anchor light wiring question

[Tatheelrod22]

I bought a new anchor light to put at the mast head. When I removed the old one it had the basic positive negative coming up thru the mast. The new one however also has a ground wire. It's not going to be easy to connect it to something because then the bottom of the new light wouldn't be flush and sealed, which would cause leaks and problems. Can I just feed it down into the hole with the other two once connected? Should I just cut it off?

[smac999]

lots of anchor lights have 3 wires. but that's for a fwd / rear bulb separation. I have never seen a grounding wire.

and you sure it's not a ground wire and 2 pos light wires. front and rear?

[CaptTom]

Wait, are we talking about the negative wire, or a 3rd wire as a dedicated safety ground?

Most marine fixtures I've seen have a + and - wire. More + wires if there's more than one bulb (combined sidelights or combined anchor and steaming lights in one fixture.)

If the old one didn't have a negative wire, and relied on a "negative ground" through the mast, like a car, you can probably just put a screw into the mast and attach to that.

[a64pilot]

What brand / model of light?
Only function I can think of for a ground would be for an RF shield to help prevent radio noise, if that’s it, then the light will function without the ground being connected, might want to try a test to see.

[sailortype]

using the mast as the negative 'return' is a really bad idea. I read an account of a mast being destroyed by the owner using the mast as a negative for all the electrical equipment mounted on it. Auto electrics do not work on a boat.

[boeing1]

is this just a anchor light, the only ones I have installed only have two wires a pos and a grd, what does the installation instructions say that came with the light

[Cadence]

When all else fails read the instructions. If specified as a ground I would not worry about it. Tape it off to the other wires so it isn't flopping around.

[Terra Nova]

Originally Posted by Tatheelrod22

I bought a new anchor light to put at the mast head. When I removed the old one it had the basic positive negative coming up thru the mast...

Never heard of a positive negative.

[John_Trusty]

Originally Posted by Terra Nova

Never heard of a positive negative.

I suppose that you are kidding, and you know that OP meant a positive wire and a negative wire, but just shortened it. At least that's how I read it.

I've never seen a true safety 'ground' on any 12-volt appliance, as that's an AC thing. So what does it look like?

[skipmac]

Originally Posted by Cadence

When all else fails read the instructions.

Blasphemy!

[skipmac]

As others have noted, never heard of a 12V device with a positive, negative and ground other than maybe RF grounds on radios. For a light, never.

Are you sure this is one light only and not anchor and running light? Is it an LED bulb or bulbs? If LEDs three leads going to two separate LED bulbs can allow one pair of supply wires IE one positive and one negative, to turn on one or the other LED by alternating polarity of the supply voltage.

[Cadence]

Originally Posted by John_Trusty

I suppose that you are kidding, and you know that OP meant a positive wire and a negative wire, but just shortened it. At least that's how I read it.

I've never seen a true safety 'ground' on any 12-volt appliance, as that's an AC thing. So what does it look like?

As a wag, is it possible the ground is provided for installation on a wood, or for the wealthy carbon fiber mast, to be tied to a shroud providing a lightening ground. May save the wiring if the light housing is hit. I use those positive negative wires all the time.

[jkishel]

By chance, is the new light a tri-color mast head light/anchor light combination? This would have three leads; positive for the anchor light, positive for the tri-color and a common negative.

[skipmac]

Originally Posted by Terra Nova

Never heard of a positive negative.

Sure you have. Say you hear there's a fire at your marina, you call and the dockmaster says your boat is not on fire. That's a positive negative.

[Greg Mason]

I would agree that the wiring sounds like it is for a tri color light. A steaming light should never be masthead, and the only other logical use is a tri color/anchor light combo.