UK Can I use a 3 pole isolation switch as a basic trigger switch?

[Cablemonkey]

Hello all, a little help would be much appreciated. I would like my extractor fan to have its own trigger switch, not dictated by the bathroom light switch. However, I’d like that switch to have an indicator flag. I’ve seen the ones on tlc but these are a 3 pole isolation switch. How could this be wired as purely a pull cord trigger switch? Many thanks

 

[telectrix]

as you'e drawn it, looks OK. with the 3 pole isolator left in the ON position, all you need is a pull cord lighting switch to switch the fan on. switching off the pull cord, the fan will overrun according to the timer setting. you canperhaps drill the pull cord switch cover and fit a neon .

 

[Cablemonkey]

Cheers.
Is like to use the following switch as the pull cord trigger-due to the flag indicator.

Any issues in using another 3 pole isolation switch you reckon? Switched live and live, as long as connected in the same line, opposite terminals should provide that on/off....

 

[radiohead]

For a normal rather than 3 pole switch you will need a pullswitch with a neon as otherwise you will have no way of knowing whether the trigger switch is in the on or off position, for example if someone comes to the bathroom and finds the fan already running. Crabtree do a 16a DP P/S with a neon that I use in these situations. An alternative is to use a retractive switch as the trigger although this will really need to be outside the bathroom,

 

[Cablemonkey]

Thank You. How would you wire that switch ref my diagram above? I’m sure I read on another thread about needing a neutral for the neon.

 

[telectrix]

you will need a N for the neon unless....you connect the neon across L and S/L. then the neon will be ON when switch is OFF, and vice versa. this method was used some while ago by MK on light switches to make them easy to find in the dark. iirc, the neon was green and had a lear lens in front of it. so the switch, when off, glowed in the dark.

 

[davesparks]

Cheers.
Is like to use the following switch as the pull cord trigger-due to the flag indicator.
View attachment 55801
Any issues in using another 3 pole isolation switch you reckon? Switched live and live, as long as connected in the same line, opposite terminals should provide that on/off....

Yes you can use that as your trigger switch, there is no problem with that.

Do you really want an overrun on a fan with its own switch? Normally if the fan is on a seperate switch you wouldnt have the overrun or seperate 3 pole isolator.
[automerge]1581871684[/automerge]

For a normal rather than 3 pole switch you will need a pullswitch with a neon as otherwise you will have no way of knowing whether the trigger switch is in the on or off position, for example if someone comes to the bathroom and finds the fan already running.

That's why the OP wants to use the three pole switch, it has a mechanical indicator to show the position.

 

[radiohead]

You could use one of these, a momentary action pullswitch. No indication needed.

3190RCWHI | MK Electric White Pull Cord Switch, 6A 2 Way | RS

uk.rs-online.com

 

[Cablemonkey]

Great shout with the momentary switch!
I take it that would be back to just having the live and switched live going to it....no other gotchya’s.....??
Thanks!!

 

[freddo]

I take it that would be back to just having the live and switched live going to it....no other gotchya’s.....??
Thanks!!

Yes, the fan will of course only run for the time delay set in the fan.

this method was used some while ago by MK on light switches to make them easy to find in the dark. iirc, the neon was green and had a lear lens in front of it. so the switch, when off, glowed in the dark.

That's an MK K3041 neon plateswitch locator, if you ever need one. They are not effective after the painter has painted around all the switches.

 

[shaun1]

A neon across the switch terminals would probably not work in this setup, as the neon may well pass enough current to constantly trigger the fan.

 

[smarty1972]

To use the flag switch you pictured just take the permanent live (c) and place in live in on flag switch and from live out on flag switch back to s/live on 3 pole isolator/fan