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Non-Contact Thermometer readings - Breaker box and elsewhere

Non-Contact Thermometer readings - Breaker box and elsewhere

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  #1  
Old 11-11-13, 05:26 AM
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Non-Contact Thermometer readings - Breaker box and elsewhere

I picked up a cheap infared noncontact thermometer. I was putting it thru the paces. On my circuit breaker panel I noticed the breakers were reading about 65 degrees. Including the main breaker.

However, my dryer was running for about an hour that day and that breaker was measuring about 70 degrees.

Im just curious what type of temerature swing would be normal with breakers?

Any other information about heat and devices would be interesting too.

Thanks
 
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Old 11-11-13, 05:28 AM
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Fahrenheit, Centigrade, or Kelvin?
 
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Old 11-11-13, 08:56 AM
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65'-70' c. Not sure if I can toggle between on my thermometer.
 
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Old 11-11-13, 06:42 PM
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I picked up a cheap infrared non-contact thermometer. I was putting it thru the paces. On my circuit breaker panel I noticed the breakers were reading about 65 degrees [C]. Including the main breaker. [...] I'm just curious what type of temperature swing would be normal with breakers?
IDK. For one thing, it sounds like you just opened the door and scanned the faces of your breakers. For another, "temperature swing" is not a measurement I'm familiar with with breakers.

Infrared scanning is done every day on distribution panels as part of regular maintenance. The way it is done is by removing the deadfront and scanning the interior. Most often, this is done by taking an infrared image of the wiring. What we're looking for when we do that is "hot spots." Those are typically found at terminations and at wire bends. A hot spot at a termination usually indicates a loose connection. A hot spot at a wire bend almost always indicates that that wire was bent sharply enough to damage the conductor by thinning it enough to increase its resistance (decrease its ampacity).

With the advent of hand-held non-contact temperature sensors like the one you bought, some contractors have started using those to do a scan to determine whether a particular panel shows might have any hot spots, and therefore warrant imaging.

The last I heard, the jury was still out on whether basing a decision on imaging the panel on the basis of a scan with a non-contact thermometer - adopted to increase "efficiency," of course - decreased effectiveness enough to warrant its being banned, or had so little effect on that that it was deemed acceptable.

A well-made and properly installed breaker won't be adversely affected by the temperature generated by its use. Its designed function is to protect the conductor it's supplying against thermal overload. In order to do that, it must be able to function at temperatures well above those which would damage the conductor it's protecting. As a reference point, consider that the conductors being installed today are made to withstand up to 90[SUP]o[/SUP] C., or 194[SUP]o[/SUP] F., because their insulation is better than that on older conductors. Those are typically rared at 60[SUP]o[/SUP] C., or 140[SUP]o[/SUP] C.
 

Last edited by Nashkat1; 11-12-13 at 09:44 AM.
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