Electrical Maintenance Practices that Impact Safety

Proper engineering on the front end of a project, including acceptance testing and commissioning prior to initially energizing, ensures a smooth start up and reduces the problems that can keep a facility from coming on line. Many studies also have shown that routine maintenance, including testing of electrical distribution equipment, has increased reliability and minimized downtime for commercial and industrial facilities.

The same can be said about protecting electrical workers who operate or work on energized electrical equipment, as we now can calculate that the incident energy produced by an arcing fault is proportional to its operating time. This aspect of incident energy means that proper maintenance and testing of over-current protective devices (OCPD) not only is an operational issue, but also a safety issue.

OSHA regulations and NFPA requirements for a qualified electrical worker emphasize the need for safety and skills training for electrical and non-electrical workers. An electrical worker may be experienced, but may not meet OSHA's definition of a qualified person if he or she lacks the safety training and skills required by 29CFR1910.332 and .333.

Tasks with the highest propensity for incidents are related to energized tasks such as troubleshooting (24 percent), operating electrical equipment (19 percent) and repairing components (18 percent). Maintaining electrical equipment only accounts for 5 percent of electrical incidents, as the equipment generally is de-energized to perform scheduled maintenance. Most of these incidents are due to workers not checking for the absence of voltage — or other oversights — before attempting to perform maintenance on the equipment.

NFPA 70E SAFETY-RELATED MAINTENANCE

The NFPA 70E Committee states that an electrical power system must be properly designed, properly installed and properly maintained in order to be considered safe to operate or to maintain. Article 200 (Introduction & Scope) in Chapter 2 of NFPA 70E offers general requirements for safety-related maintenance, but does not give any specific details about the methodology for performing electrical maintenance or the frequency to which the different vintages, manufacturers and protective devices should be maintained.

This largely is left up to the employer to develop and implement, based on manufacturer's instructions, literature and industry standards, as well as equipment condition and the facility's reliability requirements. These NFPA 70E requirements and procedures do, however, establish the requirement for a maintenance program that positively impacts safety for the electrical worker:

• Article 200.1 (1) — “These requirements identify only that maintenance is directly related to employee safety during activities such as installation, operation, maintenance and demolition activities.”

• Article 200.1 (2) — “Chapter 2 does not describe specific maintenance methods or test procedures. This is left up to the employer to choose from the various maintenance methods available to satisfy the requirements of Chapter 2.”

NFPA 70E references two national consensus documents: NFPA 70B — The Recommended Practice for Electrical Equipment Maintenance — and ANSI/NETA MTS-2007 — the Standard for Maintenance Testing Specifications — when discussing proper and safe maintenance of electrical equipment. In addition, two articles establish that a qualified worker is required to preserve and restore the equipment:

• Article 200.1 (3) — “For the purpose of Chapter 2, maintenance shall be defined as preserving or restoring the condition of the electrical equipment and installations for the safety of employees who work on, near or with such equipment. This maintenance directly impacts the proper functionality of the over-current protective devices and circuit breaker mechanical components, as well as any insulating systems and protective barriers.”

• Article 205.1 Qualified Persons — “Employees who perform maintenance on electrical equipment and installations shall be qualified persons as required in Chapter 1 and shall be trained in, and familiar with, the specific maintenance procedures and tests required.”