Wiring an extractor fan with the shower unit

[SheCrow]

I have recently had an extractor fan put in the bathroom, with an over-run in place of an old one. The old one was wired with the shower to come on when the shower was activated. I am told this is against regulations and it could possibly cause a fire. As I did not want to have the light come on each time I had a shower, the electrician put in a separate switch for the fan in the airing cupboard next to bathroom. This I switch on when I have a shower, switch off when I'm finished and it runs a further five minutes. No hardship.
I am told by my husband that this is rubbish and it could have been wired in with the shower switch. I go with the electrician. Can anyone enlighten me?

 

[ban-all-sheds]

What you were told may have been true, it depends what sort of shower it is, and how it was done. If it's an instant shower then it was almost certainly true, as it was most unlikely to have been done properly.

With an instant shower what your husband wants can be done, but it would need a contactor, either energised via the lighting circuit to switch the shower supply, or energised via the shower supply to switch the lighting circuit supply to the fan. Or you could use a flowswitch in the water supply to the shower.

Just wiring the fan directly off the shower circuit is dangerous as the cable won't be anywhere near large enough to be on the size of fuse/MCB used for the shower, and if anything had gone wrong there could indeed have been a fire.

 

[plugwash]

Just wiring the fan directly off the shower circuit is dangerous as the cable won't be anywhere near large enough to be on the size of fuse/MCB used for the shower, and if anything had gone wrong there could indeed have been a fire.

Further showers usually have a DP switch to isolate all poles but this isolation will be broken by connecting a fan that needs both a permanent live and a switched live.