Electrical Equipment Maintenance (NFPA 70B)
Poorly maintained electrical equipment overheats, fails and starts fires. NFPA 70B, Recommended Practice for Electrical Equipment Maintenance, describes how to keep it in good order. Since its 2023 edition, it is a full standard rather than a suggestion.
- Facility Managers
- Electricians
- Industrial
Why maintenance matters
- Loose connections, dust, moisture and worn parts cause heat, arcs and failures.
- A breaker that does not trip as designed can make an arc flash worse. See Arc Flash.
- Scheduled work finds problems before outages, injuries or fires. NFPA 70E also expects equipment to be maintained so it is safe to work on (see NFPA 70E).
Key ideas in NFPA 70B
- An Electrical Maintenance Program (EMP): written, with assigned responsibilities, goals, schedules and records.
- Condition assessment: equipment is rated by its condition (for example, good, needs attention, needs urgent work) so intervals and priorities are based on risk.
- Inventory and labeling: know what equipment you have, where it is and how critical it is.
- Maintenance intervals: set by manufacturer instructions, environment, age and condition.
- Qualified people: maintenance is done by trained and qualified workers using the right test equipment.
Common maintenance tasks
- Infrared thermography (a heat scan) of panels and connections while under load, to find hot spots.
- Cleaning and inspection for dust, corrosion, moisture and damage.
- Torque checks on connections to the manufacturer's values.
- Testing breakers and protective relays to confirm that they trip.
- Insulation resistance and grounding tests where appropriate.
- Keeping drawings and labels current, including arc flash labels.
Do all work using the right lockout and PPE rules. See Lockout/Tagout and Energized Work Permits.
Records
Record what was found, what was done and test results. Trends in readings (for example, a connection getting warmer each scan) help predict failure. Records also support insurance and inspection needs.
Note: NFPA 70B is a consensus standard that is not itself an OSHA rule, though OSHA may refer to it. Check which edition your insurer, employer or authority having jurisdiction uses.
Standards & references
Last updated: