PIR sensor not switching lights on

[Steve A]

Hi sparks
I am trying to fit a PIR sensor to a downstairs bathroom, replacing the existing pull cord
As per the instructions I have wired the sensor. When switching the trip back on, the led bathroom lights (4 in total) illuminate, but are dimly lit (by about 50%). Leaving in this state, does not change over time
Activating the sensor causes the lights to be fully illuminated briefly (1 or 2 seconds) then automatically switches back to 50%
Initially i suspected the PIR, but this is now a new replacement, with the same fault
I have trial wired the sensor to an external supply (13 amp socket) and the sensor and lights function correctly
I suspect there is a neutral problem with the existing bathroom lighting
Any assistance in locating the fault will obviously save my DIY integrity and a few quid
Many thanks in advance
Steve A

 

[Let me think]

Interesting. Could be a number of reasons, but would really need to get a electrician in to check.

All you could reasonable be expected to do yourself is to check they are no loose cables or connections in any of the easily accessible fittings i.e. all downlights and also at the light switch.

Someone else on the forum make be to shine some light on this (pardon the pun)

 

[James]

Make and model of pir?

 

[snowhead]

Was there already a Neutral at the Pull cord location?

 

[Let me think]

Interesting. Could be a number of reasons, but would really need to get a electrician in to check.

All you could reasonable be expected to do yourself is to check they are no loose cables or connections in any of the easily accessible fittings i.e. all downlights and also at the light switch.

Someone else on the forum make be to shine some light on this (pardon the pun)

Dohh, as snowhead as pointed out you may not have a neutral at the pull cord/PIR location (just because there is blue or black wire at doesn't mean there is an actual neutral, could be an unmarked just switch live), which may explain the problem.

Would you be able to provide photos?

 

[telectrix]

yep. loss of N. a load across the L and S/L can illuminate , using the S/L as a false N. this was used by MK with their switch finder illumination idea.

 

[Steve A]

Was there already a Neutral at the Pull cord location?

Hi No neutral at the pull cord
[automerge]1594213585[/automerge]

Dohh, as snowhead as pointed out you may not have a neutral at the pull cord/PIR location (just because there is blue or black wire at doesn't mean there is an actual neutral, could be an unmarked just switch live), which may explain the problem.

Would you be able to provide photos?

Your correct. no neutral at the switch, but the problem exists when i use the neutral from the old ceiling rose.

Sorry no pics, its not my house

 

[Taylortwocities]

Hi No neutral at the pull cord
[automerge]1594213585[/automerge]

Your correct. no neutral at the switch, but the problem exists when i use the neutral from the old ceiling rose.

Sorry no pics, its not my house

OK. So what does your meter tell you - volts-wise - both on the input to the PIR, and the switched output?