Arrangement of one and half breaker system

A one-and-a-half breaker system, also known as a "one-and-a-half" or "1.5" breaker system, is a type of electrical circuit breaker arrangement used in some electrical distribution systems. Here's a breakdown of how it works:

What is a one-and-a-half breaker system?

In a one-and-a-half breaker system, there are two main circuit breakers:

  1. Main Breaker (1): This breaker is responsible for feeding the entire electrical system. It's usually a larger, more robust breaker that can handle the total load of the system.
  2. Feeder Breaker (0.5): This breaker is responsible for feeding a specific section or "feeder" of the electrical system. It's usually a smaller breaker that can handle a portion of the total load.

How does it work?

Here's a step-by-step explanation:

  1. The main breaker (1) is responsible for feeding the entire electrical system. It's usually connected to the electrical panel or main distribution board.
  2. The feeder breaker (0.5) is connected to the main breaker (1) and is responsible for feeding a specific section of the electrical system.
  3. When the feeder breaker (0.5) trips, it interrupts the power supply to the specific section of the electrical system it's feeding.
  4. The main breaker (1) remains intact and continues to supply power to the rest of the electrical system.
  5. If the main breaker (1) trips, it interrupts the power supply to the entire electrical system.

Advantages of a one-and-a-half breaker system:

  1. Improved fault isolation: The feeder breaker (0.5) helps to isolate the fault to a specific section of the electrical system, reducing the impact on the rest of the system.
  2. Reduced downtime: If a feeder breaker (0.5) trips, only the affected section of the electrical system is affected, reducing downtime and minimizing the impact on the overall system.
  3. Increased reliability: The one-and-a-half breaker system provides an additional layer of protection and redundancy, making the electrical system more reliable and less prone to failures.

Common applications of a one-and-a-half breaker system:

  1. Commercial buildings: One-and-a-half breaker systems are commonly used in commercial buildings, such as offices, shopping centers, and hospitals.
  2. Industrial facilities: They're also used in industrial facilities, such as factories, warehouses, and manufacturing plants.
  3. Large residential complexes: In some cases, one-and-a-half breaker systems are used in large residential complexes, such as apartment buildings or condominiums.