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Evening all,

Visited a customer yesterday who said their lamps were blowing regularly in the living room light fitting. I took the light fitting down and visually it looks fine. Its a metal fitting with 3 arms with an SES lamp holder on each. I removed the lamps and insulation tested the fitting with 999+Mohms as the result. All good. I then turned my attention to the wiring. R1 R2 from the light point to the board was 0.62. Insulation res for the circuit was 999+Mohms L-N, L-E, N-E, (lamps removed). Zs from the light was 0.88. Supply polarity is fine and the Ze is 0.22.

However there is a voltage of 58V showing from the SW line to earth when the switch is turned off.

The feed has been taken to the light point in t&e and a 3core cable has been taken to the switch. This is a permanent live, neutral and SW line back to the light. A live and neutral is needed at the switch due to a t&e leaving it to feed the kitchen light switch. I disconnected the 3 core either end and insulation res tested it. Again 999+Mohms was the result. When the permanent live is connected at the light point the SW line in the cable becomes live at 58V even though is completely disconnected each end.

I am returning tomorrow to have another look.

Any input would be helpful.

Regards

James
 
Yes that is my thinking, but Ive not seen it on this scale. It is possible though because the permanent Line and SW line are the red and yellow cables. This will be my first port of call in the morning.

Thanks

James
 
Evening all,

Visited a customer yesterday who said their lamps were blowing regularly in the living room light fitting. I took the light fitting down and visually it looks fine. Its a metal fitting with 3 arms with an SES lamp holder on each. I removed the lamps and insulation tested the fitting with 999+Mohms as the result. All good. I then turned my attention to the wiring. R1 R2 from the light point to the board was 0.62. Insulation res for the circuit was 999+Mohms L-N, L-E, N-E, (lamps removed). Zs from the light was 0.88. Supply polarity is fine and the Ze is 0.22.

However there is a voltage of 58V showing from the SW line to earth when the switch is turned off.

The feed has been taken to the light point in t&e and a 3core cable has been taken to the switch. This is a permanent live, neutral and SW line back to the light. A live and neutral is needed at the switch due to a t&e leaving it to feed the kitchen light switch. I disconnected the 3 core either end and insulation res tested it. Again 999+Mohms was the result. When the permanent live is connected at the light point the SW line in the cable becomes live at 58V even though is completely disconnected each end.

I am returning tomorrow to have another look.

Any input would be helpful.

Regards

James

Hi James,what device was used to measure that voltage?
 
Indeed. What was the supply voltage?
 
Yeah, I often get asked "why do my bulbs blow all the time?" Usually there cheap pound shop stuff or the lights are on and off a lot. Wiring shouldn't cause them to blow, although if there's a lot of vibration on the ceiling above, that may affect the life of an incandescent bulb (I mean lamp, bulbs go in the garden!)......tell them to get LED lamps..
 
I assume that the lamps are of the halogen type and therefore the SES screw cap expands and contracts with the heat generated when left on for some time. This makes a small gap between the live contact pin and poor contact reducing lamp life.
 
The problem is called modern living,its not in the makers interest to have the quality too high so that it destroys the market
Its like cars fridges,washing machines etc,the manufacturer needs to sell their product both now and in the future,the poor old wiring or fitting often gets the blame
 
As "sweet212" states "..... their lamps were blowing regularly in the living room light fitting............... "

Check the mechanical action of the light swich (if it hasnt be changed)

...some people gently use light switches
with mutiple loads can degrade contacts , doesn't show up every time /different user!
( Customer may not notice buzzing ... multiple on/off wear)

..but naff lamps /pooly fitted as per others comments....more common cause
( some fittings bake cheap lamps - look for arcing/black-dot on solder blob of bulb)
 
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I assume that the lamps are of the halogen type and therefore the SES screw cap expands and contracts with the heat generated when left on for some time. This makes a small gap between the live contact pin and poor contact reducing lamp life.
i blame it all down to these modern pesticides. how can a bulb flourish when it's bombarded with chemicals? no wonder we get things like this mutation.
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