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baker.shawn

DIY light fixture is shocking

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3 Comments
by
baker.shawn
, 03-08-2012 at 08:41 PM (2145 Views)
the title basically says it all, I’ve only just discovered it today when i touched my fixtures heat sink and U-channel aluminum with wet hands...it wasn’t a strong shock but none the less this should not be happening

There are two posible sources of this stray voltage
  1. Where the wires from the drivers go through the sharp edge of the heat sink and in to my fixture its possible it cut the insulation.
  2. A while back I damaged one of my LED’s when I had to add longer wires, I accidently pulled off one of the contacts on a blue star and had to superglue my wire to remaining tiny tiny bit of the contact (solder wouldn’t work)
Does anyone know how I can use a multi meter to measure this stray voltage when i try and narrow the source

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Updated 03-09-2012 at 08:23 AM by baker.shawn

Categories
‎ Electrical , ‎ Questions - Need some input

Comments

  1. blennyman's Avatar
    Try grounding your fixture. Proper grounding is often overlooked in DIY projects and can be very dangerous depending on the currents.

    After proper grounding, some of your LEDs will likely stop lighting up and you will know right where you have a short. Don't leave them on for very long in this state because you can burn them up depending on where the short is...

    I think the most common problem I've seen with DIY LED builds is that the wire is touching the package of the LED in addition to being soldered on the pad.
  2. blennyman's Avatar
    Also - you should probe between GND and the various points on your LED strings. Each LED should have the same voltage across it and neighboring strings should be at the same relative voltage. If the heatsink isn't properly grounded as I suspect, and you have a short to the heatsink, the heatsink will end up being the same voltage as the node that shorted to it. If you then go back and ground the heatsink, the current will flow back to GND through the heatsink as the path of least resistance and the lights downstream of the short will likely not get enough current to light. Typically, I'll probe voltages. probe ground with the black probe and measure nodes with the red probe. If you want to measure stray current, you can do so by probing your heatsink directly in current mode. If you ground your heatsink, this should show 0A. (You can also measure stray current in your tank this way)
  3. baker.shawn's Avatar
    i just took some readings im getting 0A but about 4v