The National Fire Protection Association standard for "Electrical Safety in the Workplace" (NFPA 70E) calls for an arc-flash hazard analysis. To comply you must determine both a "flash protection boundary" and the personal protective equipment (PPE) requirements for people working within that boundary. In Part 1 of this series, we'll explain what a boundary is and why it's necessary. Next week, in Part 2, we'll discuss how to calculate a flash protection boundary. In the last installment, we'll explain what you should do regarding PPE once you've determined an appropriate boundary.

Why a Boundary Is Necessary

An arc-flash that causes an incident energy of 1.2 calories/centimeter 2 (cal/cm 2 ) or greater at the skin's surface may lead to a permanent injury (second degree burn or worse). The arc-flash boundary determines at what point PPE is required to protect an individual from permanent injury.

When a Boundary Is Necessary

Arc-flash boundaries are required when someone works on or in the proximity of "exposed energized" components - components that are energized and not enclosed, shielded, covered or otherwise protected from contact. This includes:

• Switchboards
• Panelboards
• Industrial control panels
• Motor control centers
• Other similar equipment

Work activities include:

• Examinations
• Adjustments
• Servicing
• Maintenance
• Troubleshooting

Note: Equipment energized below 240V is of no concern unless it's fed by a transformer of 112.5KVA or larger.

Next week, in Part 2, I'll show you how to calculate the arc-flash boundary.

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Odd job

ODD JOB

SULKY DRIVER

No, it's not a cabbie with an attitude. "Sulky driver" is another name for a person who drives a sulky, that is, a horse-drawn, two-wheel cart in a harness race.

Sulky drivers need to be observant and safety-conscious. They must love horses, be physically fit and have good upper body strength. They also need to be small and light. Tasks include grooming and caring for the horse and planning race strategies.

A sulky driver and his one-horse power engine

Sulky drivers put in long hours, caring for their horses seven days a week, and often racing in the evening. The pay is low - anywhere from $14,000 to $21,000 per year; however, sulky drivers also get a percentage of what they win.

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