More Technical Stuff About Circuit BreakersInside most circuit breakers there are two types of protection: One is thermal. The other is magnetic. The thermal strip measures heat build-up caused by overloading. When it reaches a certain temperature, it will shut off the breaker. The magnetic coil measures sudden increases in current (such as a short). At a predetermined limit it will shut the breaker off. Older breakers sometimes have only one of these features. For maximum protection, a breaker with both types of protection is recommended. There are usually three spots on the outside of a breaker that show wear. If the “ON/OFF” switch (located at the top) has broken off or is loose, we recommend the breaker be replaced. Next is the load lug. If it is burnt or abnormally loose, we recommend the breaker be replaced. Last, and most common, is the stab. The breaker stab is what makes contact with the bussing in the panel (the bussing carries the power throughout the panel). The stab connects to the bussing through friction and spring tension. The spring tension, over time, may break down. If so, arcing or burning may result. If the stab has become burnt, discolored, or is abnormally loose, we recommend that the breaker be replaced and that the bussing in the panel be checked. NOTE: It is possible for a breaker to appear OK in regard to it’s outward appearance and its capacity to carry continuity, but still be questionable, bad, or intermittent. The opposite may be true as well. A breaker with a poor outward appearance may be perfectly safe and structurally sound. Therefore a decision to replace a breaker should not be based solely on appearance, continuity, age, etc. A good electrician can recommend the proper course of action based on taking into account all the relevant factors.
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