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Hi, here's a good one - replaced 15 E-lights recently, (tube type replaced with Newlec led type), and noticed one of the old outside Thorn 2D E-lights was on when driving past a few days later. The Thorn lights are all up to spec and function as they should. Went to investigate and it seems that some residual voltage on the switched / maintained line is triggering one light to come on. I connected the switched lines to two of the inside lights and now they stay on but the outside light is off. Enough residual voltage absorbed by the interior lights prevents outside light triggering.
It seems that the voltage threshold for the maintained input is set so low that it can trigger switching from induced voltage. Someone else has had the same problem here I think as there are a few disconnected exit lights that should be on the exit light switch. The system is 19 E-lights in two banks across the whole building. Four outside and the rest indoors. The exit routes E-lights are supposed to be switched / maintained but only one outside light was left connected. Someone has disconnected the faulty ones previously. The wiring system is only a few years old and has been done to a good standard. The earth lines are present to all the E-lights so I would have thought that the residual voltage would be drained sufficiently to avoid nuisance operation.
Still with me? So, the switched live lines show correct switching when operating the exit light switch. There is a very small voltage present on these lines however when the switch is off that is enough to trigger the lights.
There is a split phase supply to the main grid switch position for all the lights. Could it be that the induced voltage in the grid switch enclosure is high enough to cause this? (415 between phases in a small enclosure feeding two single phase systems). The lighting system is all 240V, it has just been wired so the system is supplied from two phases.
Could it be that the main earth impedance for the building is high and causing stray currents? I will go back and check this.
I am considering fitting resistors / filter capacitors to the switched live inputs to see if that cures the problem.
Anyone else had a similar experience? Any clues most welcome.
I have had to leave the switched lines disconnected at the lights themselves as disconnecting the exit lights switch has no effect, (other than disabling the function of the switch).
All the lights perform as they should under test. The charging indicators are showing ok.
I love my job really. Honest.
It seems that the voltage threshold for the maintained input is set so low that it can trigger switching from induced voltage. Someone else has had the same problem here I think as there are a few disconnected exit lights that should be on the exit light switch. The system is 19 E-lights in two banks across the whole building. Four outside and the rest indoors. The exit routes E-lights are supposed to be switched / maintained but only one outside light was left connected. Someone has disconnected the faulty ones previously. The wiring system is only a few years old and has been done to a good standard. The earth lines are present to all the E-lights so I would have thought that the residual voltage would be drained sufficiently to avoid nuisance operation.
Still with me? So, the switched live lines show correct switching when operating the exit light switch. There is a very small voltage present on these lines however when the switch is off that is enough to trigger the lights.
There is a split phase supply to the main grid switch position for all the lights. Could it be that the induced voltage in the grid switch enclosure is high enough to cause this? (415 between phases in a small enclosure feeding two single phase systems). The lighting system is all 240V, it has just been wired so the system is supplied from two phases.
Could it be that the main earth impedance for the building is high and causing stray currents? I will go back and check this.
I am considering fitting resistors / filter capacitors to the switched live inputs to see if that cures the problem.
Anyone else had a similar experience? Any clues most welcome.
I have had to leave the switched lines disconnected at the lights themselves as disconnecting the exit lights switch has no effect, (other than disabling the function of the switch).
All the lights perform as they should under test. The charging indicators are showing ok.
I love my job really. Honest.