Infrared Thermometers

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wireman3736

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Just some questions on the use of thermometers, I recently purchased a fluke 63 I thought would be handy in trouble shooting. I just wondered how to determine when there is an actual problem on equipment or if the equipment may be operating at a higher temp because it is carrying the full load that it was intended for. Correct me if I'm wrong but the marking on equipment means such as 40c on a standard plug in circuit breaker is the max. operating temp above ambient temperature. You can scan through a circuit breaker panel and find a breaker that is running hotter then the others that has a load on it but how would you determine when in fact it is an actual problem or potential problem, same in a main lug panel or switch, if one leg is drawing more then the other you can see one warmer then the other but when is it a problem? any info on this would be appreciated. Thanks Stan
 
I use them for comparitve readings of single circuits.
A branch circuit to a motor should have temperature readings very close to any other connection in the circuit at the point they are taken. Scan the top of the starter. Temp at L1, L2, L3 should be the same or very close. Now compare each connection or contact point on down with all the others. Temps at each of these points should be the same or close to the others. Scanning circuits of different ampacities and conductor sizes and expecting an identical temperature is not realistic.

The two small handheld that I have only generate a temperature reading and are not effective when scanning through a panel cover.

Interestingly different fuses have different temperatures from type to type and Mfg to Mfg. Good reason to not intermix Mfgs and/or types.
 
Correct me if I'm wrong but the marking on equipment means such as 40c on a standard plug in circuit breaker is the max. operating temp above ambient temperature.
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No that is the maximum ambient and the temperature rise is above that.
Temperature Testing The UL 489 Standard allows for two types of
ratings. Standard circuit breakers cannot exceed a maximum of 50?C temperature rise at the wire terminal connection at 100%current in 40?C open air. 100% rated circuit breakers may have a temperature rise of 60?C at the wire terminal connection in the smallest allowable enclosure if
the circuit breakers are connected with wire rated at 90?C wiring insulation sized to the 75?C chart (Table 310-16, National Electric Code?—NEC?).
The ANSI C37 Standard requires a maximum of 55?C temperature rise at 100% in the smallest enclosure and a maximum of 85?C temperature rise on the contacts.
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Don
 
IR Level 1 Certification teaches a technician to make determinations, i.e. A 20 amp breaker with a temperature of ____ in an ambient ____ of carrying 5 amps is acceptable or not.

I am sure this information is available on line, but in lieu of that the best thing is comparative readings (as noted), FOP test (Fall of Potential) and intuitive reasoning that comes with experience.
 
we use the infrared for comparative readings. if there is a potential problem just like the one you described, we verify it by taking current readings
 
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