- Joined
- Nov 6, 2011
- Messages
- 21
- Reaction score
- 7
Ghost busters????
This is great. I get to look like a right wally in front of customer over this one for a while! "Can you come and look at my lights? Something strange is happening." "Er? OK. See you soon". Alls well. I arrive and get given cup of tea. All nice and normal. "Come and look at this" says customer. We go into the hallway, (Bungalow). All energy saving compact flourescent lamps I notice. Good. No dimmers. Also good. New MCB / RCD fuse board. He turns OFF the lights and says "wait and watch this". Im nervous now. Could be a weird one! Wheres the door? Then "Flash"! The lamp in the hall flashes. Once. "There you go" he says. And all the lights in the house do it on a regular cycle, (not all at the same time).
All the lights in the house do the same thing. Further from the fuse board = faster flash interval. I try the "Look inteligent but dont say too much" angle for a while. Then I dissasemble the wiring for the lights in the furthest circuit from the board. Continuity on all L and N conductors. Switching in Live line only. Clean supply from board. Insulation good. ES fittings connected correctly. BUT - lights wired in old style TWO CORE 1mm^2. IE: NO CPC.
Took a while but I got it. The starter circuit in the lamps stores a charge to fire up the tube. When you energise normally the capacitor charges then fires to initiate illumination. No earth wire means residual charge in being "harvested" by the lamp starter circuit from the apparently "dead" supply circuit and nearby cables. When enough charge has been collected the starter circuit fires the lamp but there is no maintaining current to drive it so all you see is a flash. Further down the line and more chance to collect induced charge due to cable proximity etc so the lamps flash faster. The earth conductor in a three core cable will naturaly drain this residual charge to ground.
More tea. Good. Should be re-wired in three core or add cpc to light circuits to comply with regs. Advised customer of solution and need to comply with regs. Got job of re-wiring in correct cable type. Alls well.
Just love these moments (on hindsight). You think you know your trade and that day arrives when you just stand there in front of your customer looking like a total plonker!
Watch out for this one! Look carefully in ceiling roses / lighting JB's etc first. Check in fuse board for missing cpc's perhaps. There may be three core connected to a circuit that starts at the board as two core even! Loop test should pick this one up.
Hope this one helps!
Happy Christmas y'all. Eat, drink, sleep, repeat as neccessary!
This is great. I get to look like a right wally in front of customer over this one for a while! "Can you come and look at my lights? Something strange is happening." "Er? OK. See you soon". Alls well. I arrive and get given cup of tea. All nice and normal. "Come and look at this" says customer. We go into the hallway, (Bungalow). All energy saving compact flourescent lamps I notice. Good. No dimmers. Also good. New MCB / RCD fuse board. He turns OFF the lights and says "wait and watch this". Im nervous now. Could be a weird one! Wheres the door? Then "Flash"! The lamp in the hall flashes. Once. "There you go" he says. And all the lights in the house do it on a regular cycle, (not all at the same time).
All the lights in the house do the same thing. Further from the fuse board = faster flash interval. I try the "Look inteligent but dont say too much" angle for a while. Then I dissasemble the wiring for the lights in the furthest circuit from the board. Continuity on all L and N conductors. Switching in Live line only. Clean supply from board. Insulation good. ES fittings connected correctly. BUT - lights wired in old style TWO CORE 1mm^2. IE: NO CPC.
Took a while but I got it. The starter circuit in the lamps stores a charge to fire up the tube. When you energise normally the capacitor charges then fires to initiate illumination. No earth wire means residual charge in being "harvested" by the lamp starter circuit from the apparently "dead" supply circuit and nearby cables. When enough charge has been collected the starter circuit fires the lamp but there is no maintaining current to drive it so all you see is a flash. Further down the line and more chance to collect induced charge due to cable proximity etc so the lamps flash faster. The earth conductor in a three core cable will naturaly drain this residual charge to ground.
More tea. Good. Should be re-wired in three core or add cpc to light circuits to comply with regs. Advised customer of solution and need to comply with regs. Got job of re-wiring in correct cable type. Alls well.
Just love these moments (on hindsight). You think you know your trade and that day arrives when you just stand there in front of your customer looking like a total plonker!
Watch out for this one! Look carefully in ceiling roses / lighting JB's etc first. Check in fuse board for missing cpc's perhaps. There may be three core connected to a circuit that starts at the board as two core even! Loop test should pick this one up.
Hope this one helps!
Happy Christmas y'all. Eat, drink, sleep, repeat as neccessary!
