Why remote racking of LV/MV circuit breakers is a smart investment but so rare to see?

Circuit breaker racking

Circuit breaker racking is one of the most prominent exercises in the power system that exposes an operator to risk. A sudden malfunction during the racking process can induce catastrophic consequences to the operator and entire premises. Older breakers with more complex and relatively vulnerable mechanical orientation are more prone to safety problems encountered during racking.

One of the most talked-about risks during circuit breaker racking is the arc flash phenomena. Arc flashes result from imperfection in the mechanical operation of a circuit breaker while engaging or disengaging. Arc flashes are potentially fatal and disastrous, depending upon the magnitude of current and energy involved.

While there are many maintenance checklist and precautions to minimize the risk of arc flashes, they leave no time to react once they occur. Thus, it is essential to implement an appropriate protective technique to safeguard the operators from potential fatality.

Though this method is way more effective than using Personal Protective Equipment (PPE) or other prevalent preventive techniques, it is not yet widely used. In this article, we will contemplate the use of remote racking of circuit breakers and possible reasons for their limited practice.

Table of Contents:

1. Arc flash and its causes
2. Various methods for reducing and dealing with arc flash
3. Implementation of remote racking of circuit breaker and its working mechanism
   1. Advantages of remote racking over other preventive methods
4. What keeps the remote racking system from being extensively used?
   1. Confusion regarding a retrofit solution
   2. Lack of proper safety training and awareness
   3. Cost factor
5. Why it’s wise to invest in circuit breaker remote racking?
   1. For a simple yet uncompromised safety measure
   2. To make sure human fatalities and related consequences are minimized
   3. Remote racking is the future of switchgear safety

1. Arc flash and its causes

Arc flash is an unwanted occurrence in an electrical system that is associated with an explosion caused due to a rapid rise in temperature and pressure in the air between electrical conductors that is caused by unwanted electric discharge through the air via non-intentional low impedance path.

Arc flashes usually lead to fires and heat that may result in fatalities. The temperature of an arc flash can reach extremely high value and ignite clothing, burn the skin, cause lung or eyesight damage, or even death based on the distance of impact.

Low voltage breakers are more prone to arc flashes due to high fault current associated. Most incidents occur due to human errors and negligence of technicians while working on low voltage switchgear.

The nature of error varies over a wide range- slipping some tools while working on particular electrical equipment, accidentally touching the wrong surface with a test probe, improper installation, etc.

Periodic and preventive maintenance issues like insulation damage, wear and tear, corrosion dust in electrical conductors, exposed parts and loose connections make the condition even worse. Another major cause of arc flash is voltage transients resulting from switching reactive loads or lightning strikes.

Electrical Safety Practice – Lockout Before Work, Test Before Touch!

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2. Various methods for reducing and dealing arc flashes

Because of extremely dangerous and fatal consequences of arc flashes, IEEE, NFPA (National Fire Protection Association), and OSHA (Occupational Safety and Health Administration) has laid out various standards to deal with the heat, toxic gases, radiation, and flying debris generated from the arc flashes.

NFPA 70E and IEEE 1584 are standards that define or set the measures for mitigating the excessive heat released during arc flashes. OSHA enforces these safety standards for employees and helps to determine the appropriate Personal Protective Equipment (PPE) to reduce injuries and burns from arc flash, based on the arc flash hazard assessment.