Discuss Voltage on light circuit when off in the Electrical Forum area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:   American Electrical Advice Forum

0.1μF is common, I can't see that a larger value would be needed for any reasonable amount of leakage, and the larger case would be harder to fit in a back box or wherever it's going.

BTW did you ever do any insulation tests on the switching as I recommended? It would be good to confirm that you are not simply concealing an actual fault.

Thanks. I will grab a bunch of 0.1μF RC snubbers.

I'm hopefully going back round this weekend. I will IR test then.
 
i have installed some down lights and have the problem of a light glow all the time when switched off. i understand induced voltage but dont have the problem on my other downlights so can only assume its a cheaper fitting.i have read about snubber and looks like a discharge device for the circuit. is this correct and what one is best to use?
 
Snubbers were originally intended for switching circuits to dampen the electrical noise generated by the arcing of contacts. They consist of a capacitor and resistor in series, the capacitor (typically around 0.1uF) passes a small current at 50Hz supply frequency but is quite low impedance to fast pulses, and the resistor (typically around 100R) serves to dampen any high frequency oscillations resulting from having inductance (motor, relay coil, etc) and capacitance together.

But now they are often put in parallel with one or more LED lights to provide an alternative path for the very small current that you can get passing via the capacitance of cables (in particular long runs for two-way switches, etc).

The part listed above from CPC is probably the best one to get, cheap enough and has insulated flexible wires that allow it to be fitted more easily in parallel with the LED light(s) (i.e. from L to N of one of the lights).
 
o
Snubbers were originally intended for switching circuits to dampen the electrical noise generated by the arcing of contacts. They consist of a capacitor and resistor in series, the capacitor (typically around 0.1uF) passes a small current at 50Hz supply frequency but is quite low impedance to fast pulses, and the resistor (typically around 100R) serves to dampen any high frequency oscillations resulting from having inductance (motor, relay coil, etc) and capacitance together.

But now they are often put in parallel with one or more LED lights to provide an alternative path for the very small current that you can get passing via the capacitance of cables (in particular long runs for two-way switches, etc).

The part listed above from CPC is probably the best one to get, cheap enough and has insulated flexible wires that allow it to be fitted more easily in parallel with the LED light(s) (i.e. from L to N of one of the lights).
oh just one thing supply frequency is 50hz but voltage is around 240v will that be the same specs or diff for .1uf and 100r
 
regarding neons. yesterday i fitted a LED bulkhead light for a client, fed from a IP 55 switch with neon "switch finder". the neon is connected across L and S/L so it lights up when switch is off. unfortunately, with the switch off, the lamp flickers, due to getting a reduced voltage via the neon. a quick vasectomy on the neon wires sorted that problem.
 
o

oh just one thing supply frequency is 50hz but voltage is around 240v will that be the same specs or diff for .1uf and 100r
The values are not critical.

Typically T&E is around 200pF/m or so capacitance, so 100m of cable is about 20nF

With 0.1uF = 100nF = 100,000pF shunting a high impedance load you would see around 1/6 of the supply voltage so around 40V which is (hopefully) below a value that will cause the LED driver to charge to the point it can light the LEDs themselves.

I doubt most installs have anything near 100m of cable for an individual light feed or strapper!
 

Reply to Voltage on light circuit when off in the Electrical Forum area at ElectriciansForums.net

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

Electrical Forum

Welcome to the Electrical Forum at ElectriciansForums.net. The friendliest electrical forum online. General electrical questions and answers can be found in the electrical forum.
This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock