Extractor fan from shower isolator

[nicebutdim]

Just realised my post said 'would' instead of wouldnt! To clarify, I WOULDN'T recommend people operate the shower isolator after every shower.

I'm fastidious about isolating appliances that aren't in use (don't ask why), but surely shower isolators should be able to handle regular use provided they aren't being switched under load?

 

[DPG]

I'm fastidious about isolating appliances that aren't in use (don't ask why), but surely shower isolators should be able to handle regular use provided they aren't being switched under load?

They absolutely should yes. But I still would prefer to not use one multiple times every day of the year.

 

[Paulconlon]

I came across this today when changing a shower isolator that was stuck in the on postition.

40A Hager RCBO feeding 10mm² twin + earth to a pull cord shower isolator. On the load side of the isolator there was 10mm² going off to the shower as you would expect, but also from the isolator was 2.5mm² T+E feeding a 3A fused spur in the loft, which then fed an extractor via 1.5mm² T+E.

So the extractor is switched on and off with the isolator, along with power to the shower. Not very good practice IMO, but is it compliant?

I believe so: the 2.5mm² and 1.5mm² T+E should be protected from overload by the 3A fuse. PFC was about 1100A, so the requirements of the adiabatic equation should be met. RCD protection means disconnection times are met.

What do you guys and girls think?

I would personally never bounce on a feed from a switched supply but suppose you would always want the fan on when showering so not the end of the world.

 

[nicebutdim]

They absolutely should yes. But I still would prefer to not use one multiple times every day of the year.

I had one fail that was never switched under load. Always assumed it was poorly terminated, but suppose it could equally have been a poor quality switch.


Edit: Memory is warming up and I remember the fishy smell and badly burnt terminal which pointed toward poor termination.

 

[Pretty Mouth]

Thanks for all your comments.

Just looking at table 537.4 of the BBB. BS 60669-1 are suitable for functional switching, but not for isolation? I must have got that wrong, what is the correct BS for pull cord shower isolators?

I guess if I were to suggest a non compliance, it might be 463.1.1

Functional switching shall be provided for each part of a circuit which may require to be controlled independently of other parts of the installation.
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I'll suggest to them that I move the extractor over to the lighting circuit, perhaps with its own pull cord switch if that's what they're into. But not particularly worried if they say no, I'm happy that it's not dangerous.

 

[LastManOnline]

It will have a lot of wear and tear with daily use. And some fan isolators aren't the most reliable of things at the best of times. I would normally recommend people isolate the shower every time they have used it. Also the fan could do with leaving on for a few minutes after the shower has been used,

No the cable must be able to withstand fault current.

Why have, nt the previous posts disagreed with your assessment?

 

[DPG]

Why have, nt the previous posts disagreed with your assessment?

Yes, that's the one with typo in. Autocorrect at its worst!

 

[telectrix]

my preference is a timer fan with an independent switch, not controlled by the light switch. then customer can have light only, fan only, or both. ssimples.

 

[LastManOnline]

Yes, that's the one with typo in. Autocorrect at its worst!

Hi DPG. No issue with your assessment. It was westwords comment I was referring to. He raised a point about fault current that no one responded to