Low current still reaching light sockets even when off?

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A couple of months ago I changed all of our downstairs light fittings and all seemed absolutely fine - no problems in that time and all work as expected etc.

Yesterday I was experimenting with some lightbulbs with varying brightness and oddly when screwing in a dim 1w bulb, it still gave off a slight glow even when the light wasn't actually turned on. Not fully on (when a 1w bulb is obviously quite dim anyway), but almost the kind of level you'd get from an emergency light. I tried this with all four light fittings just to check and strangely two of them did this while the other two didn't (bulb was fully off if the switch at the wall was).

I've wired all of the light fittings up the same so I can't work out why this would be the case in some but not others. In three of the fittings there are multiple of each wire, meaning I had to identify the correct switch live etc and connect two of the live wires to a wago connector block, so I wondered if I might've done something slightly wrong there, but then the bathroom light is one where this issue happens, however that light is on its own individual circuit (with its own individual fuse switch etc) and for that there literally is just a single of each live, neutral and earth wire, so I can't figure out how that could possibly have been wired incorrectly!

Of course had I never experimented with this very low wattage bulb I'd have never even known this to be an issue - with literally any other bulb this doesn't happen at all, even with as low as a 3w energy saving bulb.

Have I likely wired up something slightly wrong in a couple of them? Or is it possible that those 1w bulbs just require such little power that simply being screwed in to a socket that's connected to the mains (albeit switched off) is still enough power to make them glow faintly.
 
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The cable to the switch will have a Permanent Live wire and a Switched Live wire. When the switch is ON these are connected together in the switch. When the switch is OFF there is a capacitive coupling along the cable between the two wires which allow a very small amount of power to pass from the Permanent Live wire to the Switched Live wire. This power is enough to make a low power lamp glow when the switch is OFF.
This leaked power can be absorbed by a snubber connected across the lamp

Capacitor 0.047uF micro Farads 250 volts AC in series with Resistor 100 ohms

Which come pre-packaged as a contact suppressor from RS Components.

As a contact suppressor it would be fitted between Live and Switched Live at the switch BUT as a snubber it has to be fitted between Switched Live and Neutral at the lamp..

( If there is a Neutral at the switch it may be more convenient ( space wise ) to fit it in the back box of the switch )

KEMET RC Capacitor 470nF 100Ω Tolerance ±20% 250 V ac, 630 V dc 1-way Through Hole PMR209 Series

RS Stock No. 206-7869
Manufacturer Evox-Rifa
Manufacturers Part No. PMR209ME6470M100R30


There are other sources

Read more: https://www.diynot.com/diy/threads/...till-glow-when-isolated.555283/#ixzz6muQ6q3hd
 
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Thanks for the quick reply. So just to double-check then, it's not necessarily a problem per se, more just a natural side-effect with a very low powered bulb?

As I say it was primarily just from experimenting with varying bulb wattages, for the sake of ease I can live with a slightly brighter bulb that doesn't do this in those two light fittings - I essentially just thought it might be worth checking I didn't accidentally have current running where it shouldn't be!
 
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