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	NFPA 79 Electrical Standard for Industrial Machinery


NFPA 79 Industrial Machinery Metal Workshop	2021
NFPA 70 Article 670 Industrial Machinery	NEC 2020

NEC-2020 The latest release of NEC/NFPA 70 edition 2020 (NEC 2020) has placed a greater emphasis on increasing personnel safety by mandating the use of Surge Protective Devices (SPDs).

From 2014 to 2020, the number articles now requiring SPDs has increased significantly for applications ranging from Modular Data Centers, Fire Pumps, Elevators, Critical Power Systems, Dwellings (Dormatories, Homes, Hospitals, Hotels), etc.

Threat to industrial machines

Various codes and standards possess safety interlock criteria including the American National Standards Institute (ANSI) standards and NFPA 79 for Industrial Machinery. However, until now, these standards have only just begun to address the expanding role that surge protection plays preserving the integrity of equipment and, more importantly, protecting the lives of personnel.

A study commissioned by the Fire Protection Research Foundation, “Data Assessment for Electrical Surge Protective Devices”, provides results of a survey of facility managers concerning surge damage. (NFPA 2014) The study shows that 26 percent of facility managers had damage to safety interlocking systems on industrial machines due to surges . The main purpose of these safety interlocking systems is to protect workers and maintenance personnel from contact with exposed live parts and electric shock. Failure of these devices can put personnel at an increased risk of injury.


CNC lathe

The solution for NFPA 70 and NFPA 79

To make the installation of a Surge Protective Device (SPD) at the industrial machines interlocking safety circuit mandatory which in turn increases the equipments reliability.

[NFPA 70: 2020] Article 670.6 Surge Protection.
"Industrial machinery with safety inter-lock circuits shall have surge protection installed.”

[NFPA 79: 2021] 7.8.1 Surge Protective Devices (SPDs).
"Industrial Machinery with safety circuits not effectively protected from the effects of overvoltages due to lightning or switching surges shall have surge protection installed.” Exception: SPDs shall not be required where the risks associated with the effects of overvoltages are mitigated such that the safety performance determined by a risk assessment is met.

as well as

4.5.2 Electromagnetic Compatibility (EMC).
"Transient suppression, isolation, or other appropriate means shall be provided where the equipment of an industrial machine generates electrical noise or transients, which can affect the operation of equipment that is on or part of the industrial machine."

Selecting an SPD for Industrial Machinery

NEC/NFPA 70 require that Surge Protective Devices (SPDs) shall be UL1449 Listed . This means selecting a surge protector is easier than it has ever been. There are only a few choices available for SPDs that are UL Listed for any of the most commonly used surge standards including UL1449 5th Edition, UL497B, and UL497E.

Recommended SPD for Industrial Machines

Location	Equipment	System	Surge Protector Model#
Service Entrance	Main Service Panelboard	277/480Vac	MDS750E-277Y
Branch Panel	Equipment Panelboard	480Vac	M50-480D-A
Local Equipment	Control Panel	480Vac Power Input	DS74US-480D
	Power Supply	120-240Vac Power Input	DS72US-230S/G
		24Vdc Power Output	DS220S-24DC
	Control Unit	Ethernet Cat 6A	MJ8-C6A
		4-20mA	DLAS-24D3
		Wireless	P8AX09-6G-N/FF

Types of machines covered by NFPA 79

Annex C — Examples of Industrial Machines Covered by NFPA 79

Section	Type	Description
C.1	Machine Tools	Metal Cutting Metal Forming
C.2	Plastics Machinery	Injection molding machines Extrusion machinery Blow molding machines Specialized processing machines Thermostat molding machines Size reduction equipment
C.3	Wood Machinery	Woodworking machinery Laminating machinery Sawmill machinery
C.4	Assembly Machines
C.5	Material-Handling Machines	Industrial robots Transfer machines Sortation machines Conveyors and conveying machines
C.6	Inspection/Testing Machines	Coordinate measuring machines In-process gauging machines
C.7	Packaging Machines	Carton-strapping machines Drum-filling machines Palletizing machines


10108 USA Today Way Miramar, FL 33025 USA	Contact us to develop a surge mitigation solution for your application
www.citel.us	Where to purchase Citel SPD's

Standard and Electric Code References for Surge Protective Devices

Title
NFPA 70 edition 2023, Article 670 Industrial Machinery, 670.6 Surge Protection
NFPA 70 edition 2020, Article 670 Industrial Machinery, 670.6 Surge Protection
NFPA 70 edition 2017, Article 670 Industrial Machinery, 670.6 Surge Protection
NFPA 70 edition 2014, “Data Assessment for Electrical Surge Protective Devices”
NFPA 79 edition 2024, Electrical Standard for Industrial Machinery, Chapter 7, 7.8 Protection Against Overvoltages Due to Lightning and Switching Surges 7.8.1 Surge Protective Devices (SPDs)
NFPA 79 edition 2021, Electrical Standard for Industrial Machinery, Chapter 7, 7.8 Protection Against Overvoltages Due to Lightning and Switching Surges 7.8.1 Surge Protective Devices (SPDs)
NFPA 79 edition 2018, Annex C, Examples of Industrial Machines Covered by NFPA79
ANSI C62.41, Low-Voltage AC Power Circuits
UL1449 5th Edition, Surge Protective Devices
UL1449 4th Edition, Surge Protective Devices
UL497B, Surge Protectors for Data Lines and Fire-Alarm Circuits
UL497E, Antenna Lead-in Conductors
IEC 61643-11, Low-Voltage Surge Protective Devices - Part 11: Surge Protective Devices Connected To Low-Voltage Power Systems - Requirements And Test Methods
IEC 61643-21, Low Voltage Surge Protective Devices - Part 21: Surge Protective Devices Connected To Telecommunications And Signalling Networks - Performance Requirements And Testing Methods
IEC 61000-45, Electromagnetic Compatibility (EMC) - Part 4-5: Testing And Measurement Techniques - Surge Immunity Test
CSA 22.2
NOM-001-SCFI, Standard for Electronic Equipment
NOM-003-SCFI, Electrical Products - Safety Requirements
SEMI S22, Safety Guideline for the Electrical Design of Semiconductor Manufacturing Equipment