dont need switched live in 3 core and earth cable

[pirate78]

Hi

I am replacing a broken low voltage shower fan with timer. The existing setup has a 3 core and earth cable running from the transformer to the fan unit which has the timer circuitry. I have bought a replacement fan and transformer thinking that it would be a like for like replacement. However the replacement has the timer circuitry located with the transformer and not the fan. So the transformer input has 3 core cable going in but only 2 wires as output.

My question is can I re use the existing 3 core and earth cable connecting the new transformer to the new fan ? So I just use the live and neutral wires in the cable and leave the switched live unconnected at both ends (and probably taped). I would replace the 3 core with 2 core but it is going to be difficult to do this.

Thanks

 

[RF Lighting]

It's fine to reuse the 3 core. Just terminate the unused wires in a piece of strip connector. No need to tape them.

 

[mikeyd]

I'm sure I read years ago (probably 16th edition regs) that any unused cores should be connected (at least at one end) to a CPC (earth) and sleeved as such at both ends. I remember at the time thinking it made sense. If it's there, make use of it.

 

[RF Lighting]

There is no CPC in an SELV circuit, and introducing an LV potential into the area is a bad idea.

 

[Risteard]

So I just use the live (sic) and neutral wires

There is no neutral on the SELV side as neither conductor is referenced to Earth.