The purpose of this document is to give recommendations for the maintenance of various types of electrical installations, apparatus, and equipment usually found in industrial and large commercial-type installations. Generally speaking, it is recognized that maintenance needs for specific types of equipment is provided by the equipment manufacturer, as well as from a number of other sources. This is the reason why this standard was developed. The purpose was to bring the general guidelines from various sources into one document – NFPA 70B Recommended Practice for Electrical Equipment Maintenance.

The first three chapters are intended to provide a better understanding of benefits, both direct and intangible, that can be derived for a well-administered EPM program. This
recommended practice is confined to preventive maintenance for industrial-type electrical systems and equipment and is not intended to supplicate or supersede instructions that the electrical manufacturers normally provide. Consumer appliances and equipment intended primarily for use in the home are not included.

Chapter 4 addresses planning and developing an electrical preventative maintenance program (EPM). There are four basic steps … (1) compile a listing of all plant equipment and systems; (2) determine which equipment and systems are most critical and most important; (3) develop a system for keeping up with what needs to be done; (4) train people for the work that needs to be done, or contract for the special services that are needed.

This standard covers equipment ranging from substations and switchgear assemblies, to power and distribution transformers; wiring devices; portable electrical tools and equipment. Let’s discuss a few of the items.

Motor control equipment is found in Chapter 9. Make sure that internal heating, cooling, or air conditioning systems functions properly, as designed. Busbar and terminal connections should be checked for tightness, i.e, not being loose, which leads to proper torque requirements. Pay special attention to aluminum connections. Check busbar support insulators and barriers to ensure that they are free of contamination. Look for cracks and signs of arc tracking. Replace defective units. Don’t forget to check control circuit wiring, at the least annually. Visually check for evidence of damage from over- heating or chafing.

I have a surprise for all of you readers. According to Chapter 9, Section 9-3.5, temporary wiring should be removed or replaced by permanent wiring. How many different standards have to remind us to do this? The 1999 National Electrical Code in Section 305-3(d), or the 2002 National Electrical Code in Section 527.3(D) make it very clear that temporary wiring must be removed immediately upon completion of construction, or for the purpose for which it was installed. OSHA has the same requirement in the Construction Standard 29CFR 1926, Section 1926.405(a)(2).

Section 9-4 of NFPA 70B addresses an item that is commonly overlooked. Disconnects, i.e., motor disconnects, when not properly maintained have been known to fail, some- times with catastrophic results. Failing disconnects have led to serious injuries to personnel operating them.

Chapter 11 addresses molded-case circuit-breaker power panels. Section 11-4 recognizes that standard molded-case circuit breakers are not generally equipped with ground-fault sensing and protection devices, therefore, will not normally trip and clear low-level ground-faults, which can do immense damage, including causing fires. Where necessary, special ground-fault sensing and protective devices may be specified and installed as part of the circuit breaker. Maintenance of molded-case circuit breakers is divided into two parts – electrical and mechanical. Remember, there is a trip, and a latch mechanism that need to exercised routinely. Inspection and cleaning is also part of the maintenance.

Chapter 12 addresses ground-fault protection. There two types of protection; (1) ground-fault-circuit-interrupter protection for personnel (Class A, 5 milliampere differential trip);
(2) ground-fault protection for equipment (differential protection more than 5 milli- amperes), with differential trip settings of 10, 20, or 30 milliamperes, or more.

Check your GFCI circuit breakers, receptacles and other devices at the intervals specified by the manufacturer. Tests conducted have shown that a surprisingly large number of ground-fault circuit-interrupters (Class A) fail when tested. The National Electrical Safety Foundation and the Consumer Product Safety Commission jointly issued a “consumer awareness” recommendation to check GFCI’s monthly and after storms.

Chapter 17 of NFPA 79B, addresses portable electrical tools and equipment. Train your people, check and maintain your equipment on a daily basis (as OSHA mandates), repair as necessary. This is also similar to 1999 NEC Section 305-6 (b)(2)(a)(3).

There is much more information in NFPA 79B than what I have outlined in this article; i.e., power quality, UPS systems, cable trays and busways, lighting, rotating equipment, vibration analysis, etc. Please obtain a copy of NFPA 79B for your library.

Conclusion:

The purpose of NFPA 79B is to reduce hazards to life and property that can result from failure or malfunction of industrial-type electrical systems and equipment. Good work practices would promote using this Standard for all electrical equipment, not industrial equipment and systems only. Like all other NFPA Standards, this Standard is not enforceable by itself, however, any company and / or employer can adopt this Standard and choose to voluntarily follow the recommended practices. It is not mandatory, rather, it is a common sense approach to protecting people and property, and prolonging the life of the equipment and systems.

References:

NFPA 70-1999, National Electrical Code, (National Fire Protection Association, Quincy, MA), Section 305-6.

NFPA 70-2002, National Electrical Code, (National Fire Protection Association, Quincy, MA), Section 527-3(D), Section 527-6.

OSHA (Construction Standard), 29CFR 1926. Section 1926.405(a)(2).

NFPA 70E-2000, Standard for Electrical Safety Requirements for Employee Workplaces, (Quincy, MA, National Fire Protection Association).

NFPA 70B-1998, Recommended Practice of Electrical Equipment Maintenance, (Quincy, MA, National Fire Protection Association).

NESF: National Electrical Safety Foundation; “Test and Protect GFCI” awareness campaign.

Steven J. Owen, electrical consultant, has been active in the electrical industry for over 26 years. Owen is certified as a master electrician/contractor in 45 states; as a National Electric Code instructor for continuing education in 25 states; as an OSHA authorized trainer for Construction and General Industry; as an electrical inspector by BOCA, CABO, IAEI, ICBO & SBCCI; as a Chief Code Analyst by SBCCI; as a lightning protection designer, inspector, installer by LPI; as a Power Distribution Engineering Technician by NICET; Principal voting member of CMP-3 of NFPA 70 – NEC; as a member of ABC, ASCET, ASSE, IAEI, NETA, NFPA, NICET, RSES and SBCCI.