Accessing wiring in masthead with mast up

[geoffschultz]

I'm in Guaymas, Mexico and am just about ready to head out cruising. I just checked the LED anchor and incandescent steaming lights and found that neither of them work. They share a common ground and there's power at the base, but I don't see any resistance between ground and + through the steaming light. Atop the mast I checked the incandescent bulb and found the filament to be intact and no corrosion on the contacts.

The connections to the power cable are under the mast head cap and there's no way to access them without removing the mast head, which I can't do with me suspended from the halyard. Does anyone have any great ideas as how I can work on the wiring short of bringing in a crane from somewhere?

-- Geoff

 

[Nodak7]

I'm in Guaymas, Mexico and am just about ready to head out cruising. I just checked the LED anchor and incandescent steaming lights and found that neither of them work. They share a common ground and there's power at the base, but I don't see any resistance between ground and + through the steaming light. Atop the mast I checked the incandescent bulb and found the filament to be intact and no corrosion on the contacts.

The connections to the power cable are under the mast head cap and there's no way to access them without removing the mast head, which I can't do with me suspended from the halyard. Does anyone have any great ideas as how I can work on the wiring short of bringing in a crane from somewhere?

-- Geoff

Geoff, take a volt meter up top. Remove the bulb. Turn to lights on and check to see if you have any voltage between the mast and the positive. If you do then your ground is open. If you don't then the hot wire is open. If you do show voltage then check the positive and negative inside the bulb receptacle. If you show voltage then the bulb is bad. With the bulb out you might also want to check the connections in there for corrosion. Clean them and then recheck.

If something is open you might see if there is screws holding the lamp fixture to the top. If so you might be able to undo the fixture and pull it out to see the connections. It seems odd that they would make it so you had to pull the head off to get to the lamp connections.

Good luck! I wish I were there with you! LOL

 

[geoffschultz]

The problem is in the ground as it's the common wire between the two lights. I can see continuity across the incandescent bulb, but don't see anything at the base of the mast.

I'm just trying to find a way to levitate myself and work on the mast head...

-- Geoff

 

[Benny17441]

The steaming light and anchor light need to be able to be used separately so you should have two power (+) wires each going to each fixture and one or common ground (-) line for both. Since neither light comes on I would suspect the fault lies between the mast base and the steaming light. I would release the steaming light fixture from the mast and run a properly grounded wire on the outside of the mast and connect to the ground of the fixture. If my reasoning is correct both lights should come on. If only the anchor light comes on then there is a problem with the masthead fixture. If both lights come on then you have located the problem and it is just a matter of dropping a new ground wire down inside the mast from the steaming light opening.

 

[Bill Roosa]

Is the ground good on the boat side of the circuit?
Turn the light on and probe the hot wire and the common ground both on the boat side and see if there is battery voltage.
I'm not convinced that you have a mast wiring problem yet. Both lights going out at the same time means something common to both is not working. You said there is no (0 not infinite???) resistance between the base + to the steaming light and the common ground wire. Is it no or infinite? The breaker would pop if there are 0 ohms so I'm thinking what you meant was a very high resistance. That would mean an open in the ground down from the steaming light.
Without knowing the exact placement of the ground connection that makes it a “common” it is hard to tell. I’ve seen boats with the ground running from mast head to steaming/spreader lights and they all connect there (a bad design BTW) and I’ve seen them where all the grounds are separate till they get to the mast base and then they join together (hopefully below deck but I’ve seen them be above deck at the mast base also (also a bad design))
Do you know which configuration you have?

 

[geoffschultz]

I miss phrased my resistance statement. From the base of the mast I see an open circuit. Last night I re-did the crimp connection to the ground going up the mast, but there was no change.

The reason that there's only 3 wires is that originally the anchor/steaming light was a single unit from Perko that had 2 separate bulbs in it with 3 wires. You'd turn on the forward one for a steaming light and both for and anchor light. Then I added a LED based anchor light and had to use a single ground wire for both.

What I've figured out is that there's a heave duty ground wire going to the mast head. I should be able to get a wire on to a screw at the top and use that as the ground. Of course this is much easier said than done...

-- Geoff

 

[Bill Roosa]

OK, so I'm still wondering if the ground on the boat side is good.
If that checks out then I think you daignosed the problem, an open in the ground.
I find working at the mast head easier if you fassion some stuips from some spair line. one end attaches to the mast head or halyard and the other has a loop for your foot. make two and adjust the length so your head is above the mast head. If you attach the sturips on the same side as you stand it provides more stability.