bathroom lights and ceiling fan controlled by PIR

[deridere]

Hi all, I've been reading this forums for the last 5 years, but never registered as I always found my problem described by someone. Can't find exact description for the following:

Bathroom with 12V fire rated spot lights and mains powered built in timer in-line fan( Mixflo MF100T), to be controlled by ceiling mounted PIR with presence / LUX /timer control, and all this connected to 3 pole isolator. Fan is to installed in the loft above the bathroom.

What the best way to wire all this?

Idea is for the fan and lights to come ON when someone enters the bathroom, and stay on until no movement is detected( LUX control want be used at the moment). And then fan needs to continue running for pre-sett time.

Thanks for the advice.

 

[Dave OCD]

Hi all, I've been reading this forums for the last 5 years, but never registered as I always found my problem described by someone. Can't find exact description for the following:

Bathroom with 12V fire rated spot lights and mains powered built in timer in-line fan( Mixflo MF100T), to be controlled by ceiling mounted PIR with presence / LUX /timer control, and all this connected to 3 pole isolator. Fan is to installed in the loft above the bathroom.

What the best way to wire all this?

Idea is for the fan and lights to come ON when someone enters the bathroom, and stay on until no movement is detected( LUX control want be used at the moment). And then fan needs to continue running for pre-sett time.
Thanks for the advice.

Hi I'm new here too but will try and answer this one.

I assume the lights are on individual transformers above the ceiling ? Also the three pole isolator would just be for the fan?
If those assumptions are correct I'd still suggest an isolating switch [perhaps double pole pull switch with neon ?] before the PIR and then run a twin and CPC from that to the P.I.R. Then you can run a 3 core and CPC to the fan isolator and take the feed to the transformers from the switched live and neutral terminals on the feed side of the isolator. Apart from that it's just a case of another 3 core and CPC from the isolator to the fan, obviously making sure that both fan and P.I.R have adequate I.P. ratings for their installed positions with reference to zones. Hopefully this all makes sense ?

 

[NDG Elecs]

Basically the PIR is replacing the switch, no more no less. Your fan needs a permanent live, a switched live and neutral. Should be a doddle if you have loft access. The PIR may need a neutral too, not just live in and out.

 

[deridere]

Hi I'm new here too but will try and answer this one.

I assume the lights are on individual transformers above the ceiling ? Also the three pole isolator would just be for the fan?
If those assumptions are correct I'd still suggest an isolating switch [perhaps double pole pull switch with neon ?] before the PIR and then run a twin and CPC from that to the P.I.R. Then you can run a 3 core and CPC to the fan isolator and take the feed to the transformers from the switched live and neutral terminals on the feed side of the isolator. Apart from that it's just a case of another 3 core and CPC from the isolator to the fan, obviously making sure that both fan and P.I.R have adequate I.P. ratings for their installed positions with reference to zones. Hopefully this all makes sense ?

Dave, thanks for the quick reply.

- lights are using one transformer - 1-50W 12V DC Non-Dimmable Constant Voltage LED Driver.
- wife would not allow me to rip the wall for additional isolating switch(for the LED driver), is it possible to use the three pole isolator for the the whole bathroom lights/ventilation setup?

I should have started with describing the current setup before the update:
I've got free access to the loft, so I can see 3 core and CPC going from junction box to the three pole isolator,then to the old noisy blocked fan, and I've got the lighting circuit going to a pull cord, and two transformers feeding 5x 50W halogens. They have used 0.75mm two core flex from transformers to halogens?! Is this right cable to use for feeding my new LED from new transformer?

 

[Leesparkykent]

Dave, thanks for the quick reply.

- lights are using one transformer - 1-50W 12V DC Non-Dimmable Constant Voltage LED Driver.
- wife would not allow me to rip the wall for additional isolating switch(for the LED driver), is it possible to use the three pole isolator for the the whole bathroom lights/ventilation setup?

I should have started with describing the current setup before the update:
I've got free access to the loft, so I can see 3 core and CPC going from junction box to the three pole isolator,then to the old noisy blocked fan, and I've got the lighting circuit going to a pull cord, and two transformers feeding 5x 50W halogens. They have used 0.75mm two core flex from transformers to halogens?! Is this right cable to use for feeding my new LED from new transformer?

Might be worth getting a sparky in deridere. As the work you intend to do is in a bathroom it's notifiable.

 

[deridere]

Basically the PIR is replacing the switch, no more no less. Your fan needs a permanent live, a switched live and neutral. Should be a doddle if you have loft access. The PIR may need a neutral too, not just live in and out.

That's what I thought, I was even thinking to use the pullcord hole to put the PIR in.
But what's bugging me is how to connect the whole bathroom lights/ventilation to one isolator. don't like using the CU MCB, when I need to change a light-bulb. And can the fan timer keep the fan ON even when the PIR switches the lights OFF?
PIR is TLC item number SM SLFM360 https://www.tlc-direct.co.uk/Technical/DataSheets/Smiths/SMSLV360E_Install.pdf
After drawing diagrams all afternoon, I've got a bit of a brain freeze...

 

[deridere]

Might be worth getting a sparky in deridere. As the work you intend to do is in a bathroom it's notifiable.

Thanks Leesparkykent , yes you are right. Might have to give you a call as you are in Kent. So far the work is in the loft, but it could move to the bathroom. 10 Minutes Ago

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[Leesparkykent]

Thanks Leesparkykent , yes you are right. Might have to give you a call as you are in Kent. So far the work is in the loft, but it could move to the bathroom. 10 Minutes Ago

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Where about in kent?

 

[deridere]

Where about in kent?

I'm in Walderslade near Chatham.

 

[Leesparkykent]

I'm in Walderslade near Chatham.

I know the area well.

 

[NDG Elecs]

Might be worth getting a sparky in deridere. As the work you intend to do is in a bathroom it's notifiable.

For peace of mind you should. It's very simple to do and if loft access ok then shouldn't cost a great deal. Have only skim read through the posts but am puzzled as to why you want lights on isolator also.

 

[deridere]

For peace of mind you should. It's very simple to do and if loft access ok then shouldn't cost a great deal. Have only skim read through the posts but am puzzled as to why you want lights on isolator also.

The reason to have the lights on the same isolator is to be able to isolate the PIR/lights if i need to change a bulb. Wife won't allow me to channel the wall to fit second isolator for the PIR/Lights

 

[NDG Elecs]

LEDs generally have a long service life so won't need changing often, so I would use MCB as isolator on them. Or if a lamp fails tape some card over the PIR and wait till lights go off before changing them!

 

[Dave OCD]

That's what I thought, I was even thinking to use the pullcord hole to put the PIR in.
But what's bugging me is how to connect the whole bathroom lights/ventilation to one isolator. don't like using the CU MCB, when I need to change a light-bulb. And can the fan timer keep the fan ON even when the PIR switches the lights OFF?
PIR is TLC item number SM SLFM360 https://www.tlc-direct.co.uk/Technical/DataSheets/Smiths/SMSLV360E_Install.pdf
After drawing diagrams all afternoon, I've got a bit of a brain freeze...

You could use one isolator for the lights and fan, if you're happy with that you could simply fit a switched/fused spur [double pole] at an accessible place in the loft in the permanent supply before the PIR - you could also put a 3a fuse [or even smaller] in it to provide better protection for the low power consumption led's and fan. The fan will run on after the PIR switches off as that function is powered by the permanent live, the switched live just starts the fan up.