Broken wire to steaming light

[Tmacmi]

There is a broken wire to the steaming light.

Can you use an AC/DC clamp multimeter to find the exact place of the break? (presuming its somewhere between the entry into the boat and the panel)

[S/V Illusion]

No. You need current flow through the circuit to measure. As a wire is “broken”, no current is flowing in the circuit.

[Manateeman]

Hi Can you see where the wire exits the mast up top. Same question.
Describe or photo please. Will help for instructions to replace.
Happy trails to you.
Mark, currently mast building with manatee friends

[Tmacmi]

Originally Posted by Manateeman

Hi Can you see where the wire exits the mast up top. Same question.
Describe or photo please. Will help for instructions to replace.
Happy trails to you.
Mark, currently mast building with manatee friends

The light exits about 2/3 of the way up the mast. I thought the bulb had burnt out, so up I went in a bosun's chair to change.

The bulb isn't burnt out and all the other lights on that circuit work.

The socket is simply serviced by separate black and white wires.

They exit into the cabin at the compression post, run through a groove in the post, then through the bilge and then finally to the panel.

[JoeRobertJr]

Originally Posted by Tmacmi

They exit into the cabin at the compression post, run through a groove in the post, then through the bilge and then finally to the panel.

I would do some voltage readings to isolate. If you have access to the wires at the compression post, you could shave off a little insulation, take a voltage reading there, and then reinsulate. That would tell you whether the problem is towards the panel, or towards the light. Then repeat to narrow down the location.

I just replaced all the wiring in my boat from panel to mast and am about to start on the mast wiring. The old wiring had become too corroded.

[Bill O]

Originally Posted by Tmacmi

The light exits about 2/3 of the way up the mast. I thought the bulb had burnt out, so up I went in a bosun's chair to change.

The bulb isn't burnt out and all the other lights on that circuit work.

The socket is simply serviced by separate black and white wires.

They exit into the cabin at the compression post, run through a groove in the post, then through the bilge and then finally to the panel.

Did you check for V at the socket when you were up the mast? And you checked continuity on the bulb?

[Manateeman]

Hi You said all the other circuits are ok...I’m confused as to what you mean.
But ok...let’s try this. The above poster gave you good advice. Do you have a meter. Can you check the voltage anywhere on this wire. You can make a test light easily. Anyone here can tell you how.
Can you gently pull any wire out at the top...no force.it maybe easier to replace the wire. Any info on the light.
Manatee

[Tmacmi]

Originally Posted by Bill O

Did you check for V at the socket when you were up the mast? And you checked continuity on the bulb?

Unfortunately I did not have a multimeter with me when I went up the mast so didn't didn't check V. I did replace the existing bulb with a new one and there was no light. I also inspected the filament of the old bulb and it was fine.

Originally Posted by Manateeman

Hi You said all the other circuits are ok...I’m confused as to what you mean.
But ok...let’s try this. The above poster gave you good advice. Do you have a meter. Can you check the voltage anywhere on this wire. You can make a test light easily. Anyone here can tell you how.
Can you gently pull any wire out at the top...no force.it maybe easier to replace the wire. Any info on the light.
Manatee

When I say the other circuits were OK, what I should have said was the other lights that run off this circuit.

I have a multimeter. What I am trying to avoid is having to make cuts in the wire every so many feet.

Something like this but for DC current.

https://www.amazon.com/dp/B07TMDFG3W...xpY2s9dHJ1ZQ==

[JoeRobertJr]

Then, I would definitely start with Bill O's suggestion of going back up with a voltmeter and something to clean the contacts.

[Manateeman]

Hi. You can just stick a needle in the wire and seal it after with liquid tape or anything to keep the water out.
What kind of original wire...tinned marine? Can you bypass the panel and get some power up the mast. Maybe simple corrosion in the fixture and not the wire since this is more often the problem.
Manatee

[Bill O]

Originally Posted by Tmacmi

Unfortunately I did not have a multimeter with me when I went up the mast so didn't didn't check V. I did replace the existing bulb with a new one and there was no light. I also inspected the filament of the old bulb and it was fine.

If you are trying to eliminate all possible issues, make certain the bulbs are good. The new bulb was probably ok, but always check w/continuity because a visual can fool you. Similarly, save time w/checking fuses w/the same testing.
So the only way to do the testing is by finding where there is no power. I assume the steaming light has it's own separate switch. When you turn on that switch, are you getting power/V past the switch? If yes, next step. If no, trace power backwards on other side of switch.
If it was yes before, your next step is to go back up mast and check for V/power at the socket. If you have power on meter, may need to adjust or clean contacts. Bulb should work if good. Wiggle the bulb, does it go on/off (then contact issue). If still no power pull the unit off the mast (you are till up the mast) and check for power coming into the unit/socket from the wires.
If you have power at the wires, then bad unit or corrosion and replace or clean as needed.

[S/V Illusion]

Originally Posted by Tmacmi

Something like this but for DC current.

https://www.amazon.com/dp/B07TMDFG3W...xpY2s9dHJ1ZQ==

An equivalent does exist - a pulse generator and oscilloscope will tell you where the wire is broken and compute distance. -about $800 for a decent one.

The simplest, quickest and cheapest solution is pull the wire and replace it.

[CharlieJ]

@Tmacmi
You need a time domain reflectometer (TDR). It will test and report how far from the insertion point there is a short or an open. Call around to the good marine electricians in your area, one of them may have one.

[Cheechako]

Originally Posted by Manateeman

Hi. You can just stick a needle in the wire and seal it after with liquid tape or anything to keep the water out.
What kind of original wire...tinned marine? Can you bypass the panel and get some power up the mast. Maybe simple corrosion in the fixture and not the wire since this is more often the problem.
Manatee

Yeah, A simple 12v test light has a needle point on it. OP: Trace the wire. First see if there is voltage at the base of the mast. It could be anywhere. My guess is often something in the light fixture, so yeah, test for voltage up there. But you can test to the mast without that trouble first.

[Manateeman]

Captain Tmacmi. I’m sorry but I’m going to bow out of the thread. You can find some good basic books on boat electrical systems used and online. Add a simple meter, a stripper, a crimper, a box of heat shrink terminals and a roll or two of good wire. Then look at Blue Seas web pages and you can actually talk to experts about your problems. Probably you can find out how to run a new wire up the mast online...maybe with a video too. You can recoup the costs by fixing your own stuff, improving your boat and maybe helping others. It’s not difficult .
You will gain the satisfaction of learning a new skill and the happiness of being self reliant. You might burn your own boat down or kill yourself fooling with an inverter. Some following posts might tell you otherwise but if you can post on a computer and find and read web pages, I think you’ll do fine. Replace the wire.
Good advice already given. It’s boatbuilding not brain surgery. Have fun.
Happy trails to you.
Mark, just another simple manatee