FCU and Led under-counter light problem

[sponge23]

Hi all, having a problem on a job...
Using a switched FCU to control some LED under-cabinet strip lights. Customer reported that the lights were staying on after the FCU had been switched off. So I thought the FCU must be stuck in on position, so I replaced the unit.
Had a call from the customer today reporting the same problem.
Upon inspecting the original FCU, it appears to be working as it should. I.e. it isolates both live and neutral.

Any ideas?
Thanks in advance.

 

[telectrix]

i suspect capacitance . a snubber may help.

 

[sponge23]

Are you saying that there is a charge being stored somewhere then?

 

[telectrix]

possible. it's quite common for GU10 LEDs to stay faintly lit or flash after switch off. capacitance or induced voltage from adjacent live cables. a snubber draians the unwanted voltage away.

 

[sponge23]

Ok thanks, will try that. Just need to get one from somewhere now!

 

[telectrix]

try a 1 watt resistor, value around the 200Ω mark across the ELV feed to the strip

 

[Geordie Spark]

Hi all, having a problem on a job...
Using a switched FCU to control some LED under-cabinet strip lights. Customer reported that the lights were staying on after the FCU had been switched off. So I thought the FCU must be stuck in on position, so I replaced the unit.
Had a call from the customer today reporting the same problem.
Upon inspecting the original FCU, it appears to be working as it should. I.e. it isolates both live and neutral.

Any ideas?
Thanks in advance.

My idea is that it may have been wise to test the suspected "faulty" FCU BEFORE you went to the trouble and expense of replacing it.

 

[sponge23]

To Geordie Spark: I had this problem with an FCU before, admittedly an LAP one. So thought it would be prudent to take a replacement with me and just swap it.
The FCU in question this time is a BG one, which are usually alright.
Had no end of trouble with LAP bits in the past, so will not use anymore!

 

[micknew]

try a 1 watt resistor, value around the 200Ω mark across the ELV feed to the strip

Snubber's are usually capacitors not resistors.

 

[telectrix]

Snubber's are usually capacitors not resistors.

they're usually a R-C combination. anyway, as i advised the OP, the ELV side is DC, so a cap. would do diddly squat.