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Induced voltage or dodgy wiring?

Farmboy
A domestic Flat has 1 * 6A lighting cct, 1 * 32 RFC, and 1 * Ckr cct. Supply is TN-S.

A 2G plate switch in the kitchen (which has a flat roof / attic space above other rooms) is fed by a twin and earth - one core feeds the commons of the two switches, while on one switch the other core supplies two downlights. A sheathed single core from the second switch feeds two wall lights. Each downlight is fed by a single T&E. One wall light has a T&E loop in / loop on, the other light just a T&E in. All wiring is concealed in walls.

At the downlights, 244V (L-N) appears with the switch turned on (using a MFT). However, with the switch off, approx. 23V still shows. With the switch off and a lamp installed in either fitting, while testing at the other, V=0. The 23V does not appear at the wall lights.

With the CB’s turned off on the other ccts at the CU, the 23V remained, as when the N’s were disconnected also. V=0 with the lighting CB off.

L/N – E IR test with all switches on is > 300MOhms.

Before hunting about for things like dodgy connections in JB’s in a grotty/dirty loft space, any ideas what may be going on please?


Thanks


F
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    The really good engineers from in earlier era keep both hands behind their backs when inspecting  live wiring, or looking into machines with whirling sharp bits, and look rather like Prince Charles does on a Royal visit.  For testing at least one hand stays behind the back, that way you do not become the load resistor that completes a circuit, and if the worst happens you have a spare one behind you.

    Folk raised in the era of interlocked safety guards and so on may be caught out when the power stays on even with the covers off.
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  • 0
    The really good engineers from in earlier era keep both hands behind their backs when inspecting  live wiring, or looking into machines with whirling sharp bits, and look rather like Prince Charles does on a Royal visit.  For testing at least one hand stays behind the back, that way you do not become the load resistor that completes a circuit, and if the worst happens you have a spare one behind you.

    Folk raised in the era of interlocked safety guards and so on may be caught out when the power stays on even with the covers off.
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