Hi, I have a ceiling light that had 8 haolgen bulbs in it (two way switched). I have changed these all over to LED bulbs and now they seem to dimmly glow then the switch is off. I have checked all the wiring and everything seems ok. After reading a bit about LEd lighting, I switched one of the bulbs back to a halogen and all seems right in the world. It was oild appear that it is all because the neutral is not at zero volts. Any ideas of what I should check to make sure there is not a hidden problem in the old wiring (soon to be replaced), and or is there another way to fit this? Thanks.
Most likely a bit of induced voltage being picked up on the 2 way switching wiring, very common with led's.
Seneca Thanks. I have tried it with the two way switch. If I just have a terminal block on there, then it is fine. Add a length of 1.5mm cable (not even a single switch on the end of it) and the dim glow is there. Have have check the resistance of everything and it all seems fine. I have bypassed the switchdx live etc and it is still the same. Any other light fitting without LED'S is also ok, and as I said changing 1 led to a haolgen makes it worm correctly. It seems that I need some sink on there to get rid of voltage on the neutral line. Does this make sense?
Yes that does sound like what's needed, I reckon something like a 1 megohm resistor across the supply to the lamps might do the trick, not each lamp, just the feed where the supply goes to the lamp unit.
This is a known issue for LED lamps. The solution is fit a suppressor across the switch, or, replace one of the LED lamps with a tungsten filament. Both solutions work.
Some LED's have the suppressor built in and some don't. The problem fitting one in the switch is in the future it can end up being a duplicate of one in lamp. I had it with my two way switching and simply swapping make of LED cured the problem. With any AC supply the wires should be a set distance apart so the feed is balanced the inductance and capacitance cancel each other out. With high frequency this is a real problem you hear CB users referring to SWR voltage standing wave ratio. But with 50 Hertz it is not that much of a problem. But the method of running just the line to the switch means the feeder is not balanced. Using a suppressor is an attempt to balance the feeder as inside the suppressor is a capacitor. It is rather a Heath Robinson approach but it does work. As to if in the future we will modify our methods and start using the switch back box as the junction box instead of the ceiling rose I don't know? In some countries they already do use the switch back box but our method lends itself to emergency lights and ceiling fans so we will have to wait and see.
Yes, looping at the switch is my preferred method. It allows light fittings to be added very easily with only one wire in the fitting. It is especially useful for recessed downlights , too.
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