Light fixture with switch on ground side?
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Comodave
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A lot of lights don’t follow the common color code. Who knows?
CompuNerd
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Yes, positive should be the switched leg. But as they say, electricity doesn't know what color the wires are, so the wire may have been reversed somewhere. Don't rely on what it "should" be; use a multimeter to verify which leg is positive.
If both wires are black, standard practice is to have some marking such as writing or ribbing that indicates the ground or neutral wire. Most sparkies will rely on the microscopic writing on the wire's insulation as the indicator. But when it comes to electricity, don't trust. Verify.
If both wires are black, standard practice is to have some marking such as writing or ribbing that indicates the ground or neutral wire. Most sparkies will rely on the microscopic writing on the wire's insulation as the indicator. But when it comes to electricity, don't trust. Verify.
SteveK
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You are not showing all connections, all wires. I do not see a red wire, just a red connector. The light is wired like most, it is up to the installer to know which wire to connect the positive and negative or hot & neutral with AC
FF
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"Why is this light fixture switched on ground?"
Because it wont kill you on low voltage , do it with 120v or 240v and you could die.
Because it wont kill you on low voltage , do it with 120v or 240v and you could die.
CompuNerd
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All true about low-voltage DC and high-voltage AC. Still recommend using wiring best practices rather than "hey, stuff works, who cares." Color coding provides guidance and safety for the next guy who comes along and has to work with the circuit. For example, if you have a parasitic load before the switch rather than after, it's tougher to troubleshoot which circuit has it and how to fix it.
You don't have to do a whole-boat rip-and-rewire but if you find something that either wasn't installed per code/ guidelines or was modified incorrectly by a previous owner, see what you can do to put it in proper shape.
You don't have to do a whole-boat rip-and-rewire but if you find something that either wasn't installed per code/ guidelines or was modified incorrectly by a previous owner, see what you can do to put it in proper shape.
porman
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I see you have a Camano Troll. On our 2005 Camano I replaced all the cabin light bulbs with LED's. The lights did not work. I found the fixtures were wired with positive to the base of the bulb instead of negative to the base. Swapped the wires and everything worked.
psneeld
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The wiring for daisy chained light in older boats....there is no positive or negative until hooked up... I have seen different fixtures in line wired alternately because it didn't matter for DC, incandescent bulbs...and it didn't matter where you broke or made the circuit.
Best practice???? No..but it DIDN'T matter in the big scheme of things and I would bet good money nobody got hurt or burned a boat down because of this.
Do it better if rewiring... if replacing just a couple fixtures or switches...man I wouldn't sweat it.
Best practice???? No..but it DIDN'T matter in the big scheme of things and I would bet good money nobody got hurt or burned a boat down because of this.
Do it better if rewiring... if replacing just a couple fixtures or switches...man I wouldn't sweat it.
OP
OP
jhance
Senior Member
I have replaced two lights that look to be original from the manufacturer. Both lights were switched on the negative leg (switch attached to the black boat wiring). There must have been a reason for this, I would think, so I just replaced the lights as they were installed. But new lights have this same phenomenon. Why are black wires coming into and out of the switch on the light fixture if you are supposed to switch the positive (red) side? Black to black, red to red, right?
Do the lights only have black wires and no red wire?
The positive lead should be switched. It is preferred to be colored red on a 12v DC circuit. The light may not have a positive or negative side so it has 2 black leads and doesn't care what gets connected to where, unless the leads are polarized and both black then the positive lead will have writing and or white hash marks on it.
Always test and verify. I may use a 4 conductor cable to run two 12v DC circuits. One is red +, black - and the other may be white +, green - with the darker color of the pair negative. Depends what you are doing and what you have available.
The positive lead should be switched. It is preferred to be colored red on a 12v DC circuit. The light may not have a positive or negative side so it has 2 black leads and doesn't care what gets connected to where, unless the leads are polarized and both black then the positive lead will have writing and or white hash marks on it.
Always test and verify. I may use a 4 conductor cable to run two 12v DC circuits. One is red +, black - and the other may be white +, green - with the darker color of the pair negative. Depends what you are doing and what you have available.
OP
OP
jhance
Senior Member
This is the new fixture. I understand that the positive side is generally the side you want to switch, but that would mean I need to connect the red wire from the fixture to the black wire from the boat, and the black wire from the fixture to the blue wire from the boat. Everything in my being is telling me not to do that!
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HTurner
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You really should have a Volt-Ohm meter (VOM) and measure out what is positive and what is negative.
