eenie, meenie, minie, moe

dlochner · May 21, 2022

Clean the insulation. One of the black wires may be a very dirty red on.

twalker H260 · May 21, 2022

That looks like it may be the pigtails from a fixture. They are both regularly black because in an older incandescent fixture it didn’t matter what polarity the fixture had. If there is slack in the wires you could try and pull them up a bit to see if where they connect to the main wiring giving an indication of polarity. Of course if a PO re did the mast wiring all bets would be off as to colors. You could try checking wire color at the base of the mast as well to see what you have.

capta · May 21, 2022

Take this opportunity to use those wires as a messenger and replace the black wires with whatever colors you wish.

Tally Ho · May 21, 2022

if You have some wire, you can connect it to one of the 2 wires at the base of the mast, then lay it along the mast to the mid-mast wires…the use a DVM to check continuity on the 2 mid-mast wires…put some tape on both ends of the one that shows continuity.

Just need enough wire (almost any old stuff will work…thermostat, speaker, doorbell,) To get from the bast of the mast to the midpoint.

Otherwise, if the wire looks old, brittle, etc…do as @capta suggested, and run new, using the old wire to pull the new stuff through the mast.

Greg

ggrizzard · May 21, 2022

Be aware, on some older Hunters, the factory laid some wires that transited the liner/cabin top
with spots/wads of goo (probably butyl tape) to keep them in place. If so in your case,
be careful trying to use the existing wires as a messenger.

Sailor Sue · May 21, 2022

Any 12 volt battery should work. Can you pull your car up close enough to the mast, or use jumper wires to get it closer. Garden tractor, lawn mower, motorcycle battery....

Head Sail · May 21, 2022

Any continuity tester will help determine which is which. You may need a long test wire.

dlochner · May 21, 2022

Clean the insulation. One of the black wires may be a very dirty red on

Plymouth Sailor said:
Therein lies the problem. Which wire is positive! Can’t just designate and don’t have power to test since mast is laying on boat and not connected to electricity.

On a boat this old with suspect wiring, I'd replace the wire with 16 ga duplex or 16 ga triplex if you add a foredeck light. It is not that expensive, about $50 for a 100 foot roll.

jviss · May 21, 2022

Interesting replies. If it's for a mid-mast nav light, as you say, it doesn't matter - there is not polarity, it's just both sides of a resistive load. If you go to LED bulbs it will probably matter. But, in that case, you can just reverse the connections.

So, one wire will run to the switch or breaker that provides the positive potential, and the other will run to the ground - hopefully a bus bar. And that's all there is to it! No need to pull new wires, pull these out, etc., etc.

jviss · May 21, 2022

Tally Ho said:
if You have some wire, you can connect it to one of the 2 wires at the base of the mast, then lay it along the mast to the mid-mast wires…the use a DVM to check continuity on the 2 mid-mast wires…put some tape on both ends of the one that shows continuity.

Just need enough wire (almost any old stuff will work…thermostat, speaker, doorbell,) To get from the bast of the mast to the midpoint.

Otherwise, if the wire looks old, brittle, etc…do as @capta suggested, and run new, using the old wire to pull the new stuff through the mast.

Greg

Greg, what would he be checking for? If both wires are to either side of an incandescent bulb, there is no polarity!

jviss · May 21, 2022

Plymouth Sailor said:
Therein lies the problem. Which wire is positive! Can’t just designate and don’t have power to test since mast is laying on boat and not connected to electricity.

If it's an incandescent bulb, there is no polarity. One wire goes to ground, the other to +12V, and that's it. It will matter if you go to and LED bulb, but then you just reverse the connection.

dlochner · May 21, 2022

jviss said:
Greg, what would he be checking for? If both wires are to either side of an incandescent bulb, there is no polarity!

If you measure voltage on a DVM the voltage will read as a + voltage if the leads are correct, if they are backwards they will read as a - voltage.

Will Gilmore · May 21, 2022

Plymouth Sailor said:
Therein lies the problem. Which wire is positive! Can’t just designate and don’t have power to test since mast is laying on boat and not connected to electricity.

Connect the mast to ground. Use the mast as the ground on your multi-meter setup for a continuity test. Your meter should indicate no continuity if both ends of the wires are clear of the mast, and there are no exposed contacts inside the mast. The meter shouldn't do anything, just as if the two leads were not touching anything.

Next, connect one end of one wire to ground, the mast, in this case. Now test each wire at the other end for continuity to ground again. Only the wire touching the mast should show continuity to ground. Mark both ends of the wire you tested. Then disconnect the wire and repeat with the other wire to be sure it also has continuity.

This should give you the information you need and tell you if either wire has a break or shorts to the mast somewhere inside. No power supply needed.

-Will

PS: don't ask me how to use a multi-meter. I have used them, but not that often. I can't tell you anything you can't know from looking at the dial.

jviss · May 21, 2022

dlochner said:
If you measure voltage on a DVM the voltage will read as a + voltage if the leads are correct, if they are backwards they will read as a - voltage.

And, why does that matter?

All it's telling you that you have the DMV's positive lead on the side of the load that's connected to the plus side of the feed. It's neither correct nor incorrect. If you just swap the DVM leads it will change the negative reading to positive, and - it doesn't matter!

jviss · May 21, 2022

Will Gilmore said:
Connect the mast to ground. Use the mast as the ground on your multi-meter setup for a continuity test. Your meter should indicate no continuity if both ends of the wires are clear of the mast, and there are no exposed contacts inside the mast. The meter shouldn't do anything, just as if the two leads were not touching anything.

Next, connect one end of one wire to ground, the mast, in this case. Now test each wire at the other end for continuity to ground again. Only the wire touching the mast should show continuity to ground. Mark both ends of the wire you tested. Then disconnect the wire and repeat with the other wire to be sure it also has continuity.

This should give you the information you need and tell you if either wire has a break or shorts to the mast somewhere inside. No power supply needed.

-Will

PS: don't ask me how to use a multi-meter. I have used them, but not that often. I can't tell you anything you can't know from looking at the dial.

Common, accepted practice for wiring devices on a mast is that each resistive load (device) has two wires, one connected to ground, usually at the base of the mast, preferably a ground bus bar, and the other connected to the supply for that load, via a switch or breaker. Unless the load is sensitive to polarity as some (not all!) LED replacement bulbs are, it doesn't make a difference. And, if one doesn't come on, just swap the wires. Or swap the orientation of the bulb if it's a festoon type.

Tally Ho · May 21, 2022

jviss said:
Greg, what would he be checking for? If both wires are to either side of an incandescent bulb, there is no polarity!

Just continuity, so he can pick both ends of the same wire…which he seemed concerned about.

Greg