ECN Forum Forums General Topics of the Trade General Discussion Area Toner and Probe Wire Tracing Tips

Hey guys I have always said that if you’re in the industry every electrician or technician should own a basic Tone and Probe for tracing wires. I get asked a lot of questions about how use one and would like to share with others some tips that can save them hours of time in the field.

I am willing to give a 33-864 IDEAL Tone and Probe to the first 5 guys who have a tip for using them.

If you’ve ever done much of it you know it is a little bit of an art form to trace wires in buildings. I would love to start a conversation about your favorite Tone and Probe tricks used for tracing wires. I would also like to know what else use them for?

I can start out with my favorite tip and one you won’t find in the instruction manuals. That is if you are down to 2 or 3 wires you feel is the correct one but still not sure. Use your body as a little extra resistance by wetting your fingertip and touch one of the wires. Then crank the volume up on the Probe and hold it closely to your ear. You should hear a very faint tone on the one that actually is the one you’re looking for. All other wires should give you no tone at all.

Give it a try it’s a good one!

Thanks Ron.
Sometimes i will use a length of THW 14 gauge wire to make an "antenna" and clip it to one of the leads of the receiver seems to help find in the wall route of the wire i am trying to trace.

Just as gee whiz info, how deep in the ground will this work?

Ron:
I have a old Progressive Electronics 200EP, and a Tempo 77HP/6A. The only 'trick' I ever did was to parallel two 9V batteries to the toner. It seemed to increase the signal.

It's interesting when I come upon a lot of abandoned data/comm on an inspection, that is tagged rather than removed by some LV guys. It's old & well used. I get it from the car, to 'see' if the tags match. Amazing how quick some data guys say.."we will remove it". Truth be they just randomly 'tagged' without any ring-out!

Little do they know that the speaker on the receiver is shot.

When I use them to trace power wires for a break or open I will trace from both directions. If the break appears in the same spot I pretty sure of where to cut the wall open and look for issues, often a hidden junction box.

Even though you can't normally use the toner and probe on a closed circuit, I still like to use the red led on my HP77/6A for continuity checks and to tell me when I've got the circuit open. Sometimes it's bad wiring or just light bulbs in a ceiling fixture with the wall switch in the on position or maybe a small appliance or table lamp plugged into a receptacle with its switch on. Once the toners red led light illuminates I can continue on probing the rest of the circuit.

I used to have 2 different tester for wires, one for dead wires and one for live wires. The testers was good for 120-277 volt. Sometimes when I had a broken wire, I would put the live on on the live end and the dead one on the other and it helped me to find the path between a house and a barn. Following the live side, the toner stopped by the side of a garden, and so did the dead side. I looked at the garden and saw a fence post. I asked the HO when he put in the fence and he said about 6 months ago, then I asked him when the power went out to the barn and he said, "Uhh 6 months ago." We dug down by the fence post and sure enough he hit the wire with the post.

I have an "older" Amprobe 6-600VAC Circuit Tracing Kit (older = purchased new in 1996).
The Transmitter pulses an Audio Frequency of apx.4.0kHz, with an Octave or Two on each side (1k, 2k, then 8k, 16k), at 250ms intervals (250ms on, then 250ms off, in a continuously repeating cadence).

The Audio Information is "Carried" on the 60Hz of the Branch Circuit under test (typical "Carrier Current" Modulation of the 60Hz Power Circuit).

Kit may be used on Energized or De-energized Circuits, with the Transmitter connected as follows:
a.: Directly for 300VAC and less Energized Circuitry,
b.: Through a 2:1 Step-Down Transformer, for Energized Circuits of >300VAC to 600VAC,
c.: Connected via 9VDC Drycell for De-energized Circuitry (no Loads connected to Circuit).

Trick #1:
(Beginning with the Receiver set for Tracing at the Conductor, first on the lowest sensitivity, moving to the highest sensitivity)

If the Energized Circuit under test contains either a Back-Up Battery Ballast, or Stand-Alone UPS, the Pulsed Audio Frequency will be noticeably distorted.
Half-Steps between Octaves are very noticeable, and the Amplitude of the Audio Fundamental 4.0Khz Tone is noticeably increased - as much as 140% the normal Amplitude.

When the Circuit does not resonate back through the Bus, into a Branch Circuit that has nearly similar XC, the Distorted Tone is strong only on the Circuit being tested.

When another Circuit is resonated, the signal strength is equally high on all effected Circuits.
To determine the tested Circuit, place the Receiver on the "Breakers" Selection, with the sensitivity set high.
Perform test on all Breakers with the Tone.
Turn Receiver 90° Left, then 90° Right.
Correct Circuit will remain high level throughout the turning, whereas the others will drop Amplitude.

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Trick #2:

Where Two or more Branch Circuits are showing similar Levels on the receiver (non-distorted signals), connect a suitable Load to the Circuit (at the Transmitter end), then look for that Load via Clamp-On type Ammeter.

Connecting an intermittent Load - such as a Flashing Lamp, will assist greatly if the Circuit being tested has randomly changing connected Loads.

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"Trick #3"...
(Not necessarily a Circuit Tracing tip, but still worth mentioning)

When using a High Input Z Voltmeter (i.e.: DVM) on Circuits with high levels of Capacitive Coupling effects (long L-N Circuits, or any types of Ungrounded Systems measured L-G), connect a Solenoid-Type Low Input Z Meter; such as a "Wiggy", "Vol-Test", or "Vol-Con", in Parallel with the Hi Z Meter, to Load the Circuit for an accurate reading.

I am sure there are several others, just can't think of any more right now!!!

--Scott (EE)

I have to say that Scott deserves an award for eloquence for the above detailed descriptions!!

Here's one every phone man knows...short the pair to kill the tone.
So you clip the toner leads onto the red and black conductors in a conduit that you think are the travelers for a 3-way circuit....there's some bleed-over tone on other black conductors in the three-gang box. Make sure the power is off and use a jumper to short each black to each red. When the tone goes dead, those are your wires.