CHAPTER
5 Temperature Monitoring as a Diagnostic Aid
T
he primary by-product of excessive electrical resistance is heat, which can be an
electrical system’s worst enemy. Along with causing early failures of expensive elec-
trical and electronic equipment, excessive heat can cause fires. A recent study con-
ducted by BoatU.S. determined that 55% of all boat fires are caused by faulty electrical
installations. It’s no wonder the ABYC addresses excessive electrical resistance and heat
buildup in several standards dealing with electrical installations and equipment.
Since heat is such an important issue, a few years ago I decided that I should measure
it in electrical systems, just as I had always done with engine cooling systems and refriger-
ation systems. Enter the heat sensor or heat-sensing gun, which is basically a handheld
infrared thermometer. The unit uses an invisible infrared beam to sense the energy that is
emitted, transmitted, or reflected from an object and translates that data into temperature. It
also has a laser beam for aiming and an internal battery. They range in price from $30 to $150.
Because the laser and infrared beams can go where you cannot go, or perhaps may not
want to go (remember we’re dealing with excessive heat), it is a handy device for locating a
number of potential problems:- loose cable termination points
- damaged or corroded terminals
- undersized wiring
- faulty relays and switches (these will run hotter than normal if they have bad internal
connections)
Model 42500, Extech Instruments, http://www.extech.com (replaces model 42520)
Model TG-600, Greenlee, http://www.greenlee.com
60 series, Fluke, http://www.fluke.com
Model T-7350, Professional Equipment, http://www.professionalequipment.com
Model 22-325, RadioShack, http://www.radioshack.comINFRARED HEAT SENSORSCopyright © 2007 by Edwin R. Sherman. Click here for terms of use.