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Currently installing a replacement power supply for my old 24V LED Strip lights in the kitchen. Almost got it fully connected, but on the DC end I hit a snag:

I made a small error in my wiring reference, the picture of the cables running from the PSU to the LEDs is from an angle that does not tell me which of the white cables is the V+, and which is the V-. I only noticed this after I disconnected the old PSU from the connectors. The new PSU is NOT the unknown, it has clear labels.

So in short: What polarity does White cable with a Black Stripe running along its side usually indicate?

I referred to What do solid/striped lines on a wire indicate? but this in-question had black wire with white stripes.

I have a suspicion that it is Positive, due to white cable with yellow or red stripe being the positive, but I am unsure because its black stripe.

EDIT: Adding to the issue:

A potential Answer would always be use a "multimeter": However how do you use a multimeter to distinguish is for an input cable? A multimeter doesn't really output power to power the strip.

Second problem is that the wires in the PCB do not seem to be the wires I am getting on the other side. So would the best course of action be disassemble half the kitchen to rewire everything?

MAL
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  • I suppose you should be able to find out with a multimeter? – jcaron Jan 02 '19 at 12:45
  • Or upload a picture that shows how the traces and other components on the PCB are placed (assuming it's mounted on a PCB). There's no fail-safe way to determine the polarity just by looking at the color of the wires. – MartinF Jan 02 '19 at 12:47
  • Your question really is a duplicate of the question you linked. If you read carefully you will see this, and the best answer is the same as that suggested by @jcaron – Elliot Alderson Jan 02 '19 at 12:49
  • @ElliotAlderson how exactly would one go about using a multimeter to test something that does not output power and only receives power? The second problem is everything else is obfuscated, since the wireing is done by the previous owner of the apartment. This includes: the wires in the LED are not the same wire as the wire that is near the PSU, meaning somewhere along the line there is a crimp. – MAL Jan 02 '19 at 12:49
  • @MAL it was my impression from your question that those wires were still attached to the PSU but disconnected from the rest of the circuit, is that not the case? – jcaron Jan 02 '19 at 12:53
  • @jcaron no, the psu is separate entity and is not the unknown: I know which is which on the psu as it has clear red and black scheme,as labeled nicely what goes where. i dont know what is what from the stripe, which cabling happens to be white and white + black stripe.. – MAL Jan 02 '19 at 12:58
  • Your original question did suggest that the cables were still connected to the power supply. The important point from the duplicate question's answers is that **there is no rule** that you can count on, so there is no definitive answer to your question. You will need to get access to the LEDs. – Elliot Alderson Jan 02 '19 at 13:10
  • If the wiring was modified by the homeowner then it is even less likely to follow any common practice. Get access to an LED and measure continuity to the striped and stripeless wires, then you will know how they are connected. – Elliot Alderson Jan 02 '19 at 13:12
  • If the LED strip lights were designed well, they would simply not illuminate when the polarity is wrong, and no harm would be done. – Andrew Morton Jan 02 '19 at 14:22
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    If you've lost track of which connections on the LED strip are which, you'll have to reverse-engineer it in order to figure it out. – Dave Tweed Jan 02 '19 at 14:26
  • Ended up just spending the entire day dismantling everything to find out the actual configuration: including moving an integrated fridge just to get to the LED strip end, just to get to the LED PCB out. It was reverse of how I was expecting it to be. re-Soldered it correctly and sorted it out and labeled the wires just to be sure for the future, was way too much work for what I expected would have been a routine thing normally. – MAL Jan 03 '19 at 14:42

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