NFPA 79-2021 PDF

Full title and description

NFPA 79-2021 — NFPA 79, Electrical Standard for Industrial Machinery. This edition establishes safety requirements for the electrical/electronic equipment, apparatus, and systems of industrial machines (nominal supply voltages of 1000 V or less) to protect operators, maintenance personnel, equipment, and facilities from fire and electrical hazards.

Abstract

NFPA 79-2021 provides minimum requirements for the electrical design, installation, and maintenance of industrial machinery electrical systems and control equipment. Topics include wiring practices, grounding and bonding, overcurrent protection, control circuit design, enclosure and access requirements, short-circuit current rating (SCCR) considerations, and coordination with the National Electrical Code (NEC) and related standards. The 2021 edition updates alignments with contemporary NEC requirements and addresses new technologies impacting machine electrical safety.

General information

• Status: Superseded by NFPA 79 (2024) — the 2021 edition remains a published historical edition but has been revised by the 2024 edition.
• Publication date: 2021 (official publication January 2021).
• Publisher: National Fire Protection Association (NFPA).
• ICS / categories: Electrical engineering (ICS 29) — relevant subfields include switchgear & controlgear, components for electrical equipment and rotating machinery (examples: 29.020; 29.130; 29.160).
• Edition / version: 2021 edition (edition referenced as NFPA 79-2021).
• Number of pages: ~107 pages (publisher bibliographic listing).

Scope

Applies to the electrical/electronic equipment, apparatus, or systems of industrial machines supplied from nominal voltages of 1000 volts or less, beginning at the point of connection of the supply circuit conductors to the electrical equipment of the machine. It covers design, installation, and protective measures intended to reduce risk of electrical shock, fire, and equipment damage while coordinating with the NEC and other safety standards.

Key topics and requirements

• Requirements for wiring methods, conductor sizing and termination, and protection against overcurrent and short-circuits.
• Grounding and bonding requirements specific to industrial machinery to minimise shock and fire hazards.
• Control-circuit design, interlocks, and emergency stop and safety-related control considerations.
• Enclosure and enclosure-access rules (including provisions for when access to live parts is permitted), and mechanical/electrical interlocking of doors and disconnecting means.
• Industrial control panel marking and short-circuit current rating (SCCR) guidance for panels and entire machine electrical equipment.
• Coordination with NEC (NFPA 70), NFPA 70E for workplace electrical safety, and with applicable product safety standards (for example UL/CSA requirements for control panels).
• Considerations for surge protection, wiring to variable-frequency drives, and modern control devices.

Typical use and users

Used by OEM machine builders, electrical and controls engineers, plant safety and maintenance personnel, electrical inspectors, and third‑party conformity assessors to design, build, inspect, and maintain safe electrical systems on industrial machinery. It is commonly referenced to demonstrate compliance with recognized good practice and to coordinate machine design with NEC and workplace safety requirements.

Related standards

Commonly cross-referenced standards and documents include: NFPA 70 (NEC), NFPA 70E (electrical safety in the workplace), IEC 60204-1 (Safety of machinery — Electrical equipment of machines), UL 508A (industrial control panels), and relevant CSA standards (e.g., C22.2 series) for Canadian applications. These documents are used together with NFPA 79 to ensure electrical and machine safety across jurisdictions.

Keywords

industrial machinery; electrical standard; wiring; grounding; control panels; enclosure access; SCCR; NEC coordination; machine safety; NFPA 79.

FAQ

Q: What is this standard?

A: NFPA 79-2021 is the 2021 edition of "Electrical Standard for Industrial Machinery," a consensus NFPA standard that sets minimum electrical safety requirements for industrial machine electrical/electronic equipment.

Q: What does it cover?

A: It covers electrical design, installation, protection, marking, and maintenance requirements for industrial machinery electrical equipment (nominal supply voltages up to 1000 V), including wiring methods, grounding/bonding, control circuits, enclosure access, overcurrent protection, and coordination with NEC and other standards.

Q: Who typically uses it?

A: Machine designers and manufacturers, electrical/control engineers, safety managers, maintenance staff, and inspectors use NFPA 79 to design, build, evaluate, and maintain safe machine electrical systems.

Q: Is it current or superseded?

A: The 2021 edition has been revised — NFPA issued a subsequent edition in 2024. NFPA 79-2021 remains a published historical edition but users should consult the 2024 edition for the latest requirements where applicable.

Q: Is it part of a series?

A: Yes — NFPA 79 is part of NFPA's body of electrical and life‑safety standards and is commonly used alongside NFPA 70 (NEC), NFPA 70E (electrical safety in the workplace), and applicable product safety standards (UL/CSA), as well as international machine electrical standards such as IEC 60204‑1.

Q: What are the key keywords?

A: Electrical standard, industrial machinery, wiring, grounding, control panels, SCCR, enclosure access, NEC coordination, NFPA 79.