LED tube flashing on and off

[johnt]

I installed an LED tube in a loft but it flashes rapidly on and off. Connected to a 13amp plug and plugged into a socket, the tube works fine. But wired into the lighting circuit via a switch, the voltage at the switch fluctuates rapidly when switched on and the tube flashes. I'd be grateful for an explanation and solution.

 

[*-jester-*]

LED Tube? We night need a little more info to diagnose this problem.
Can you attach a photo of this "tube" or supply more tech spec please.

One thing to consider is that some electricians wire the loft light circuit in parallel with the landing light (i.e. it switches off with the landing light) so that the loft light is never inadvertently left switched on, it could be some interference with that.

 

[snowhead]

Has the landing light, or the source for the loft lighting power, got a dimmer on it?

 

[DPG]

You haven't tapped into a switch line by mistake have you?

 

[Midwest]

Or switched the neutral by mistake, or just got a duff fitting.

 

[johnt]

Thanks all for your replies. It's a Sylvania single 5ft IP20 pipe fitting with T5 integrated LED tube from Wickes. There was no circuit for a loft light - I used the upstairs lighting circuit as the source of power. There are no dimmer switches on the circuit. No, I haven't tapped into a switch line and I haven't switched the neutral. The fitting is OK - I put a plug on it and tested it from a socket - it worked fine then.

 

[*-jester-*]

Hmm interesting!
Have you tried a different light fitting in place of the LED Tube. Please tell us the result.

 

[ruston]

Have you tried another type of light on this circuit or tested it's integrity?

^^^^^^ Sorry did not see your post.

 

[littlespark]

Extractor fan in bathroom? Was that running when your LED is flashing?

I’ve got one just now where a 12v shower light flashes once every 5 to 7 seconds but only when the fan is running. Changed driver, same thing.

Check your supply voltage on socket circuit and lighting. They should be the same, or 1 or 2 volts out.
Only other thing could be loose connection in switch??

 

[johnt]

Thanks to jester and ruston - no I haven't tried a different light fitting. I should do, but I'd like to return the third time to this property with a solution - it's getting embarrassing.
In answer to littlespark, no, there was no extractor fan running. The supply voltage on the lighting circuit was around 243V; I didn't check the socket. I thought it might be a loose connection so I checked everything, twice! And changed the switch.