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A Basic Guide to Circuit Breaker Types

Posted by K.E. Gregoric on Oct 6, 2016 7:45:00 AM

48871.jpg Modern machines of all types are setting aside fuses in favor of circuit breakers. Circuit breakers have quite a few virtues; they're more durable, they're easier to reset and replace, and they can be ordered in types that fit in where most fuses were used on vehicles. Still, it's important to know the different circuit breaker types and their uses.

Circuit Breakers: An Overview

A circuit breaker's function is right there in the name; when it detects high amperage or another electrical problem, usually by a circuit heating up, it flips and cuts off the circuit, protecting sensitive electrical systems from damage. Generally, they come in three broad categories: auto, manual, and push-to-trip, and in three different types: I, II, and III. These can overlap somewhat depending on the design of the breaker.

The broad categories describe how the breakers reset. Auto means the breaker self-resets without help from the user, manual requires the user to reset the circuit themselves, and push-to-trip allows you test the circuit by pressing a button and breaking the circuit. Push-to-trip, also called "switchable," is an especially important breaker type because it allows you to force anybody accessing certain vehicle systems to cut those off from power before opening. Generally, systems wired directly to batteries and other heavy shock risks will have push-to-trip breakers that make it impossible to put current through the system while repairing it.

 

Types Of Circuit Breakers


Mid-Range Circuit BreakerIn automotive, circuit breakers generally fall into three types. Type I breakers are, without exception, automatic. They'll either cycle or keep resetting until the issue is resolved. Generally, you'll use Type I in applications where you have relatively low voltage and reaching the breaker for a manual reset will be difficult, and which will only occasionally deal with overload situations. That includes systems like wiper motors, headlamps, and non-essential systems like device charges. In short, if it doesn't draw much power and needs to be buried deep in the vehicle where it's hard to get to, it's probably a Type I.

Type II is also automatic in a sense. Most Type II breakers will reset when the ignition is turned off, or the overload is removed, making them perfect for systems that only need breakers when the engine is on. That generally includes systems like power windows, and situations where you don't want to deal with replacing fuses that blow on a regular basis.

Type III is where you'll generally find manual and push-to-trip breakers. All Type III breakers will have a visual indication that the breaker is tripped on the body to better diagnose short circuits and other issues. It's also generally where you'll find the highest amps. For safety purposes, Type III are probably the most effective.


When choosing a circuit breaker, it's important to know both your vehicle's needs and what circuit breaker types best fit what you require. By being familiar with types and categories, you'll be able to meet your fleet's needs more effectively. If you're ready to get the right breakers for you, view our circuit protection products.

Here's a few of our newest circuit breakers:

Cooper Bussmann 22105-300

Mechanical Products Series 19 Circuit Breaker - 60A, Type III, Manual Reset See More

Cooper Bussmann Circuit Breaker - 5A, Type 1 See More

Mechanical Products Series 17 Thermal Circuit Breaker - 275A, Auto Reset, Surface Mount, 3/8" See More

 

Topics: Resources & Tools, Circuit Protection


 

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