Installation codes
| Code | Publisher | Scope |
|---|---|---|
| NEC (NFPA 70) | NFPA | Premises wiring: services, feeders, branch circuits, grounding, equipment. Updated every 3 years; adoption varies by jurisdiction. |
| NESC (ANSI C2) | IEEE | Utility and communication lines: clearances, strength, grounding, work rules. |
| Local amendments | AHJ | State and municipal modifications; the authority having jurisdiction has final say. |
Workplace safety
| Standard | Scope |
|---|---|
| OSHA 29 CFR 1910 Subpart S | Electrical safety for general industry (design and safe work practices) |
| OSHA 29 CFR 1910.147 | Control of hazardous energy (lockout/tagout) |
| OSHA 29 CFR 1910.269 / 1926 Subpart V | Power generation, transmission and distribution work |
| NFPA 70E | Electrical safety in the workplace: risk assessment, boundaries, PPE |
| NFPA 70B | Electrical equipment maintenance. A standard since the 2023 edition. |
Engineering standards
| Standard | Topic |
|---|---|
| IEEE 1584 | Arc flash incident energy calculations |
| IEEE 519 | Harmonic control limits at the point of common coupling |
| IEEE 142 (Green Book) | Grounding of industrial and commercial power systems |
| IEEE 3000 series | Recommended practices for industrial and commercial power systems |
| NEMA MG 1 | Motors and generators: ratings, design letters, unbalance derating |
| ANSI C84.1 | Service and utilization voltage ranges |
| UL 67 / 891 / 1558 / 508A | Panelboards, switchboards, switchgear, industrial control panels |
Energy regulations
The US Department of Energy sets minimum efficiency standards for many electric motors and distribution transformers. Building energy codes, such as ASHRAE 90.1 and the IECC, can require metering, controls and efficient equipment.
Applying the standards
Codes set minimums. Good design often goes further. For practical guidance, see the Safety Handbook and Grounding Three-Phase Systems. We summarize standards for general understanding; always refer to the official current text.