Identifying electrical loads at/on terminal strips.

JDCAVE · Mar 12, 2019

Are there “tricks” one can do with a multi meter to determine the ultimate breaker origin or load destination at the terminal strip? I’d rather not go through the process of disconnecting wires to see which loads aren’t working. The PO numbered the wires at the strip, but in most cases I have no idea the breaker of origin or the destination. Some suggestions would be appreciated.

Thanks! Jim

High Wire · Mar 12, 2019

Sure. There are lots of ways to do this.
One way is the hook the meter black lead to a good DC negative bus. Turn every breaker off. Then turn on one breaker (assuming you can turn it on and leave it on) and go down the terminal strip with the meter red lead looking for full battery voltage. When you find it, toggle the breaker to verify, then continue down the terminal strip. Write down what you find for you will not remember the details.
Repeat for the next breaker. It should only take a few minutes per breaker.

NWSeadog · Mar 12, 2019

Something I've used to track wires from the bridge down to the engine room is a "cable sniffer". You connect a tone generator between the wire you are interested in and ground then go to the other end with the receiver and start poking around until you find the wire with the tone on it. The receiver works through insulation and the closer you get to the wire the louder it is.

JDCAVE · Mar 12, 2019

Thank you so much! That makes sense! I wasn’t technically inclined and scared of the shop teachers at school, so I don’t remember much. If they could only see me now!

Jim

ranger58sb · Mar 12, 2019

If you have original schematics for the boat, you may be able to find wire sizes and color schedules for various circuits.

Even if you don't have schematics, you may be able to augment your tests with some color info, assuming KK wired a lot of that to ABYC-recommended color coding...

Might not be perfect, but might inform... or sometimes confirm... or at least help differentiate between A or B...

-Chris

Ventana · Mar 12, 2019

We use a toner (like the one NWSeadog posted) a lot at work to trace wire runs on the older boats. Mine is a Fluke Pro3000, not overly expensive but seems to work better than others for longer wire runs. There are pretty cheap options available for just a one time use. If the KK42 wiring diagrams would help I think I got a set with our boat and could take pictures to send to you. Just let me know and I'll dig them out of storage.

Maerin · Mar 12, 2019

High Wire said:
Sure. There are lots of ways to do this.
One way is the hook the meter black lead to a good DC negative bus. Turn every breaker off. Then turn on one breaker (assuming you can turn it on and leave it on) and go down the terminal strip with the meter red lead looking for full battery voltage. When you find it, toggle the breaker to verify, then continue down the terminal strip. Write down what you find for you will not remember the details.
Repeat for the next breaker. It should only take a few minutes per breaker.

^^^^ This^^^
Simple, reliable. I have a Fluke toner, it works, but it's not foolproof. It was around $80, IIRC. The DC voltmeter/DMM is much more straightforward. Label all that you identify. You WILL forget!!

koliver · Mar 12, 2019

ranger42c said:
If you have original schematics for the boat, you may be able to find wire sizes and color schedules for various circuits.

Even if you don't have schematics, you may be able to augment your tests with some color info, assuming KK wired a lot of that to ABYC-recommended color coding...

Might not be perfect, but might inform... or sometimes confirm... or at least help differentiate between A or B...

-Chris

LOL
Who has wiring schematics for their boat.
Of course you do if your boat was built in this millenium. Not we who have 80s Taiwan Trawlers.

Comodave · Mar 13, 2019

I had a 1978 F32 Trojan. I was able to order an owners manual from the Trojan website. It included a wiring diagram, original bill of sale and the usual owners info. It was awesome, unfortunately I can’t get anything like it for our President.

catalinajack · Mar 13, 2019

koliver said:
LOL
Who has wiring schematics for their boat.
Of course you do if your boat was built in this millenium. Not we who have 80s Taiwan Trawlers.

I have the wiring diagram for our 1983 DeFever 44.

FF · Mar 13, 2019

The wired alarm and other folks use a pad of stick on numbers .

I prefer to put the number on the item ,(radio, light whatever) and use the same number on its wires, line switch and circuit breaker.

When something doesn't work at O'dark 30, it makes trouble shooting a snap.

Its also useful to the next owner.

C lectric · Mar 13, 2019

I've used the pads of stick on letters and numbers but I then slip on a piece of clear heat shrink tubing.
I've dealt with too many slipped off stick on labels to want to deal with that anymore..

FF · Mar 14, 2019

"I've used the pads of stick on letters and numbers but I then slip on a piece of clear heat shrink tubing."

Yes, this is a good idea to seal on a second set of numbers a foot or so away.

That way the terminal ends can be replaces a few times and the wire marking remains useful.

OldDan1943 · Mar 14, 2019

Maerin said:
^^^^ This^^^
Simple, reliable. I have a Fluke toner, it works, but it's not foolproof. It was around $80, IIRC. The DC voltmeter/DMM is much more straightforward. Label all that you identify. You WILL forget!!

I assume you mean a Fox and Hound meter?

JDCAVE · Mar 14, 2019

Thanks for everyone’s thoughts and suggestions on my question. I will start by working with a multimeter and then I will get the tone metre to drill down a little further.

Jim

Identifying electrical loads at/on terminal strips.

JDCAVE

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NWSeadog

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ranger58sb

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