Mains domestic LED lamps on 3-way switch glow faintly in one 'off' arrangement

[Nick Willder]

On my landing are three connected lights. They have 230v LED bulbs. There are three switches - one obviously an intermediate switch. In one of the four 'off' arrangements of the switches, the LEDs glow faintly. Does anyone have a theory on where this current might be leaking to? Thanks.

 

[Midwest]

Its possibly an induced voltage, on the cabling for your intermediate switching. You could try some other LED lamps, or fit a snubber. This question gets asked quite often;

Flickering LED bulb when off - https://www.electriciansforums.co.uk/threads/flickering-led-bulb-when-off.137798/

 

[Lucien Nunes]

It probably happens only in one of the permutations because of the layout of the common and strapper cores in 3-core & earth cable between the switch points. I.e. If PL and SL are connected to the two adjacent cores lying to one side of the CPC for the whole run, then the capacitive leakage is sufficient to light the lamps. In switch positions that select cores on opposite sides of the CPC, the mutual capacitance is lower and the leakage is too low to have an effect. Remedy as above.