How can I determine which black wire is hot and which is neutral in an unlabeled light fixture without risking safety hazards?
Asked by Alison Olson 
2 months ago
Last Updated: October 25, 2024
So, someone gave me a light fixture but the two black wires aren’t labeled. Any tips on figuring out which one is hot and which is neutral? What could go wrong if I guess and get it wrong? Is it okay to just go for it and hope for the best?
Make sure to check if one has a ridge or is grooved. The smooth one will be hot and the grooved one will be neutral.
Is there perhaps a white stripe on one of them? Maybe it should have a white stripe on one…?
Is one of the wires textured with raised ridges? If yes, that’s likely the neutral wire.
Identify the neutral wire by locating the one with ribs on it.
Polarity isn’t important for a basic light fixture. While it’s useful during installation, it’s not critical. Just ensure a solid connection is made.
Edit: The non-insulated wire is for ground. I was specifically talking about the two insulated wires.
Remember the outer (screw) part of a light bulb should always be considered neutral.
The neutral wire is always distinguishable. Check for small ribs on one of the wires.
Use an ohm meter to identify the wire leading to the center of the light bulb socket. That’s your live wire.
Birren, maybe you’re just too sensible for this forum… you’re the voice of reason around here. The correct way should be the threaded pattern to the center. It will function in both ways, so why not do it right?
Yeah, , who cares if a little kid touches the threaded part and gets zapped?!
Exactly, …
If you examine it closely, you might notice a small rib on one of the wires which could be the ground, but it’s best to confirm with a quick oogle search 🤔
The ground should always be the bare wire. Come on, man. As a “top contributor,” please provide only accurate information.
The functionality won’t be affected…just remember that bare is ground or green.
You can wire the light either way as long as one wire is hot and the other is neutral. It will work regardless.
While it will function regardless of how it is connected, look for some small ‘ribs’ on one of the wires. That indicates the white wire.
The copper ground is essential, the others are not crucial
It’s not important
The way you wire it does make a difference. In a standard light socket, the outer ring is the neutral and the small contact at the bottom is the hot. The light will still function, but for safety, it’s better to orient it this way to reduce the risk of shock. If in doubt, use a continuity tester.
Rub them both and watch as a genie magically appears to grant you 3 wishes 😂
I see a rib on the wire to the left. That’s likely your neutral, which should be connected to the outer part of the lamp socket to avoid the risk of shock.
If you’re not sure, return it and get one with wires of different colors. By the way, I’m blonde.
It’s not important.
As others have mentioned, but just to reiterate. One wire will have ridges, while the other is smooth. The ridged wire is the neutral.
The ground wire is the final one among the options listed.
Why is it crucial to wire a basic lamp correctly even if it can function in either direction? https://www.youtube.com/watch?v=_Q5wYV3flKI
There is actually a good reason why it SHOULD be this way. Interestingly, it’s probably the same reason they put “do not drink” on bleach bottles.
Imagine the lamp was dropped and the bulb shattered. If it was wired incorrectly with the switch on the neutral side and also on the shell side of the socket. You might turn off the switch thinking it was safe to unscrew the remains of the bulb from the outside to avoid cutting your hand. SURPRISE you get shocked because the shell is still hot.
If you’re unsure, grab a continuity tester and check. Just touch the outer shell of the lamp socket and one wire with the meter. The one that shows continuity is your neutral.
The wire on the left side of the image serves as the Neutral wire
Touch the black wires. A squared wire indicates positive, while a rounded one indicates neutral (white). If you zoom in on the image, the wire furthest to the left is the live one.