Whats the normal temperature for breakers

I would like to know if any of you use infared to read the temperature of breakers?

What is temperature I should begin to question the condition of the breaker, or wiring attached to that breaker?

Hi …I had a simular question regarding AFCI breakers the other day .
If that is what you are concerned about I found out they can run around 15 0r 20 degrees hotter.

Thats good information to have. Thanks.

I have never taken the temperature of a breaker. What should I expect to read from a typical breakers?

To be honest I will not get heavy into the temp thing, as it may be going overboard .I used my gun because I thought the AFCI’s were overly hot.
We got enough to look at.
The Flir guys are more into that stuff as part of their routine.
Put it this way.
Say you run the gun and find a two degree variation.
OK now what?
If the dishwasher was just run before you got there will it affect your readings? You get my point.

I agree with not wanting to make more work for myself.


and possible liability

Breaker temperatures can vary from low to relatively hot. There really is no “normal” temperature. There are too many variables that would come into play.

I will agree with Jpope on this one.

I do take the temperature of the breakers too., but there are too many way to tell if this is normal or not.

kinda like a judgment call on breakers just like the example one breaker will be pretty close to 80 % full load it will show up very warm while other breakers is very low loaded so it will show cooler than others so there is not a really a excat guideline to determed if that is the breaker or connections is overheating you may have to check each one indually to determed if it is normal or not.

I am not sure which electrician in this fourm here do have specal camera to tell you the details not all of us have it ] so just want to be fair with you.

Merci, Marc

Exactly what I was saying.
Dead subject .

Hi. Bob;

You guys with your fancy toys, ha. ha.

I can’t afford that luxury, so I still take my electrical panels temperature the old fashion way.

Check temperature top and bottom of panels.

Temperature recorded at top= 72 degrees
Temperature recorded at bottom= 68 degrees.

I guess I am alright.


Marcel :slight_smile: :smiley: :wink: :wink:

I do it the real old fashioned way, with the back of my fingers. If I can keep my fingers there comfortably, its not too hot.

:wink: Get your hands out of that live panel you goof.

All right, you guys win, I promise that innovations and technology will inherit the earth, so I will try to follow you guys in this new tool technology.



**On average, approximately one third of all property losses are electrically related. Fully one fourth of those losses are caused by faulty electrical connections. In such cases, loose, dirty, damaged, corroded or oxidized connections and contacts inevitably lead to increased electrical resistance - generating heat and infrared energy as a result. Such problems, given sufficient time, inevitably result in fire or explosion. **

Identifying electrical threats before they reach combustion or component failure temperatures is becoming increasingly more difficult due to the complexity of today’s building operation systems and control equipment. In addition, the sheer number of contactors, breakers, fuses, and other electrical service hardware make it virtually impossible to physically inspect, shut down, and tighten every electrical connection on any regular basis.

With occupant safety, energy conservation, minimal downtime and the protection of capitol equipment all being synonymous with proper maintenance, more and more building operators are turning away from occasional physical electrical checks in favor of the latest preventative maintenance technologies.


**Infrared Thermography (IR) operates by measuring the infrared energy of any object’s surface and producing a detailed visual image showing its temperature profile. Since IR operates without physical contact, it offers building operators a safe, on-line, and cost-effective means to evaluate the electrical operation of any property. While many borderline problem areas typically remain undetected during an off-line physical inspection, they can be easily pinpointed using IR. **

Infrared Thermography is ideally suited for detecting faults in electrical panels, breakers, switchgear, splices, insulators, starters, contactors, wiring, distribution systems, disconnects, and transformers, etc. With a lesser degree of reliability, IR can locate water leakage in roofs, steam trap malfunctions, ineffective HVAC air distribution patterns, motor and bearing defects, building energy loss, pipe blockages and underground pipe leakage - providing a visual representation of the heat generated or lost in almost any physical application.


**The below series of photographs help show the potential of infrared technology, and why it is considered one of the most valuable nondestructive tools available. The control or standard photograph on the left helps to identify the source of the problem; the infrared image the problem. **

In many cases, the highest temperature value and most defined point within an infrared photograph will identify the actual source of the problem - such as a single bolt, electrical component, or contact surface.




Knife Switch - Knife switch contacts present a constant maintenance problem to most older properties. Annual IR inspections of such properties typically find multiple contact problems which can only be repaired by shutting down the equipment, disassembly and cleaning of the contacts, reassembly, and re-tensioning. Upgrading with new disconnect equipment is recommended as the obvious long term solution.




**Transmission Lines - This 460 volt tower between buildings showed a problem at an old splice. Temperatures were measured at near 300 degrees F., and had charred the nearby wire to bare metal. A combination of weathering, old age, and a less than acceptable wire splice ultimately produced this electrical problem. **




**Knife Switch - Knife switches and most types of sliding electrical contact always present the potential for hot spot problems. Add to them the moisture present in an outdoor environment and serious faults can result. In this example, the A phase of this disconnect switch was found exceeding 350 degrees F. **


For most infrared inspections, a client’s primary interest is to identify the hot spot locations presenting the most serious and immediate threat. However, other electrical and mechanical problems may exist which may also present a potential threat to reliable building and plant operations.

**A typical IR inspection may identify panel doors damaged, mismatched or over rated fuses in place, indicator lights out, inoperative safety mechanisms, as well as various other forms of potential electrical or mechanical threats and liabilities. Unlabeled panels, while not in themselves an operating problem, would likely slow an emergency response to one. **

Emergency automatic transfer switch (ATS) equipment, tested only in normal mode, would not guarantee proper operation during emergency power. Similarly, testing switchgear and starter panels under little or no load, such as often exists for momentary or standby equipment, would not likely show a problem. Identifying such equipment for special attention during future inspections, therefore, will greatly benefit any building or plant operation.

**Marcel:) :slight_smile: **

Exactly done it that way for almost 50 years and To test motors If you can keep your hand on it and count to ten its OK .
Some times you learn to count real fast then blow air on your hand.
… Cookie

To all of you that do not take some form of temp reading…
I have always taken the temps of electrical panels. Never had a substaintial temp difference until two weeks ago. The main breaker and SE (only one side) was 410f. :shock: Sure am glad that I checked.:wink:

The acceptable operating temperature of a circuit breaker is defined by UL in the UL489 standard (June 2011), which is listed below.

Terminations for standard rated breakers: Paragraph says the temperature rise on a wiring terminal at a point to which the insulation of a wire is brought up as in actual service shall not exceed 50°C (90°F).

Terminations for 100% rated breakers: Paragraph says the temperature rise on the termination shall not exceed 60 deg. C (108 deg. F).

Handles, knobs and other user surfaces: Paragraph says the maximum temperature on handles, knobs, and other surfaces subject to user contact during normal operation shall not exceed 60°C (140°F) on metallic and 85°C (185°F) on nonmetallic surfaces.