I recently purchased these https://www.homedepot.com/p/Commercial-Electric-4-in-Matte-White-Integrated-LED-Recessed-Lighting-Trim-with-Adjustable-Color-Changing-Technology-4-Pack-NS01aA10ER1-259/303780853 to replace some old terrible lighting in our living room

And the new LEDs work in one room on one circuit but don't in this room The original light was an 50w 12v bulb with an mr16 connection: enter image description here

Original lights not taken out still work minus existing blown bulbs

I had no way of knowing the connection was different to other rooms as we couldn't even change bulb without ripping out the entire can (and ever bulb blows when we try to). While I do intended to replace the can with something more appropriate, I wanted to at least verify my LEDs work so (after I turned of the power) I cut the wires to the mr16 and tried joining the light wires with one of these to the connector that came with the bulbs enter image description here

But when I turn on the power with the led light it doesn't work. when I retest in the other room it still works I verified power is going to the light wires (other lights on same circuit continue to work)

Extra information: 20amp circuit A dimmer circuit but the LEDs I got support dimmers (and verified in another room) I am also not very knowledgeable on US electrics as I'm not originally from here so I didn't really know that mr16 was a thing until was pulled out

Can anyone help me understand why these are not working or what I might be doing wrong, I fully acknowledge that the way I am currently testing is probably not best practice or 100% safe, but as I mentioned above I would like to verify LEDs work on circuit before I proceed. Any recommendations on how I should do it would also be welcomed. If I can avoid it I would rather not get an electrician out for this.

If I can provide any more information let me know.

1 Answer 1


As far as I can tell from your question, you are supplying 12V to a light that expects 120V.

Not shocking that it doesn't work right.

If you have 50W 12V bulbs, somewhere in between the 120V supply and the 12V bulb is a transformer changing the voltage. You need to remove that from the path to your new lights.

If you want to test your new lights, just screw that adapter into any normal 120V lightbulb socket and plug your new lights into it, one by one, to verify that they work. Then replace the fixtures and wiring to get 120V to your new fixtures (or return them & get new "non-replacement" LED fixtures, since you are replacing fixtures anyway...depends what you want.)

Or, return those, and get 12V MR16 replacement bulbs, if you can figure out non-destructive opening of your existing cans (start a new question and take clear pictures if you want help with that part.)

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