Voltage at light fitting that is turned off

[telectrix]

well, nick's just suggested 1 Meg. that's the trial and error part. try 1 Meg., and if it's no improvement, try a lower value. ( not too low, of course ). the combined R/C snubbers may well give a better result.

 

[BillyTheSparks]

ok so where do I get these things?

 

[topquark]

Clamp the cable and see what current has been induced, then you can work out the value. Discrete components from RS/Farnell/Maplins.

 

[BillyTheSparks]

Clamp the cable and see what current has been induced, then you can work out the value. Discrete components from RS/Farnell/Maplins.

Will try that when I'm next on site, Thank you.

 

[Knobhead]

This is repeat of a previous thread.
You could try either of these methods, no danger of resistors overheating.
View attachment 13020
View attachment 13019

 

[Farmelectrics]

ive noticed on here recently problems with leds staying on when switches are off not had any problems my self and fitted quite alot whats the general feeling of why there staying on just in case it happens to me look a fool if you cant tell customer why its happening

 

[Farmelectrics]

have these snubbers got to be fitted end of line or dosnt it matter

 

[BillyTheSparks]

Just trying to re-ignite this one as I'm back there tomorrow to have a go at it.

I'm going to start by taking all the LED lamps out of the circuit, and test again for the voltage. If it is still present (which I'm sure it will be) I'll then start taking the circuit apart.

The thing that is bugging me is that with ALL the light switches of the circuit off, I still get 74v at this particular down light fitting. And I also get approx 58v at the bathroom light fittings.

As said before all the neutrals are in Wago's, the wiring is new, all the conductors are meggering at >499 (I tested at 1000v to make sure). I've meggered the switches, taken the switches off and connected the wires into Wago's.

ANY ideas would be good just for me to try them. The more I think about it the more confuddled I get.

Many thanks for taking the time to read this.

 

[telectrix]

have these snubbers got to be fitted end of line or dosnt it matter

again, a bit of trial and error. don't think it matters where they go as long as it's across sl and n

 

[BillyTheSparks]

again, a bit of trial and error. don't think it matters where they go as long as it's across sl and n

I would like find the problem and fix it, rather than put in a 'solution' that might / might not sort it out.

 

[telectrix]

if it's induced voltage you won't be able to fix it as long as cables run together.

 

[BillyTheSparks]

Do you really think it could be an induced voltage of 74v?? and coming from the black strapper to the grey strapper but by-passing the earth wire?

 

[topquark]

Do you really think it could be an induced voltage of 74v?? and coming from the black strapper to the grey strapper but by-passing the earth wire?

Quite possibly. We're guessing you effectively have the equivalent to this as the overall circuit: http://cappels.org/dproj/simplest_LED_flasher/Simplest_LED_Flasher_Circuit.html with the 3 core for the two way lighting behaving as the capacitor.

The length of one of the strappers will dictate how high a value capacitor you in effect have (the longer the run the higher the capacity) and hence the PD present. You'll find the timing between flashes is a regular period (if only a long time between flashes).

The addition of a snubber resistance will increase the overall resistance to the point where there is insufficient current flow for the led lamps. It can eliminate it completely (but too high a resistance would mean no current flow at 230V either!).

So in this particular case probably not induced from an adjacent circuit, rather from that same circuit; so the only other way to eliminate it would be to run the strappers and common separately (separated by a greater distance, so then no capacitance build up).

 

[nickblake]

its great fun using low ohm resistors 100 ohm x 230 volts = one allmighty pong

 

[nickblake]

did have a problem with commercial hair dryers giving the user a shock when they un plugged them , the suppression capacator was across the incomming side of the switch so was holding charge after it was switched off an zapped any one when unplugged and they touched the pins easily rectified 20 hair dryers later relocated the capacator to the other side of the switch , and wrote to the manufacturers too