Deadly Monster Not Tamed by Engineering Alone.

NFPA 70E and Real Safety in the Workplace

By Jeff Beukema, Electrical Services Consultant

Transworld Inc. Electrical Contractors

Charleston, SC

This is a non-technical monolog about safety in the workplace, specifically about electrical safety in the workplace, and even more specifically, about NFPA 70E arc flash safety.

Most commercial, industrial, and institutional owners and managers are acquainted with, or becoming acquainted with, the NFPA 70E Standard as to how to best comply with OSHA’s General Duty Clause calling for creating and maintaining a safe work environment. Because protecting human health and welfare is always a top priority, and electrical hazards are one of OSHA’s “Fatal Four” violations, and due to OSHA’s mandate of adding insult (high dollar fines) to injury (frequently severe when electricity is involved), owners and upper management are listening and acting.

The 2015 edition of NFPA 70E is similar to previous editions in that it contains equations that only a professional engineer can appreciate. Naturally, the inclination is to retain such an engineer to wade through all of those calculations, place appropriate hazard labels, and advise what PPE to have on hand.

The good news is that this is entirely rational and reasonable, and it will save lives and reduce injuries.

The bad news is that it may also: (1) allow hazardous conditions that would not otherwise exist; and (2) give everyone a false sense of security.

Regarding bad news (1): without having done the incident energy analysis (engineering) and identifying the hazards involved with energized work, many owners and managers historically have simply prohibited work on live parts; but after NFPA 70E engineering, it may appear that it is now safe for employees to work on energized equipment under specific conditions.

Regarding bad news (2): without verifying proper installation and performing preventive maintenance on electrical assets, the calculations may be way off, perhaps with fatal results.

So this is the kernel of the message: owners and managers may be sending technicians into harm’s way as a result of doing arc flash incident energy analysis alone, without preventive maintenance.

The NFPA 70E standard states in section 130.5 Informational Note 1 that “improper or inadequate maintenance can result in increased opening time of the overcurrent protective device, thus increasing the incident energy”. Furthermore, Chapter 2 “Safety-Related Maintenance Requirements” requires that the owner of the equipment shall (no wiggle room here) preserve and/or restore the condition of electrical equipment and installations related to the safety of employees. Why? In sum, OSHA and NFPA’s goal is to avoid 3rd Degree burns that result from exposure to 1.6 calories per square centimeter for 1 second. They (and technicians, literally) can live with 1.2 calories per square centimeter for 1 second, or 2nd Degree burns. But if the actual exposure time increases just a fraction of a second over the calculated time, the technicians will have inadequate PPE and could be severely injured or killed.

Example 1: Discontinuous or inadequate grounding – during a fault, the current will encounter increased resistance, reducing the flow of energy so that it will take longer for the protective device to open, increasing exposure time.

Example 2: Loose connections, poor insulation – reduces the flow of energy so that it will take longer for the protective device to open, increasing exposure time.

Example 3: Dirt (all types), rodents, insects, and corrosion – could conduct current around the protective device, invalidating the engineering analysis.

Example 4: Breaker operation – the electronic trip units should be tested every 3 years (secondary injection) and the mechanics should be tested every 5 years or after a fault (primary injection) to assure that the protective device will operate as designed, thereby validating the engineering analysis.

Summary: It is imperative that NFPA 70E Chapter 2 “Safety-Related Maintenance Requirements”, including verification that electrical components are properly installed, be conducted in conjunction with the engineer’s incident energy analysis to validate the results. Without this, owners and managers may have a false sense of security and send employees into harm’s way without adequate protection against actual hazards. The process to guard against this can be: (1) conduct comprehensive energized preventive maintenance and concurrently collect system data needed for engineering; (2) the CE uses this data to perform breaker coordination and incident energy analyses, create one-lines, and create and apply labels; (3) schedule outage, perform repairs identified during energized preventive maintenance, and conduct de-energized breaker testing. These activities will save lives, prevent injuries, avoid OSHA fines, increase equipment life, improve productivity, and reduce maintenance costs.

By |2018-02-07T15:48:04+00:00January 4th, 2017|Safety and Energy Saving Tips|Comments Off on Deadly Monster Not Tamed by Engineering Alone.