RT Firefly
Enigma
Greetings,
Mr. j. I share your anality (word?). What I would do is re-colour the light wires. Buy some coloured heat shrink and apply as needed. Put some red on the black fixture wire and some black on the red..
https://www.walmart.com/ip/8-Sizes-Professional-Colorful-Polyolefin-2-1-Halogen-Free-Heat-Shrink-Tubing-Tube-Sleeving-1-0-14-0/209146849?wmlspartner=wlpa&selectedSellerId=101043446&adid=22222222222425323621&wmlspartner=wmtlabs&wl0=e&wl1=s&wl2=c&wl3=74766941315953&wl4=pla-4578366475203283&wl5=&wl6=&wl7=&wl10=Walmart&wl11=Online&wl12=209146849_10001062821&wl14=colored%20heat%20shrink%20tubing%20harbor%20freight&veh=sem&msclkid=64aae6075eba1381d47187e0079761f3&gclid=64aae6075eba1381d47187e0079761f3&gclsrc=3p.ds
Edit: Just read Mr. HT's excellent suggestion. Re-colour as to your discovery.
Mr. j. I share your anality (word?). What I would do is re-colour the light wires. Buy some coloured heat shrink and apply as needed. Put some red on the black fixture wire and some black on the red..
https://www.walmart.com/ip/8-Sizes-Professional-Colorful-Polyolefin-2-1-Halogen-Free-Heat-Shrink-Tubing-Tube-Sleeving-1-0-14-0/209146849?wmlspartner=wlpa&selectedSellerId=101043446&adid=22222222222425323621&wmlspartner=wmtlabs&wl0=e&wl1=s&wl2=c&wl3=74766941315953&wl4=pla-4578366475203283&wl5=&wl6=&wl7=&wl10=Walmart&wl11=Online&wl12=209146849_10001062821&wl14=colored%20heat%20shrink%20tubing%20harbor%20freight&veh=sem&msclkid=64aae6075eba1381d47187e0079761f3&gclid=64aae6075eba1381d47187e0079761f3&gclsrc=3p.ds
Edit: Just read Mr. HT's excellent suggestion. Re-colour as to your discovery.
Last edited:
SteveK
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Once found an entire house wired by owner where neutral AC was switched. I was changing a light fixture when I got a charge out of it.
At the time I was told the owner worked with circuit boards which are always switched after to reduce arching. Is that true?
Perhaps a new hire came from same background when this boat was built
At the time I was told the owner worked with circuit boards which are always switched after to reduce arching. Is that true?
Perhaps a new hire came from same background when this boat was built
Greg S
Senior Member
It’s a boat, not a car or a AC powered home. The colours are OFTEN different than you would expect. Black will be the colour of the cables for negative at the battery’s. In the distribution on the rest of the boat, you may (will) find it to be different.
ABYC has a standard but they are a relatively new player. Anybody on here have access to the ABYC standard for circuit wiring colours?
ABYC has a standard but they are a relatively new player. Anybody on here have access to the ABYC standard for circuit wiring colours?
SteveK
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I heard they changed black negative to yellow negative to avoid this type of confusion.
If I'm not mistaken switching ground in autos is fairly common... at least it used to be.
It is handy where a light is switched from multiple locations.
One power lead and a chassis ground is generally close by.
It is handy where a light is switched from multiple locations.
One power lead and a chassis ground is generally close by.
FF
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Some folks are not pleased with the color of LED lights.
We have overhead lights that have two contacts . By installing an auto bulbs with 2 filaments and adding a switch 3 levels of brightness is done .
WE installed a pull switch for the dim element as it is easily located/understood by a guest .
We have overhead lights that have two contacts . By installing an auto bulbs with 2 filaments and adding a switch 3 levels of brightness is done .
WE installed a pull switch for the dim element as it is easily located/understood by a guest .
Greg S
Senior Member
Interior lights on most vehicles were(are?) done this way. The switch at the door goes to ground. Some vehicles (Chrysler for instance) have the positive going to the horn and the horn switch grounds it. Some radiator coolant fans are powered by positive and the switch grounds them. The variable speed heater fan in one of my cars is switched on the negative side.
I put my money , 25 cents, on the positive wire being a different colour than the OP expects.
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Greg S
Senior Member
There is a perfect example. Yellow is going to be found as the negative, as per the note at the bottom of the page.
I’ve also seen green as negative.
I’ve also seen almost all one colour used with numbers on each end.
led light color used to be awful. everything was so pale in the light, not like the nice golden hue from incandescent.
fortunately, there are lots of color values to choose from. i use a nice warm white color and it's perfect. not quite as bright, but a really nice color. huge difference in amp draw.
