Hi guys, a colleague called me to ask about what could be causing 8 LED GU10 lamps to blow when they are switched off. It started last week, all 8 LED lamps dead. They were all replaced and worked fine. Switch on again the next morning and all were dead again. A couple of 50W halogen lamps were fitted as a test, they were both dead the next morning. Only these lights are affected. The supply to the building is standard 3ph 4wire the loads are very very poorly balanced across the phases. Approximate total lighting load for the building is going to be around 220A.
Further information:
The lamps are installed in a display cabinet in a shop, they have been there for more than a couple off years with no faults. I do not know how old the first LED lamps were, but they were not fitted recently. The lamps are not cheap Chinese tat, the first LEDs were Megaman, the second were purchased from a local wholesaler. The wiring to the lights was poor and they have now been rewired. They are plugged in to the lighting circuit.
The shop has some key switches which allows a chunk of the lighting (and possibly other non essential loads) to be switched on/off at the start/end of the day. The majority of the lighting is 4' fluorescents with wound ballasts in the ceiling grid, along with a load of 70W metal halide spots.
On inspection of the failed halogen lamps, the filaments had just broken, there were no signs of the filament vaporising from a large blast that you might get from connection across 2 phases.
2 of us are going back Monday night to look again when we will be able to play with the lighting controls and trace the wiring as it is not clear where the supply is from.
This is not a fault I am familiar with, or have even heard of. If anyone has any ideas please let me know.
Echo
Further information:
The lamps are installed in a display cabinet in a shop, they have been there for more than a couple off years with no faults. I do not know how old the first LED lamps were, but they were not fitted recently. The lamps are not cheap Chinese tat, the first LEDs were Megaman, the second were purchased from a local wholesaler. The wiring to the lights was poor and they have now been rewired. They are plugged in to the lighting circuit.
The shop has some key switches which allows a chunk of the lighting (and possibly other non essential loads) to be switched on/off at the start/end of the day. The majority of the lighting is 4' fluorescents with wound ballasts in the ceiling grid, along with a load of 70W metal halide spots.
On inspection of the failed halogen lamps, the filaments had just broken, there were no signs of the filament vaporising from a large blast that you might get from connection across 2 phases.
2 of us are going back Monday night to look again when we will be able to play with the lighting controls and trace the wiring as it is not clear where the supply is from.
This is not a fault I am familiar with, or have even heard of. If anyone has any ideas please let me know.
Echo