Cable toner

When it comes to cable toners and tracers there are a few different types which can be deployed in different ways to achieve the end result
The first thing to consider is whether you need an open circuit or closed circuit tracer, on some you can operate them as open or closed circuit with a simple mode change
Having used cable tracers / toners since I got my first one back in the mid 1980's I have been experimenting on different ways of using them to find / locate faults. The first unit I bought was a 3M Scotchtrak unit it cost around £450 - £500 back in the 80's it only works as a closed circuit unit but will operate on voltages from 9v (PP3 battery) upto 600v so will allow it to work on dead and live circuits


A simple example of it's use back then (although not purchased for this fault) was an earth fault on an FP cable on a fire alarm, set it up to run from a 9v battery and connected it to the earth / metal foil sheath and to the conductors followed the tone on the cable to the point of the fault where the cable had been crushed and caused the short to earth

I also have a TeleTech toner / tracer which is more for telecom / data cable tracing although I have used it on mains cable faults as it will tone open circuit cables / faults

The big daddy is the Cat and Genny while it is designed more for tracing underground services there is no reason why it can't be used for tracing cables under floors and in ceiling voids

The first two are the most used bits of tracing kit I use and over the years I have adapted leads and connectors to suit different tracing needs

I have one of these: RS PRO Circuit Breaker Finder | RS Components - https://uk.rs-online.com/web/p/continuity-testers/1938690 that works fine, just thought a couple of croc clips on a lead may do what you want, the hand held bit does penetrate walls and CU's and seems quite accurate/sensitive as far as location is concerned.

Little update.... it does indeed work for tracing MI, managed to clamp one end and find them in a joint box 30m away. Went on L and N (worked using just 1 clamp but tone was louder with both)

One caveat is that with neighbouring circuits live there's audible interference making it impossible to hear the tone, this effected the longer runs, some shorter ones which I traced to confirm redundant worked fine.