a simple bathroom fan

[matthew2ts]

i have just bought again b and q (greenwoods) extractor fan.

it has three terminals L1, N, L.

iam connecting the L to the live feed and N to neutral.

when i turn on the power the fan runs for a few seconds then cuts out. it will not run again when it is switched on or off then back on again. however when left for several hours off then turned on again it runs for a few seconds again then cuts out.

i have replaced the fan with a new one from bandq and im still getting the same result.

to test the fan i wired a plug up on a piece of wire with the L to live on the plug and the other wire to n. the fan cut out again after several seconds.

what is going on? is it something simple iam doing wrong?

 

[andy]

i have just bought again b and q (greenwoods) extractor fan.

it has three terminals L1, N, L.

iam connecting the L to the live feed and N to neutral.

when i turn on the power the fan runs for a few seconds then cuts out. it will not run again when it is switched on or off then back on again. however when left for several hours off then turned on again it runs for a few seconds again then cuts out.

i have replaced the fan with a new one from bandq and im still getting the same result.

to test the fan i wired a plug up on a piece of wire with the L to live on the plug and the other wire to n. the fan cut out again after several seconds.

what is going on? is it something simple iam doing wrong?

connect L1 and L together. problem solved.

 

[matthew2ts]

thanks ill go and try that now,

but will the over run timer still come on?

when the live is switched off?

 

[andy]

thanks ill go and try that now,

but will the over run timer still come on?

the timer can only come on if you connect a permanent live and switched live. from what you have said, you only havent connected L1 so it cant run in timer mode. and since L1 isnt connected to give it the signal to start, thats why its cuttin out after a few seconds.

see for reference for how to connect it properly so itll over run

when the live is switched off?

and does stuff normally work when the live is switched off?

 

[matthew2ts]

thanks. the scales have fallen from my eyes


i was working on the assumption that L was the main live not L1.

 

[andy]

thanks. the scales have fallen from my eyes


i was working on the assumption that L was the main live not L1.

N is neutral. altho even you knew that.

L is permanent live.

L1 is switched live


L is always live, and once L1 is live, the fan will come on. once L1 goes dead, the fan will continue to run from L, until it times out.

if you dont have a switched live, you connect L1 and L so itll come on as long as the mains is there

you connected the live to L, so altho this was correct, ou werent giving it a switched live to L1 so the fan will stay off. this explains why it started for a few seconds

 

[matthew2ts]

thanks again. its working fine now. and thanks for the explanation of what the fan was doing


i want to vent another room. the switch live connection is easy to get a wire from ie off the nearest light. but the permenant live is difficult to get a cable from to where i want to site the fan. ie there are joists and metal suspended ceiling i don't want to punch full of holes.

there is a plug socket nearby. is it safe to take a live feed off this? this is 30 amp not 5amp but its mixing two fuses this must be wrong ? should i make holes in the ceiling?

and what is the best cable for the live feed. i used twin and earth on the first fan connected the red to live and cut the other two back. this seemed a bodged job what is the best way to do it?

 

[breezer]

what you propose is dangerous so the answer is NO

as has also been said look in the for refernce section, it shows how it should be done

 

[mapj1]

What you could do is take both L and N from the socket, through a fused switch with a 5 A fuse in it, and then on to the fan, but L and N from differnt circuits should never be mixed - it can cause dangerous and confusing problems when people try to work on the circuit having isolated one half and not the other.

 

[bathjobby]

i want to vent another room. the switch live connection is easy to get a wire from ie off the nearest light. but the permenant live is difficult to get a cable from to where i want to site the fan.

If that is in a loop, it will also have N and perm L as well as switched L.