to replace it as that way i should get a full audit /certification done on the wiring.

cheers for the guidance

 

[riveralt]

MCB is 63A with 30ma RCD

Are you actually talking about a Main switch 63Amp 30mA RCD combined
like this?

http://www.tlc-direct.co.uk/Product...w=63+amp+RCD&gclid=CJLA9MKPlq0CFZMhtAodWC3Vug
Reason I raise it is that it is unusual to have a 63Amp MCB fitted in a domestic enviroment.

 

[00db]

as the CU had run out of spare MCBs a previous electrician had added a separate unit along side the CU. One MCB rated to 63A and a 30ma RCD next to it ( from what I can tell)

not entirely sure what im looking at. getting a sparky in anyways.

 

[chivers67]

as the CU had run out of spare MCBs a previous electrician had added a separate unit along side the CU. One MCB rated to 63A and a 30ma RCD next to it ( from what I can tell)

not entirely sure what im looking at. getting a sparky in anyways.

http://www.tlc-direct.co.uk/Products/CPSP2.html Does it look like this?

 

[00db]

Yes it is one of those in the link

 

[riveralt]

Yes it is one of those in the link

So you have a small consumer unit with a combined 63Amp 30mA RCD main switch.
What is the size of the MCB?
If it is 40Amp then 6mm2 T&E (ccc 46Amps - clipped direct) should be okay for an 8.5kw (37 Amp) shower provided there are no insulation issues and I would avoid conduit this is likely to reduct the ccc to 38Amps .