Light bulb always on

[85stu]

Hey

So I have a light at the top of the stairs that always gives off a faint light, even when it is off (pic attached). My first assumption was an issue with the electrics, so I swapped in a different bulb and this didn't happen with the other bulb. I've tried three other bulbs now and they all switch off completely. So maybe it is the bulb? But screwing this bulb into a different light doesn't produce the same effect.

Not sure what to make of this.

 

[85stu]

The light in the attached pic makes it look much brighter than it actually is! The first time I saw it I wasn't sure it was still giving off light, it is quite faint.

 

[JohnD]

Is the one in your pic "dimmable?"

 

[85stu]

Is the one in your pic "dimmable?"

The bulb - not sure

The light - nope, just a switch

 

[RandomGrinch]

Do you have two way switching - a switch at the bottom and one at the top of the stairs?

 

[85stu]

Do you have two way switching - a switch at the bottom and one at the top of the stairs?

I do!

 

[JohnD]

The bulb - not sure

The light - nope, just a switch

It's the bulb I meant.

I expect you have a tiny amount of electrical "leakage" usually by capacitive coupling in the cable. More common with 2-way switching. There are some ways round it, but easiest just to find a lamp that doesn't do it.

 

[85stu]

It's the bulb I meant.

I expect you have a tiny amount of electrical "leakage" usually by capacitive coupling in the cable. More common with 2-way switching. There are some ways round it, but easiest just to find a lamp that doesn't do it.

Okie doke, so I should just swap the bulbs?

Is it an issue/potentially dangerous?

 

[JohnD]

Yes

No

 

[RandomGrinch]

Don't try this at home

Not an issue at all, some actually like it as a sort of night light!
The more expensive bulbs that I have bought, don't tend to glow - possibly with a built in snubber resistor/capacitor.
If you really want to stop the glow, but keep the bulb, you can buy a capacitor to mount in the ceiling rose - although the effort isn't usually worth it

 

[85stu]

Thanks!

It doesn't bother me at all honestly, I was just worried it was a sign of dodgy electrics.

 

[RandomGrinch]

Thanks!

It doesn't bother me at all honestly, I was just worried it was a sign of dodgy electrics.

It's not even costing you any more money in electricity. The tiny current was always there, just dissipating quietly through the old bulb, without you knowing

 

[sparkwright]

Thanks!

It doesn't bother me at all honestly, I was just worried it was a sign of dodgy electrics.

Unfortunately, it's very common with today's bulbs - and it's not a sign of dodgy electrics.

 

[ericmark]

With AC when wires are placed close together you can get inductive and capacitive leaking, so bulbs have leak resistors to dissipate this, but the size of the resistors vary, so you can see a glow with some bulbs, but there is no problem with this.

 

[winston1]

It's not even costing you any more money in electricity. The tiny current was always there, just dissipating quietly through the old bulb, without you knowing

The resistance of a cold tungsten bulb is very low giving a very small IR loss. With an LED the resistance is higher giving a higher IR loss. There is no loss in the capacitive coupling in either case.