1. Home
  2. ⏚ Electrical Engineering
  3. How to test Christmas Light voltage withstand quality?

How to test Christmas Light voltage withstand quality?

Hi guys and gals,

My background is Electrical Engineering and I worked as a test engineer for a while. However I've run into a few problems with my side business of importing Christmas lights.

I've got containers of these beautiful LED christmas lights which are CE and GS certified and rated for EUROPEAN outlet supply voltage of

230V at 50Hz.

The problem is that when plugged in, a FEW of the LED lights start burning out the plastic casing around them because the LED gets too hot.

How do I test my product to see if it's functioning at what it rated at? Are the LEDs bad?

Basically, I would like to know if the lights are bad (LED burning too much wattage) or are the LED working properly but the certifications are wrong?

I mean, during proper function, these LED lights SHOULD NOT burn so hot that it melts the plastic PCV casing.

Thanks a bunch, Christian

Reply to
christian
Loading thread data ...

Hmmm, what are you experienced at testing then ? Have you had anything to do with LED's, not an unusual device for EE type chappies. In fact many more humble tradespeople can determine the curent flow and even decide if it's above the LED specs.

Cheers ......... Rheilly P

Where theres a will, I want to be in it.

Reply to
Rheilly Phoull

The design appears defective.

I would suspect that groups of individual LEDs have been wired in parallel - a serious mistake to make as it could easily result in unequal current sharing and overloading of one LED in the group.

It may be that the design specified LEDs with built in current limiting

- but the manufacturer fitted cheaper, standard, LEDs without this feature.

AFAIK, CE and GS certification wouldn't examine in detail the choice of components on the very low voltage side of an insulation barrier.

It is highly unlikely that the LEDs are "bad" - but they may not be the correct LEDs that should have been used.

Trace the wiring, determine if individual LEDs are wired in parallel with each other. If so, take an individual LED and see if it current-limits with increasing voltage. If not, you have the answer.

Reply to
Palindr☻me

plugged in to what? 208 V 60 Hz ? 220?

a FEW of the LED lights start

not a good thing :)

maybe the plastic housings are the problem. too low a melting point.

get a 230 V 50 Hz inverter that runs from batteries?

correct

as LEDs run on DC there must be a power supply for the lights. whether this is a simple 1/2 wave rectifier or something more elaborate you must determine.

if the lights are too bright, in addition to excess heat the service life will be greatly reduced.

Reply to
TimPerry

sci.engr.lighting may have the answer. There are some very good lighting specialists there.

Reply to
Warax

Added sci.engr.electrical.compliance, from sci.engr.lighting

Going to guess that there may be raised eyebrows at validity of the CE/GS sticky lables.

LED sets that familiar with usually use standard 5mm epoxy encased LEDS rated at your nominal 20mA. U.S. style ForeverBright with an over-moulded shape and run as one long series string on 120V. Most UK,

240V, LED Christmas lights tend to be either battery operated or from a wall wart 24V DC supply. Some LED products wired in series strings with resistor in series, physically large resistor....

Unless the LEDs used are very high power, 1W+, guessing heat isnt coming from LED. 5mm LEDs can generate enough heat to distintegrate themselves in extreme cases non passively,not a big bang, but still some shrapnel To heat the plastic casing sounds more like an inadequately rated resistor for the task.

Perhaps the OP could explain the sypmtoms in more detail?

Adam

Reply to
Adam Aglionby

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.