Improving Arc Flash Prevention and Safety

November 14, 2016

By Steve Sullivan

Working among the electrical components in an enclosure comes with inherent risks. The power in any one enclosure can range from 2kw up to 200kw depending on the power density. One of the most common and dangerous risks is an arc flash (or flashover).

When an explosive release of energy erupts from a phase-to-phase or phase-to-ground arc fault, the results range from devastating to deadly. This air to ground electrical explosion is a critical concern.

The destructive force of an arc flash

The dangers from an arc flash are all too well known. When metal expands and vaporizes at the fault, it causes extreme heating of the air, upwards of 10,000°C/18,032°F. The concussive pressure wave can knock personnel off their feet; the ultraviolet light flash can cause blindness; the sound blast, deafness; and the molten metal and heat can cause second and third degree burns. The specific death toll has been estimated to be up to 1-2 people every day worldwide.

An arc flash can result from unsafe work procedures, accidental contact, or more systemic problems such as corrosion of components and connections or insulation failure. Arc flash prevention should be incorporated into any application from the beginning of the design process.

Minimizing arc flash exposure

Design and retrofit approaches can limit exposure by using components installed outside the enclosure to permit qualified personnel in personal protective equipment (PPE) to service equipment inside without opening the enclosure door. Interface flaps and window kits permit data retrieval, equipment monitoring or routine maintenance to be performed from outside. Collapsible fold down shelves be raised for use with laptops and monitoring equipment. External data pockets can hold wiring diagrams, operation manuals and other documents.

Arc flash protection

Sometimes components must be accessed from inside the enclosure. For example, Rittal’s arc flash solution keeps high and low voltage equipment within the confines of their own respective enclosures. Low voltage enclosures house equipment that is used for programming, data acquisition and system adjustment.

High voltage components are isolated within their own disconnect enclosure, while line side power is segregated within the power isolation enclosure. A partition wall acts as a barrier to high voltage line side power. An interlocking door system ensures that the high voltage enclosure cannot be opened while the disconnect switch is in “ON” position.

For additional safety, all interlocked doors and master door must be closed in order to re-energize the enclosure. This removes potential for accidental contact with the inline power when the disconnect enclosure is put in a safe power-off position, and locked and tagged out.

Minimizing exposure to line side power can help protect personnel from accidents. A qualified person wearing PPE and following appropriate safe work practices can perform visual inspections and tasks, such as diagnosis, testing, troubleshooting and voltage measurement with the door open even when the main enclosure is energized.

Safety is always your priority, so download Rittal’s Arc Flash and How to Prevent it free whitepaper for the first step towards arc flash prevention: http://info.rittalenclosures.com/arch-flash-lp-0.

Steve Sullivan is a training manager with Rittal. This article was first published online as a blog: http://blog.rittalenclosures.com/blog/author/steve-sullivan-training-manager.

 

Related Articles


Latest Articles


Changing Scene

  • Thermon Expands Electric Heater Offering Through Aquisition of F.A.T.I.

    Thermon Expands Electric Heater Offering Through Aquisition of F.A.T.I.

    October 25, 2024 Thermon has announced the acquisition of Fabbrica Apparecchiature Termoelettriche Industriali S.r.L. (F.A.T.I.), a manufacturer of electric heaters for industrial applications, based in Milan, Italy. F.A.T.I. is a leading designer and manufacturer of electrical heaters and heating systems for a broad range of industrial end markets, including oil & gas, pharmaceutical, renewables, nuclear… Read More…

  • CDM2 Partners with ELEC-TECH Sales to Expand Emergency Lighting Solutions Across BC

    CDM2 Partners with ELEC-TECH Sales to Expand Emergency Lighting Solutions Across BC

    October 25, 2024 CDm2 LIGHTWORKS is pleased to announce a strategic partnership with Elec-Tech Sales to bring ABB LUMACELL emergency lighting products and systems into their diverse application-driven solutions. “This partnership with Elec-Tech Sales strengthens our ability to deliver a robust portfolio of integrated lighting, controls, and electrical solutions,” noted Darren Luce, President + Principal of CDm2 LIGHTWORKS. “Together,… Read More…

  • Manitoba Government Introduces Legislation to Help Build New Housing Faster

    Manitoba Government Introduces Legislation to Help Build New Housing Faster

    October 25, 2024 The Manitoba government has introduced amendments to the Planning Act and the City of Winnipeg Charter Act that would change the appeals process for zoning changes by removing a requirement that made it difficult for municipalities to change local zoning bylaws and allowing faster new housing construction, Municipal and Northern Relations Minister… Read More…

  • Piloting New Ways to Make Homes More Energy-Efficient and Affordable

    Piloting New Ways to Make Homes More Energy-Efficient and Affordable

    October 22, 2024  Canada’s buildings sector is the third-largest contributor to greenhouse gas emissions across the country.  We must increase the scale and pace of retrofitting buildings across the country to make them more energy-efficient, increasing savings and reducing emissions. A federal investment totalling $4.3 million has been announced for five projects funded under the Greener Neighbourhoods Pilot Program (GNPP)… Read More…