↑ Return to Tips & Tricks

Dangerous LED Light Set Power Supplies

30cm_meteor_tubes1Here’s a  cautionary tale that I thought I’d share with you.

I received some LED meteor tubes in today’s mail.

They are a set of 8 tubes and come with a small mains plugpack.

There are two tubes of each colour; red, green blue and amber.

Slightly annoying is that tubes of the same colour are next to each other.









30cm_meteor_tubes2The plugpack is marked as 4.2V 0.5A, but measuring it showed more like 6V with the lights disconnected.

While measuring the voltage, my finger touched one of the wires and I got a very unpleasant tingle.  Bastard!

At first I thought it was due to some low value suppression capacitors, but no…..











dodgy_led_psuOpening up the plugpack revealed the horror show here.

There is no isolation between the mains and the DC output – it’s a simple capacitive dropper circuit!

This may be fine for fully enclosed lights, but not for something like this where the end user is likely to extend the wiring.











Capacitive_PSU1This is the circuit of the cheap arse power supply.

Whoever thought this was suitable for Christmas lights should be shot.





So, if you do buy lights like these, immediately destroy the plugpack and instead run them from a proper power supply or approved plugpack.

These light sets are cheap and the meteor tubes themselves are fine for the price but again, DO NOT USE THE SUPPLIED PLUGPACK.