Smoke alarm 3rd core, WHY ?

[jamestaylorchat]

Hello fellow sparks, how are we ?

I am slightly embarrassed about asking this but here goes,

I have never realy understood why you need a 3rd core when wiring smokes, live, neutal and earth i get, but why do you need a switch wire exactly,

what is its job ?

 

[Fin170]

Live, neutral and the 3rd is the interlink/com. It's in the manual with a free Fire Alarm sticker usually

 

[monkeyelectric]

To sound the other smokes if one is triggered

 

[amlu]

third wire is for linking them together, when one gets triggered then all of them will sound the alarm.

 

[MDJ]

the third core is the switched link to other smokes, when one smoke rings the interconnect or third wire sends a signal to the others on the circuit, Happy friday by the way.

- - - Updated - - -

haha 3 replies whilst I replied, we are quick tonight guys.

 

[jamestaylorchat]

I thought that was it but wasent sure.

Now why the trhird core when wiring a fan switch from a bathroom switch ?

 

[monkeyelectric]

For the overrun after the light has been switched off

 

[MDJ]

come on James, why do you think there is a third core?

 

[Resu]

Switched live, neutral and permanent live to supply timer.

 

[jamestaylorchat]

I just drew out a simple oneway bathroom switch with a fan switch being feed of it.

Common = per live
L1= SW Live
L2=fan switch 3rd core

Switch switched, current goes down L2 and runs fan for however long the time is set for,

correct ?

 

[NadHuh]

Even I knew this and I'm a first year apprentice

 

[MDJ]

yup absolutely love Friday's here

 

[monkeyelectric]

When you said in your first post hello fellow sparks just how much of a spark are you?

 

[onfire25]

No......you need to go from the switch to a TP fan isolator then the fan.

Common - perm live at fan isolator (brown)
S/L - S/L at fan isolator (black....remember to sleeve)
Neutral - Neutral (gray......remember to sleeve)

Then wire from the isolator to the fan!

Failing that......rtfm.....or call a professional spark

 

[jamestaylorchat]

HEY HEY HEY !!!!

Settle down Lads, there is all man and all sparks right here

Give me a bit of trunking or conduit and watch me go, but when it comes to wiring, i strugle,