DIY Folks / Electricians

Status
Not open for further replies.
PTR

PTR

Striker
Let's face it, 2019 wouldn't be complete without yet another DIY help thread from me!

SitRep: I've installed an inline extractor fan in my loft, with the ducting to external and the ceiling rose/vent - that's all sorted.
I've tested the fan on the bench using a couple of 3-pin plugs as supplies, and it works correctly.

Problem is, I can't figure out the wiring.
The fan needs - Permanent Live, Switched Live and Neutral
I have access to the bathroom switch, which shows 230V across the switch with a Black and a Red wire (and earth). When switched on, the voltage drops to 0V.
The light itself has 1 pair of black and red wires (+earth)

That's all I have to work with. I can't quite figure out how to get all 3 connections that I need. I guess I need to take from both the switch and the light? Possibly the perm live and neutral from the switch, and switched live from the light itself?

(Yes, I have an isolator switch that I'll fit too - so everything will ultimately terminate there, but until I can locate the supplies, there's not much point fitting that yet).

Any ideas?
 


PTR said:
Let's face it, 2019 wouldn't be complete without yet another DIY help thread from me!

SitRep: I've installed an inline extractor fan in my loft, with the ducting to external and the ceiling rose/vent - that's all sorted.
I've tested the fan on the bench using a couple of 3-pin plugs as supplies, and it works correctly.

Problem is, I can't figure out the wiring.
The fan needs - Permanent Live, Switched Live and Neutral
I have access to the bathroom switch, which shows 230V across the switch with a Black and a Red wire (and earth). When switched on, the voltage drops to 0V.
The light itself has 1 pair of black and red wires (+earth)

That's all I have to work with. I can't quite figure out how to get all 3 connections that I need. I guess I need to take from both the switch and the light? Possibly the perm live and neutral from the switch, and switched live from the light itself?

(Yes, I have an isolator switch that I'll fit too - so everything will ultimately terminate there, but until I can locate the supplies, there's not much point fitting that yet).

Any ideas?
Click to expand...
If there is just a red and black in the switch? that is just a live and switched live, the neutral you will have to pick up from the light fitting.
You should also get your live,sw live and neutral into a fan isolator before you go to the fan itself buddy so you can isolate the fan safely afterwards.

Easiest thing to do is run a 3 core and earth into the light fitting, picking up your live neutral and sw. live there, into a fan isolator then onto the fan
 
Last edited:
Boz33 said:
If there is just a red and black in the switch? that is just a live and switched live, the neutral you will have to pick up from the light fitting.
You should also get your live,sw live and neutral into a fan isolator before you go to the fan itself buddy so you can isolate the fan safely afterwards.

Easiest thing to do is run a 3 core and earth into the light fitting, picking up your live neutral and sw. live there, into a fan isolator then onto the fan
Click to expand...
My light fitting doesn't have live, neutral and sw. It only has black, red and earth. So I guess that's sw and neutral? Then I need to pick up a permanent live from somewhere else? (possible the switch supply?)

(Yes, its all going to an isolator switch, of course - I'm not that stupid lol).
 
Last edited:
PTR said:
My light fitting doesn't have live, neutral and sw. It only has black, red and earth. So I guess that's sw and neutral? Then I need to pick up a permanent live from somewhere else? (possible the switch supply?)
Click to expand...
Did you not get a wiring diagram with the fan?
 
Boz33 said:
If there is just a red and black in the switch? that is just a live and switched live, the neutral you will have to pick up from the light fitting.
You should also get your live,sw live and neutral into a fan isolator before you go to the fan itself buddy so you can isolate the fan safely afterwards.

Easiest thing to do is run a 3 core and earth into the light fitting, picking up your live neutral and sw. live there, into a fan isolator then onto the fan
Click to expand...
This. We have a winner.
PTR said:
My light fitting doesn't have live, neutral and sw. It only has black, red and earth. So I guess that's sw and neutral? Then I need to pick up a permanent live from somewhere else? (possible the switch supply?)

