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Old 06-21-2021, 10:42 AM   #1
Seevee's Avatar
City: st pete
Vessel Model: 430 Mainship
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Cable/wire tracer

All of you electrical gurus....

I'd like to get feedback on tracing cables to make a wire diagram for the boat, and to eliminate old not used wires.

I've messed a bit with continuity checking, which has some value, but would like to get a good tracer and some techniques on how to use it effectively.


What is the best tracker for boats? (they seem to range from $30 up)
Can you identify cables if you can't disconnect them (one end).

And is it pretty easy to just try to follow a bundle that has you wire in it for the most part?

Good techniques and things to do, not do?

Would assume that one would want the cable unpowered, any reason otherwise?
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Old 06-21-2021, 11:24 AM   #2
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City: Southport, FL near Panama City
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I know tracers exist, but when tracing 12- and 120-volt wires sometimes bundled together on my boats, I have always relied on a physical trace and a VOM double check. I really should get smarter on this topic and will follow the thread with interest and the experts respond.
Rich Gano
FROLIC (2005 MainShip 30 Pilot II)
Panama City area
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Old 06-21-2021, 12:43 PM   #3
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City: Duvall, Wa. USA
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Many, many years ago I had a Summer job in a foreign country verifying wires were properly connected in a power plant under construction. We had sound powered headsets. I would put one wire from the headset on a ground and the other on the wire to be tested. All wires were numbered and we had a diagram that showed where each wire started and ended. I had a helper (or maybe I was the helper) and we would attach the headset to each end of the wire and talk to each other. We would then agree which wire to go to next. If we lost communication we would go to the last good wire. A setup like that might help tracing wires in a boat. And Seevee, good luck tracing all the wires in that 430. I'm not about to attempt that in mine.
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Old 06-21-2021, 03:28 PM   #4
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Following. I just ordered on of these to try and help sort through my own 45 year old wiring. But I don't fully know how to use it or what its limitations will be, so eager to hear from folks who know what they're doing.
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Old 06-21-2021, 05:00 PM   #5
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You are basically looking for a "fox and hound".
The meek will inherit the earth but, the brave will inherit the seas.
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Old 06-21-2021, 05:36 PM   #6
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City: Gloucester, MA
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I bought something similar

It certainly helps, but I wouldn't say it's a life saver. Getting a good signal onto the wire seems to be the trick, and it's tricky when the wire is hot or otherwise in use. It helped me trace some wires, but I still lost quite a few along the way.
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Old 06-21-2021, 06:19 PM   #7
City: Clearwater, Florida USA
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These are one of those devices where sometimes spending more gets more.

In the simplest situation, the circuit is complete (but powered off), and the device puts a small "ringing" current into the wire. It then senses the magnetic field using inductive coupling, amplifies it, and you hear and/or see a representation of it.

But, if the circuit isn't complete, there can't be a current flow. As a result, an inductive tester doesn't have an electromagnetic field to sense. To work on an open circuit, the tester needs to be electrostatic, in other words sense the "ringing" of the voltage (not the current). This is usually done with capacitive coupling.

Some circuit breaker testers work by imposing a "ringing" load on the live AC circuit, to add "noise" to the voltage that can then be sensed.

Good tracers have the ability to work with both electrostatic or electromagnetic fields, as well as ringing patterns that make noise rejection easier, and signal processing that effectively filters out the noise.

A lot of times when these devices don't seem to work, it is because they just aren't up to the job -- they expect a complete vs open circuit, or can't get past noise from electronic equipment or lighting circuits nearby, etc.

Also, in long runs, the wires can be parallel to each other and end up coupled that way. If the instrument isn't good enough to show the difference in strength, then one might need to remove the ground from the wire being traced or change the ground for the others, or do something else to break the coupling.

I've had good and bad "ringers" over the years. My current model, bought at Home Depot or Lowe's or Amazon (I forget which) doesn't work nearly as well as the one I had before it, which seemed to be able to get past any noise and operate electrostatically nearly as well as electromagnetically.
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Old 06-21-2021, 07:06 PM   #8
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City: st pete
Vessel Model: 430 Mainship
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We have a great start.

I think I should be looking at something more sophisticated than a fancy continuity checker.

But they have their value. I have used a son alert to beep at me when a broken wire made contact by wiggling it. This was with aircraft tracing down failures. But just tracing wires is a bit different.

Keep up the comments....

Porman, will send you the info if I get some good info, but bet your set up is totally different.
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