Author: Josie

Safety is important and the main line circuit breaker (MLCB) plays a key role in protecting people and equipment. This main breaker is placed between the generator end and the load. All of the electrical current goes through this breaker. If there is too much load it will trip and interrupt the current to help and prevent damage or overload.

Many of our products have multiple receptacles. The MLCB serves as the main safety gate and feeds additional circuit breakers that protect the individual receptacles. The picture below shows a WL18000VE and how the smaller circuit breakers (CB) and receptacles all wire through the MLCB. The MLCB is normally rated at 100-125% of the generator output.

In some applications it makes sense to have dual breaker systems. For example, the WL22000VE panel below has two breakers that provide the main line protection for half of the receptacle panel. The ratings of both breakers are specified to be equal to 100-125% of the total generator output.

Circuit breakers are designed to interrupt current when there is too much load on a circuit. They are designed to stop the flow of electricity to prevent injury or the failure of other electrical components like the wiring, generator end or receptacles. Winco uses multiple types of over-current protection technologies based upon the application.

Thermal

A thermal breaker, as it sounds, works with heat. Current (amps) creates heat as it passes through the breaker, if the breaker gets too warm, it opens a switch that is normally spring loaded to open the circuit and stop the electrical current.

• Advantages: Less expensive and has a time delay as the breaker heats up.
• Disadvantage: Slower reaction and is affected by ambient temperature.

Magnetic

A magnetic breaker has a coil. When excess current passes through, it becomes a electromagnet which opens the breaker.

• Advantages: Very fast to high current like dead shorts.
• Disadvantages: Can’t handle the slow overload trip with time delay.

Electronic

With an electric breaker, a computer chip controls the trip point and delay precisely. We use electronic breakers on our generators above 100kw so you can set the trip point and switch between voltages using the same breaker.

• Advantages: Quick, precise trip
• Disadvantages: More expensive

Hydraulic

A hydraulic breaker is similar to a thermal breaker, but instead of using heat, a viscous liquid control the trip point.

• Advantages: Not affected by ambient temperature and a delayed trip is possible
• Disadvantages: Not available in all sizes

In order to get the best combination of trip characteristics many circuit breakers combine technology. For example, a thermal/magnetic breaker has a slow reacting thermal trip mechanism and a fast reacting electromagnetic mechanism. Winco indicates which safety technology the main line circuit breaker is using on our spec sheets.

That is a great question. Simply put it is a safety device that can stop the flow of electricity in a circuit. It is important to understand the limitations of a circuit breaker in your application to make sure you are protected. It is easy to get into trouble when we misunderstand what the CB actually protects against.

A circuit breaker interrupts power in two main configurations switching and interrupting.

It is important to remember that circuit breakers focus on controlling the amount of current in the circuit and don’t monitor voltage or power quality. You can also compare a CB to a fuse. The main difference is, when a fuse has too much current, it breaks itself to stop. Where as, a CB is re-settable while normally not getting ruined once it has tripped.

Click to view our spec sheet on circuit breakers.