Reducing Arc Flash Risk and Increasing Safety in LV Switchboards

Reducing Arc Flash Risk and Increasing Safety in LV Switchboards

Posted by E-I Engineering on Jun 13, 2018, 5:37:24 PM

What is an arc flash?

An arc flash is defined by NFPA 70E-2012 as ‘a dangerous condition associated with the possible release of energy caused by an electric arc’.
Put simply, an arc flash is a type of electrical explosion that occurs when current that flows through the air flashes from one live conductor to another conductor or to the ground. The light and heat produced from an arc flash consists of ionized air at very high temperatures – three times hotter than the surface of the sun. An arc flash can vaporize copper, cause pressure build up and an explosion in enclosed equipment.
Arc flash incidents are extremely dangerous, killing workers every year and permanently burning and injuring many more.

What causes an arc flash?

An arc flash occurs when electrical clearance are compromised by deteriorating equipment or human error. Hazardous arc flashes can take place in electrical switchboards due to a number of factors including:

  • Poorly maintained equipment
  • Poor operating environments
  • Accidentally dropping conductive equipment into equipment e.g. metal tools
  • Incorrect alignment of contacts in withdrawable breakers
  • Loose connections overheating
  • Rodents/Vermin in switchboard
  • Defective busbar insulation

 

Mitigating the risk of arc flash incidents with arc resistant switchboards

In the past 10 years, awareness of arc flash hazards has increased greatly among electrical workers, engineers and safety personnel. NFPA 70E-2012 contains extensive information on safe work practices, documentation, labelling, correct PPE etc. but there has been relatively little attention paid to designing arc resistant solutions that reduce the chances of an arc flash event and reduce the impact of these events if they do occur.

The most effective arc flash reduction measures are those that do not rely on worker training, warning signs etc. E+I Engineering’s approach of ‘safety by design’ has been proven to be a much more effective mitigation technique.

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5 ways E+I Engineering’s equipment can reduce the risk of arc flash

  1. REMOTE RACKING

Maintaining a safe distance between personnel and equipment during critical operations provides the most effective means of avoiding injury by keeping people out of harm’s way. Remote racking in particular provides a safer operating environment for personnel through the proven method of adding distance between the operator and arc flash incident. E+I Engineering utilize vacuum circuit breakers with a fully integrated motor operated racking system that facilitate remote racking to protect users.

2. COMPARTMENTALISATION OF COMPONENTS

E+I Engineering’s Powerboard SB891 range and IEC approved switchgear range is available in all Forms of Separation up to Form 4 Type 7. This compartmentalization of components and busbar utilizes sealed modules protects the operator and the equipment while in use.

3. FULLY TESTED ARC-RESISTANT SWITCHGEAR

All E+I Engineering switchgear has been tested to the most rigorous levels – including initiating arcs in all components (breaker, busway and cable) for a full 0.5 seconds to guarantee the safest arch resistant switchgear in the industry. Some manufacturers do not publish details arcing duration or arc initiation information on their products, despite claiming them to be arc resistant.

4. APPROPRIATE TRAINING FOR PERSONNEL

All workers who will work on or near exposed energized parts must be ‘qualified workers’ and those individuals need specialised training to help prevent electric shock. Other workers are considered ‘unqualified workers’. They primarily need to be trained to recognise hazardous situations and keep away from them. Qualified workers must be trained to deal with those situations safely as part of their duties. The distinction between qualified and unqualified workers is difficult to make and therefore E+I Engineering advocate that even non-electrical workers should receive electrical safety training if they are exposed to an electrical hazard. E+I Engineering offer full system training on our full range of equipment.

5. PREVENTATIVE MAINTENANCE PLAN

One of the most effective ways to prevent arc flashes is to anticipate and eliminate the conditions that cause them; this can be achieved through a preventative maintenance plan. Preventative maintenance systems provide early warning of failures in switchgear. Deteriorating switchgear and poorly maintained equipment is the leading cause of arc-producing electrical failures. Identifying and repairing compromised component before they fail can help avert arc flash explosions. E+I Engineering offer a comprehensive preventative maintenance plan to ensure the reliability of electrical installations in the long term and to help to mitigate the risks associated with the continued operation of electrical distribution systems.

Electrical hazards are a significant safety and financial risk for electrical workers and their employers. Given the dangers that they pose, arc-flash incidents merit serious attention from engineers. Although the risk can never be fully eliminated, utilising the solutions provided by E+I Engineering can help to ensure that arc flash incidents are less likely to happen and less harmful when they do.


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