light stays on

[Rob W]

Hello, tenant's landing light stays glowing when either landing switch turned off or the switch at the bottom of the stairs turned off.

When i trip the circuit breaker the light goes off.

Possible the tenant had the light on all day and taking time for the LED bulb to discharge when switched off ?

Any suggestions welcome please, thankyou. 

[elite]

I've seen this before where switches with indicator lamps are installed on switches. Guess it could be a faulty/dirty switch or neutral is being switched rather than the line

[ProDave]

When you say stays on, you mean glows VERY dim and can only be seen when it is dark?  If so capacitive coupling between adjacent L cores in a 3 core 2 way switching cable can cause this.  This can sometimes be cured by reconfiguring the usage of the 2 way switching cables to put the switched L cores either side of the earth.  Or fit a snubber in parallel with the light.  Or just try different types of light bulb.

 

If it is staying on at full brightness then you have a different fault.

[saveasteading]

I have a ceiling light with 3 led bulbs in it and one of them shines gently all night.

 

If i recall, it is taking energy from the inductance ( no something else) always present at a live cable. The same thing that encourages flies to circle a light that is off.

[Andehh]

We have a touch sensitive mirror that does this. In the pitch darkness you can slight light from the LEDs but its probably 2% of the actual ''on'' illumination of the light,

 

Always wondered why myself...

[Temp]

An electrician should be able to fit a capacitor that makes the light go out.

 

It doesn't actually stop the power being  consumed but that's normally tiny.

[Temp]

In most cases it's caused by the capacitance between live and switched live in the drop from light or junction box down to the switch. Power effectively bypass the open switch to get to the light.

 

With old incandescent filaments their resistance is low enough that the switched live is effectively shorted to neutral by the filament. With LED bulbs that's not the case.

 

One solution is to put a resistor across the LED but that would burn power when the switch is ON.

 

A capacitor in the same place still burns a little power but I don't think it's metered as it's reactive power? I might be wrong about that. 

 

I suspect there are folks on eBay selling magic capacitors to fix the problem but you can buy a general purpose capacitor more cheaply. If I remember correctly it's a 0.1uf class X2 but can't swear to that.

 

[saveasteading]

The bulbs  that do this with me are very old indeed and I think primitive. At the time i was testing led on myself rather than on clients.

When they fail, the replacements aren't doing this

 

[Rob W]

Thanks for all your advice and suggestions. Returned to the tenants today to do some painting, took along a new switch, in case, but wasn't required, as when i re-inserted the bulb it no longer glowed, on & off fine.

No idea why but i have learnt a bit researching all possible reasons for lights glowing !