Short #79 - Circuit Breaker Facts
HVAC School - For Techs, By Techs
Bryan Orr
4.9 • 1K Ratings
🗓️ 12 November 2019
⏱️ 16 minutes
🧾️ Download transcript
Summary
In this short podcast episode, Bryan talks about circuit breaker facts. He also explains why they trip, what they do, and some different types and considerations.
Circuit breakers break the circuit during an overcurrent situation. These do NOT handle all overloads, such as locked rotor amps (LRA); these handle significant overloads, such as shorts (when current takes undesigned paths). In air conditioning, we can size our fuses and circuit breakers a bit larger than usual, which prevents tripping from small spikes instead of truly dangerous or prolonged overload conditions.
There are thermal and inductive circuit breakers. A thermal circuit breaker uses heat to determine when to trip; these are common breakers but are prone to nuisance trips from poor connections or on days with high ambient temperature. Inductive trip breakers are magnetic and trip at a certain point of inductance; these are not easily affected by ambient temperature but can be expensive.
A breaker's temperature can tell you a bit about its condition. Hotter breakers may be closer to tripping. However, arc fault breakers, a type of thermal breaker, can also run hot but work fine, which may confuse technicians. You can use thermal imaging cameras or infrared thermometers to compare breaker temperature.
Dielectric grease is a good tool but requires plenty of attention. You need to have the right connectors before you even reach for the grease. The dielectric grease protects the connectors from corrosion (from the outside), and it should NOT go directly on the connectors. Some people also use anti-seize grease; no matter which grease you use, you must be careful and avoid adding resistance.
Bryan also discusses:
- Proper torque settings
- Measuring voltage drop across the device
- Using breakers as switches
- Double-lugging
- Arc fault vs. GFCI
Learn more about Refrigeration Technologies HERE.
Transcript
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| 0:00.0 | This is the HVAC school podcast and my name is Brian. Thank you for taking these |
| 0:08.2 | couple minutes short minutes and listening to this quick episode and today we're going to be talking about |
| 0:13.7 | circuit breakers. Everything you wanted to know and maybe some things you didn't |
| 0:16.9 | want to know about circuit breakers. Actually, this isn't an engineering level |
| 0:20.6 | thing. That's not something I do at HVAC school. |
| 0:24.0 | I do try to stay away from really deep math |
| 0:26.5 | just because the bulk of the people who listen |
| 0:28.3 | are in the trade on the repair and installation side, |
| 0:31.8 | not so much on the engineering and design side. |
| 0:34.0 | So even though that stuff does interest me, |
| 0:37.0 | it's not really what we talk about here, mostly application. |
| 0:40.0 | Anyway, I digress. |
| 0:41.0 | Our sponsors for the podcast are a few of them, and they're all great. |
| 0:45.2 | The first one I want to mention is Fieldpiece.com. Fieldpiece makes amazing |
| 0:49.7 | test instrumentation. They're coming out with some new multimeters if they're not out yet |
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| 0:58.0 | like is the SM 380-V manifold. It's what I have on my truck now and it just has all the bells and |
| 1:04.5 | whistles and it works great and it also works with Measure Quick and it also works |
| 1:09.0 | with their Jobling Probes. So they just took everything and put it into one device and it's got great water |
| 1:15.5 | resistance very ruggedly built the hook on it is super beefy a lot to like about it so |
| 1:20.1 | take a look at that you can go to truetech tools. Come and find that. |
| 1:23.2 | And then also Navac's coming out with all kinds of great stuff. |
... |
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