Protecting Municipal Facilities from Lightning and Power Surges

Guest post by Marc Dunker, LMCIT senior loss control consultant

Lightning protection is not just about preventing a fire — it’s about keeping essential city services running. From server rooms, emergency communications, to water and wastewater systems, a single surge can disrupt critical operations.

A comprehensive protection strategy requires a multi-layered approach that addresses direct strikes and internal surges.

1. Structural Defense: Lightning Protection Systems

The first line of defense is an external lightning protection system (LPS), designed to intercept a direct strike and safely channel it to the ground.

• Air terminals (lightning rods): Installed at high points, air terminals provide a safe path for lightning current. They do not “attract” lightning but instead provide a preferred attachment point and safely conduct lightning current to ground, reducing the risk of structural damage.

2. Electrical System Grounding & Surge Protection

While rods protect the structure, internal electronic networks require specialized Surge Protective Devices (SPDs) and robust grounding.

Layered Surge Protection:

• Type 1 SPDs: Installed at the service entrance to handle high-energy surges from lightning
• Type 2 SPDs: Located at main distribution panels to protect against switching surges and residual lightning energy
• Type 3 SPDs: Point-of-use protection for sensitive electronics and computer networks.

Low-Resistance Grounding: The National Fire Protection Association (NFPA) National Electric Code (NEC) permits a grounding electrode resistance of up to 25 ohms, though critical infrastructure and sensitive electronics often require significantly lower resistance (e.g., 5 ohms or less).

3. Critical Bonding: Yellow Jacket CSST

A frequently overlooked vulnerability in commercial buildings is the gas piping system, particularly yellow jacket Corrugated Stainless Steel Tubing (CSST).

• Mandatory Direct Bonding: Standard yellow CSST must be bonded to the building’s electrical grounding electrode system. This is best accomplished by hiring a licensed electrician or gas installer.
• The Goal: Ensure all metal components — plumbing, HVAC, and gas lines — remain at the same electrical potential, preventing dangerous side flashes or arcs that could ignite a fire.
• Why It Matters: A single unbonded pipe or a missing surge protective device can result in equipment damage, service disruption, data loss, or even fire.

For cities, protecting local infrastructure means protecting residents.

Consulting a certified lightning protection professional helps ensure systems are properly designed, installed, and aligned with NFPA 780 and NEC requirements.

Work safely – your community depends on it.

Additional Resource:

Prairie Electric: Why Your Business Needs Commercial Surge Protection