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#45093 11/19/04 05:29 PM
Joined: May 2004
Posts: 697
Dave55 Offline OP
I feel like a real fool on this one guys. I bought a tone generator a long time ago because I read you can use it to troubleshoot shorted BX. It has instructions for some other things, but I'm just not following it. It has a phone plug, red and black leads with clips, and a three position switch (Cont--Off--Tone).

What are these good for and how do you use them?


#45094 11/19/04 05:40 PM
Joined: Jan 2003
Posts: 4,391
Dave I use those all the time, they are great for identifying dead conductors.

However they are useless through metal raceways. I have no idea how you could find a fault in a shorted BX with one of these.

I would be interested to know if there is a way to do it.

On the other hand my Amprobe tracer when both the sender and receiver are set on high will read through metal raceways.


Bob Badger
Construction & Maintenance Electrician
#45095 11/19/04 06:08 PM
Joined: Jun 2003
Posts: 1,143
My Ideal ABS was able to follow a tone through RMC in my house - it's how I found the (plastered over) wall sconce boxes buried in 1943...

IIRC, finding a short in a BX run is clipping one wire to a conductor, the other to the armor... I think you have to figure out where it connects "down stream" and d/c it though, for this trick to work correctly.

#45096 11/19/04 06:11 PM
Joined: Aug 2001
Posts: 335
Their primary use is for phone/alarm wires. The second part of the set is the "wand". (the inductive receiver that picks up the tone) We put the tone on the wires and with the wand we can find the wire 500 feet away, in the middle of a bundle without having to physically follow the wire through all the ceilings. Tone won't go over shorted wires, thus the continuity setting. If the wire is shorted together we put the second clip on ground. The telco plug is paralleled with the clips. Plug it in a jack and you can pick up the tone at the punch block in a heartbeat.
I've never been able to make it work on shorted BX and if you ever put it on an energized (120v) wire ... you'll know you made a mistake.

#45097 11/20/04 12:57 AM
Joined: Dec 2003
Posts: 886
Isn't going to help with shorted BX or any shorted wire I'm afraid. You can use it to locate NM and possibly BX if you connect to the armor.

What it does is put an audio tone on the wiring, usually telecom wiring. The tone is then picked up with a probe or a buttset and is used to identify and locate the wire. Not much good without a probe.

This has been a standard with the telecom trade since the days of the buzzer.

As for the switch positions, Cont is for continuity. You will notice a LED somewhere on the thing. Put the switch in the Cont position and short the leads together. The LED should light red indicating continuity or a low resistance. This will tell you if whatever you are connected to is shorted and why you are not getting any tone on the wire.

When in the Tone position tone is applied to the leads and RJ plug for wire tracing. Also in this position, if the wire or jack has voltage on it the LED will light either red or green depending on the DC polarity and is a working line (remember this is telcom equipment). I don't remember what it will do with line voltage, probably light bright red. Most of these units will put tone on a telephone pair with battery. I wouldn't want to use it on a wire with line voltage on it however. It will warn you but wasn't designed for that use.

Off should be self explanatory.


[This message has been edited by hbiss (edited 11-20-2004).]

#45098 11/20/04 06:10 PM
Joined: Aug 2001
Posts: 7,520
As has already been said, we use these rgularly in telephone work. Some of the fancier sets will detect a shorted line automatically and light a "Short" LED on the unit upon connection.

#45099 11/20/04 10:37 PM
Joined: Oct 2004
Posts: 265
I've applied line voltage to these and they have not been damaged. But I don't think its a recommended practice.

#45100 11/24/04 06:25 AM
Joined: Jul 2003
Posts: 394
Does anybody else remember when they were known as a Ruptured Duck ?

#45101 12/01/04 02:30 PM
Joined: May 2004
Posts: 2
Junior Member
I usually use a set of ring out phones for that. I made a set a few years ago and people were always asking me where I got them. I started looking for more hand sets and whenever I would find a pair I would make a set and sell them at work.

[This message has been edited by Webmaster (edited 12-01-2004).]

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