Surge Protection for Car Wash Tunnels 

NFPA 79 Industrial Machinery in a Car Wash Tunnel

The latest release of NEC/NFPA 70 edition 2026 (NEC 2026) has placed a greater emphasis on increasing personnel safety by mandating the use of Surge Protective Devices (SPDs).

From 2014 to 2025, the number of articles now requiring SPDs has increased significantly for applications ranging from Modular Data Centers, Fire Pumps, Elevators, Critical Power Systems, Dwellings (Dormitories, Homes, Hospitals, Hotels), etc.

Threats to Car Wash Tunnels

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 surveyed observed 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.

Tunnel Wash Controls

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 equipment's reliability.

NFPA 70 Article 670.6 Surge Protection "Industrial machinery with safety circuits shall have overvoltage protection.”

NFPA 70 Article 409.70 Surge Protection "Safety circuits for personnel protection that are subject to damage from surge events shall have surge protection installed within or immediately adjacent to the control panel."

NFPA 79 Article 7.8.1 Surge Protective Devices (SPDs) "Industrial machinery with safety circuits shall have SPD(s) to protect against the effects of overvoltages due to transients or switching surges. The type of SPD(s) shall be selected to protect, at a minimum, the safety circuit devices and shall be permitted to be integral to secondary derived voltage sources.”

Selecting an SPD for Industrial Machinery

NEC/NFPA 70 require that SPDs shall be UL 1449 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 UL 1449 5th Edition, UL 497B and UL 497E.

Recommended SPDs for Industrial Machines

Location	Equipment	System	Surge Protector Model#	Link
Service Entrance	Main Service Panelboard	277/480 V ac	MDS750E-277Y
Branch Panel	Equipment Panelboard	480 V ac	M50-480D-A
Local Equipment	Control Panel	480 V ac Power Input	DAC104US-480D
	Power Supply	120-240 V ac Power Input	DAC102US-230S/G
		24 V dc Power Output	DS220S-24DC
	Control Unit	Ethernet Cat 6A	MJ8-C6A
		4-20mA	DLA-24D3
		Wireless	P8AX09-6G-N/FF

Standard and Electric Code References for Surge Protective Devices