Spur from shower switch

[Jupiter01]

if you meet the requirements of 433.2.2 or 433.3.

Haven't a clue. Sorry!

I was planning to use the same thick (6mm I think) cable between the shower switch and the FCU but a 1.5mm would make my life easier as it will be more flexible to squeeze into these terminals. I'd love to know more on this.

 

[aptsys]

Essentially, if the FCU is less than 3m from the shower switch and risk reduced as far as possible for mechanical damage you're fine.

 

[Jupiter01]

Thanks. The FCU is approximately a metre away from the shower. Based on the above, I will use 1.5mm throughout: between the Shower Switch and FCU and then the same from here on for the lights. I will also need the three core and earth for the extractor.

This will mean that I don't need to purchase 6mm cable for that tony section. Thanks for pointing that out.

 

[EFLImpudence]

Essentially, if the FCU is less than 3m from the shower switch and risk reduced as far as possible for mechanical damage you're fine.

433.3 has nothing to do with it. The cable is protected against overload by the fuse in the FCU. Anyway, this will not happen with one light and one fan.

The 3m. restriction only applies if the cable does not meet fault current requirements.

If this is the case then the cable must be installed in such a manner to reduce the risk of a fault AND the risk of fire to a minimum.
I would think that means installed in metal conduit.

However, I doubt that will be the case.

 

[winston1]

Thanks. The FCU is approximately a metre away from the shower. Based on the above, I will use 1.5mm throughout: between the Shower Switch and FCU and then the same from here on for the lights. I will also need the three core and earth for the extractor.

This will mean that I don't need to purchase 6mm cable for that tony section. Thanks for pointing that out.

You only need 1.0mm cable for lights.

 

[Jupiter01]

I wasn’t planing to use metal trunking. I was going to pass it behind the plasterboard and loop it into the FCU on one end and the shower switch on the other

 

[EFLImpudence]

You don't have to.

I was just explaining the regulation that was quoted which doesn't apply to what you are doing.

 

[Jupiter01]

Sorry, I am slightly unclear.
Can I pass the cable between the shower switch and FCU in the way that I describe above and without using metal trunking but get away with using 1mm cable or does it need to be 6mm cable?

 

[EFLImpudence]

Yes.

 

[Jupiter01]

Sorry to persist, is that a "yes" to using 1mm or 6mm cable in that situation?

 

[EFLImpudence]

Sorry. Yes to 1mm².

 

[Jupiter01]

is 1mm 3 core and earth also adequate for the extractor fan?

 

[EFLImpudence]

Yes.

1mm² is rated at 16A if not covered by any thermal insulation.

 

[Risteard]

You only need 1.0mm cable for lights.

That's only permissible for lightning circuits. A shower circuit is not a lightning circuit.

 

[winston1]

That's only permissible for lightning circuits. A shower circuit is not a lightning circuit.

It connects to lights not a shower.