(Yes, its all going to an isolator switch, of course - I'm not that stupid lol).
Click to expand...
There will be a junction box in the loft somewhere if thats all you have at the light and no neutral at the switch.

Trace the twin and earth from the light fitting and see where the joint is. The switched live neutral and permanent will be there. Then just a 3core and earth from that point to your fan isolater then from the isolater to the fan.
 
Last edited:
WHD said:
Did you not get a wiring diagram with the fan?
Click to expand...
Yes, it tells you what the requirements are. Live, Switched live and Neutral.

That's all well and good when you have easy access to these things. When you are in the loft, and digging around in 2 feet of insulation, it gets a bit more tricky understanding exactly what different things actually do. Black and Red cables in the light mean different things to Black and Red cables in a switch, for example. Yep, old style wiring, sadly
 
PTR said:
Yes, it tells you what the requirements are. Live, Switched live and Neutral.

That's all well and good when you have easy access to these things. When you are in the loft, and digging around in 2 feet of insulation, it gets a bit more tricky understanding exactly what different things actually do. Black and Red cables in the light mean different things to Black and Red cables in a switch, for example. Yep, old style wiring, sadly
Click to expand...
Just updated the post.
 
PTR said:
My light fitting doesn't have live, neutral and sw. It only has black, red and earth. So I guess that's sw and neutral? Then I need to pick up a permanent live from somewhere else? (possible the switch supply?)

(Yes, its all going to an isolator switch, of course - I'm not that stupid lol).
Click to expand...
You best get the fucker right, otherwise you a f***ing toast mate!!
 
PTR said:
Yes, it tells you what the requirements are. Live, Switched live and Neutral.

That's all well and good when you have easy access to these things. When you are in the loft, and digging around in 2 feet of insulation, it gets a bit more tricky understanding exactly what different things actually do. Black and Red cables in the light mean different things to Black and Red cables in a switch, for example. Yep, old style wiring, sadly
Click to expand...
There is definitely a junction box there somewhere. The light will have been a ceiling rose at some point and will have been moved, hence you only have a switched live and neural at the light.

I take it there is only 1 light in the bathroom?
 
  • Like
Reactions: PTR
tunstall birdman said:
You best get the fucker right, otherwise you a f***ing toast mate!!
Click to expand...
Nah, have to be daft to actually cause bother. I have a multimeter and the circuits are isolated propely - so we can test it safely enough. Worst case is tripping a breaker tbh.
yamar1 said:
There is definitely a junction box there somewhere. The light will have been a ceiling rose at some point and will have been moved, hence you only have a switched live and neural at the light.

I take it there is only 1 light in the bathroom?
Click to expand...
Correct.
This is what I was telling my dad, but he wouldn't listen.

I can take that switched live and neutral - then add a junction from the perm live in the switch to get me eveything I need to drive this fan, yes?
 
Last edited:
The permanent will probably be directly above the light in connector blocks.And you dont need to confuse yourself with a fan isolator if theres windows in your bathroom even though it is advised.
 
PTR said:
Yes, it tells you what the requirements are. Live, Switched live and Neutral.

That's all well and good when you have easy access to these things. When you are in the loft, and digging around in 2 feet of insulation, it gets a bit more tricky understanding exactly what different things actually do. Black and Red cables in the light mean different things to Black and Red cables in a switch, for example. Yep, old style wiring, sadly
Click to expand...
Ok, I managed to wire mine up in a similar situation, but I already had the live feed.
 
  • Like
Reactions: PTR
WHD said:
Ok, I managed to wire mine up in a similar situation, but I already had the live feed.
Click to expand...
I've done one before tbh. Seems every single house I've worked in has had a totally different lighting circuit. f***ing annoying tbh.
 
PTR said:
Nah, have to be daft to actually cause bother. I have a multimeter and the circuits are isolated propely - so we can test it safely enough. Worst case is tripping a breaker tbh.

Correct.
This is what I was telling my dad, but he wouldn't listen.
Click to expand...
;)

Btw, I've had this from people getting in the road, when I have been break dancing on the floor and them f***ing up my moves.
 
Status
Not open for further replies.

Back
Top