Bathroom fans mountain out of molehill?

Getting a sparky to install an inline fan for our ensuite, given it's next to the bed we want either a pull switch only arrangement or a timer but with a pull switch we can use to switch off at night. No RCD on light circuit. Isolator apparently has to go in loft. Now I expected the pull switch to be on the live feed to achieve what we want. But I was told that if the switch was on and the light triggered the timer, it would run on for the time even if we pulled the cord after . I suggested a double pole switch but apparently that would be rather bulky and 45amp. Now he's found a new pull cord triple pole isolator which I guess is fine, but apparently we still need an isolator in the loft to comply with regs

Make sense?

Additionally,we recently had the main bathroom refurbished and the guys put an axial fan in the ceiling, which the new guy says he can't do because of regs and no RCD. The guys got a subbie to install the axial, isolator in loft and triggered by light or humidistat.

rjm2k said:

... we want either a pull switch only arrangement or a timer but with a pull switch we can use to switch off at night. No RCD on light circuit. Isolator apparently has to go in loft. Now I expected the pull switch to be on the live feed to achieve what we want. But I was told that if the switch was on and the light triggered the timer, it would run on for the time even if we pulled the cord after . ... Make sense?

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No, that makes no sense. If it is a timer fan, then interrupting the 'permanent live' feed to it with a single-pole pull-switch would preventing it coming on or running on, even if its switched live was receiving electricity from the light.

rjm2k said:

Additionally,we recently had the main bathroom refurbished and the guys put an axial fan in the ceiling, which the new guy says he can't do because of regs and no RCD. The guys got a subbie to install the axial, isolator in loft and triggered by light or humidistat.

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Current regs do, indeed, require any circuit supplying a bathroom to be RCD protected.

Kind Regards, John

rjm2k said:

No RCD on light circuit.

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RCDs required for pretty much everything now.

rjm2k said:

want either a pull switch

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What's wrong with a switch in the wall?

rjm2k said:

Isolator apparently has to go in loft.

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Isolator can go wherever is convenient. Assuming you even have one.

rjm2k said:

I suggested a double pole switch but apparently that would be rather bulky and 45amp

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Nonsense, DP switches available in many sizes, and that also assumes you actually need a DP switch.

rjm2k said:

but apparently we still need an isolator in the loft to comply with regs

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Ask them to show you which regulation that is.

If you want separate control of the fan, a double gang switch in the wall would be the simplest solution - one switch for the fan, one for the light. Timer optional. Isolator in the loft next to the fan if desired for maintenance.
Connecting to the light is fairly common, but is not required and certainly not the only option.
Humidistats are generally a fail and should be avoided. Use of those generally results in the fan never working, or running permanently.
The lack of RCD is fixed by installing an RCD.
Axial fans are generally useless and don't work well with any length of ducting. Centrifugal or mixed flow types are far better.
The final item is that with a decent fan in the loft, the amount of noise in the room below should be next to nothing.

Thanks,that's what I thought . He's pretty insistent so I'll let him put the extra pull cord isolator on as no harm in doing so. Is there really a need for one in the loft too? Again no harm but seems pointless with the pull triple isolator in the room

Flameport

Room is tiled so less damage putting switch in ceiling, light switch is also a pull so made sense to tuck a new one for fan away in corner.

As for the axial humidistat it seems to work quite well, at least at the moment but only a few months in and a short run on ducting

rjm2k said:

Thanks,that's what I thought . He's pretty insistent so I'll let him put the extra pull cord isolator on as no harm in doing so. Is there really a need for one in the loft too? Again no harm but seems pointless with the pull triple isolator in the room

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Agreed, on both counts - no point, but no harm.

If it were me, I would, however, probably be wondering about the wisdom of employing someone who was being 'insistent' about something that was not actually necessary, since it would leave me wondering what other deficiencies there might be in his knowledge/understanding!

Kind Regards, John

rjm2k said:

He's pretty insistent

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He is someone too ignorant to be doing the job, that's what he is.

Fingers crossed that there's nothing else he doesn't know or understand, eh?

Doh!

There is no requirement for the fan to be switched by the lights, so it would need a passive RCD which would also isolate likely a FCU RCD and a switch, simple. I seem to remember in one of the early Part L documents it actually said it needed to be so it could work without the lights, but that requirement has now gone.

ericmark said:

There is no requirement for the fan to be switched by the lights, so it would need a passive RCD which would also isolate likely a FCU RCD and a switch...

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I think there could perhaps be some debate as to whether an RCD FCU (for the NEW fan) would be compliant with regs.

Current regulations require that any circuit supplying a bathroom be RCD protected. Although that reg is not retrospective, it could be argued that extending a bathroom circuit (to include a new fan) would be enough to invoke the requirement for the whole circuit (not just the fan) to be RCD protected.

In reality, of course, the chances of RCD protection for a ceiling fan ever achieving anything useful must be close to zero, but we are talking about regulations, not realities.

Kind Regards, John