Triplett Fox & Hound HotWire – PN: 3388 - Manual (Page 22)

Page 21
The Null Method
The concept of the “null” is illustrated in the following drawing.
When the HotWire Hound is passed perpendicularly over the wire with the HotWire Fox’s tracer signal, a
strong signal will be picked up on either side of the target wire, and a ‘null’ (dead spot) will appear right
over the wire. The null locates the wire within a few inches.
While it is possible to take special steps to promote the formation of a null, it is generally easiest to just
connect the HotWire Fox to the target circuit and see if it nulls by itself.
For example, connect the HotWire Fox to a wall outlet (the polarity is not important), trace the wire
through the wall by finding the null, and locate the target circuit breaker by finding the null over the
breaker. The sound from the HotWire Hound’s speaker and the brightness of it’s LED indicator will show
the location of the null. The following photos illustrate the process.