What is the Difference Between BS EN 60898 and 60947-2?

Electrical safety is vital for designers and installers. But why are there two separate circuit-breaker Standards? Why not just have one? Here’s a brief introduction to both Standards:

• BS EN 60898: Published by the British Standards Institution, this is the primary international Standard for the design and operation of circuit breakers having a rated voltage not exceeding 44o volts (between phases).
• BS EN 60947-2: Also published by the British Standards Institution, this international Standard states the operation and behaviour of a circuit breaker operating up to 1,000 volts (alternating current) during normal service conditions.

This article will compare these Standards, highlighting their differences and the applications of each.

An Overview of BS EN 60898

What does the BS EN 60898 circuit breaker Standard cover? As the rated voltage can’t exceed 440 volts under this Standard, it is primarily used for circuit breakers in residential, retail, office and school applications. Although these systems are considered “low voltage”, they can still encounter fault conditions such as a short circuit or current overload, and these can damage components or cause overheating that can lead to a fire. These circuit breakers, also known as “miniature circuit breakers (MCBs)”, are designed under the 60898 Standard to operate within specific short-circuit capacities.

BS EN 60898 Circuit Breaker: Key Features and Applications

The miniature circuit breaker (MCB) is ideal for domestic and office applications because it can be operated by an ordinary person (with a simple on/off switch) and is designed for a pollution and humidity-free environment. Its primary function is protection against overloads or short circuits.

This circuit breaker has two tripping mechanisms:

• For overload protection, the MCB typically has a thermally-triggered bimetallic strip. The heat from the overload current causes the strip to expand and trigger the tripping mechanism.
• For short-circuit protection, a magnetic element trips the mechanism. During the short circuit, there is a current surge that causes a magnetic field in the element, and this field attracts the trip lever, which opens the contacts and breaks the circuit.

What is BS EN 60947-2?

The BS EN 60947-2 Standard is titled “Low-voltage switchgear and controlgear - Circuit-breakers”. Low voltage is defined as anything up to 1,000 volts. Switchgear consists of switches, circuit breakers, isolators, relays and fuses used to control, protect and isolate electrical systems. Because this Standard covers higher voltages than homes and offices, its intended use is for industrial applications.

BS EN 60947-2 helps designers and manufacturers create circuit breakers that are compliant with global Standards and provides Standard methods to test the behaviour of circuit breakers under various conditions.

BS EN 60947-2 Standard: Key Features and Requirements

BS EN 60947-2 has the protection of electrical circuits in industrial environments as its focus. While the overall Standard of BS EN 60947 embraces circuit breakers, isolators and disconnectors, BS EN 60947-2 specifically covers the more robust circuit breakers for industrial use.

Included in its scope:

• Specifications for circuit breakers that are meant to provide earth leakage protection.
• There are additional requirements for integrally-fused circuit breakers.
• Methods of designing and testing the electromagnetic compatibility of circuit breakers.

There are two main types of circuit breakers used in industrial applications:

• Moulded Case Circuit Breakers (MCCBs): These use a combination of thermal and magnetic elements to protect the system against short circuits and overloads.
• Air Circuit Breakers (ACBs): Used for more heavy-duty industrial applications, these operate with either pressurised air or insulated gas to break the circuit.

Key Differences Between BS EN 60898 and BS EN 60947-2

While both Standards deal with circuit breakers, they approach them from different “angles”. BS EN 60898 is titled “Electrical accessories. Circuit-breakers for overcurrent protection for household and similar installations”. It treats the circuit breaker as an “accessory” for the less demanding requirements of a home. On the other hand, BS EN 60947-2 covers circuit breakers from an industrial standpoint, hence its title “Low-voltage switchgear and controlgear - Circuit-breakers”, dealing with “low voltages” up to 1,000 volts.

Other differences are:

• BS EN 60898 operates to a maximum of 44o volts (between phases), while BS EN 60947-2 deals with voltages up to 1,000 volts (alternating current).
• BS EN 60947-2 allows for operation under harsher environments than the domestic/office use of BS EN 60898 Standards.
• BS EN 60898 circuit breakers require very little knowledge to operate, while BS EN 60947-2 circuit breakers are only meant to be utilised by skilled personnel.

BS EN 60898 Advantages Over BS EN 60947-2

The BS EN 60898 advantages are mostly found in smaller-scale residential and commercial environments. When dealing with an office, retail store or home, for example, it is much simpler to use the more common and reliable electrical setups found in BS EN 60898 than an expensive tailor-made system for an industrial setup as required with BS EN 60947-2.

The Role of BS EN 60947-3 Isolators in Electrical Protection

The BS EN 60947-3 Standard is titled “Low-voltage switchgear and controlgear - Switches, disconnectors, switch-disconnectors and fuse combination units”. An isolator is a type of switch that disconnects a circuit from its power supply. While the purpose of a circuit breaker is to protect the circuit from current overload or short circuits during load conditions, the BS EN 60947-3 isolator is typically used to open or disconnect a circuit during a no-load condition. This makes it safe to repair and maintain any part of a circuit used in industrial and high-voltage environments.

BS EN 60947-3 Isolator: Applications and Compliance

A BS EN 60947-3 isolator (switch disconnector) is designed and installed into circuits used in industrial environments with loads up to 1,000 volts. Safety regulations require that the power supply be completely disconnected from the circuit to allow personnel to perform repairs or routine maintenance. The BS EN 60947-3 Standard outlines the best practices for manufacturers to design and manufacture isolators in compliance with those regulations.

Choosing Between BS EN 60898 and BS EN 60947-2 for Your Electrical System

In most cases, the decision should be clear-cut. Are your circuit breakers going to be used in a residential/office installation or an industrial one? If you’re still not sure about the scale of the electrical system needed, you could look at other factors, such as cost and your protection needs. If your system has a rated voltage not exceeding 440 V (between phases), BS EN 60898 will likely be most applicable.

Conclusion: Why Understanding BS EN 60898 and BS EN 60947-2 Matters

It’s vital to understand the difference between BS EN 60898 (domestic) and BS EN 60947-2 (industrial) when designing, constructing and installing circuit breakers. The correct choice of Standard can impact electrical safety, system reliability and compliance. You can consult with our experts when selecting the right protection Standards or solutions for your needs.