A lightning protection system protects structures from direct lightning strikes. The system intercepts the strike and provides a safe, conductive path for the electrical discharge. It then disperses that energy harmlessly into the ground. The system doesn’t prevent strikes but controls them instead.

A complete system includes:

• Air terminals (lightning rods): These components sit on the highest points of a structure to intercept lightning.
• Conductors: Special cables connect the air terminals to the ground.
• Grounding: Ground rods or plates dissipate the lightning’s energy into the earth.

When lightning strikes, the system’s air terminals and conductors provide a low-resistance path for the electrical current. This directs the lightning’s energy away from the structure and its contents. The system safely channels it into the ground, preventing fires and structural damage.

Installing a lightning protection system requires specific training and expertise. Most general electricians, contractors, or roofers lack the necessary knowledge or certification. You should only hire a contractor certified by a recognized organization. The Lightning Protection Institute (LPI) certifies qualified professionals. This ensures the system meets safety standards.

Lightning protection isn’t mandatory for every building. However, local building codes often require it for specific types of structures. These include buildings in areas with frequent thunderstorms and those taller than surrounding structures. Critical service buildings like hospitals, data centers, or emergency services also need protection. Buildings that house large groups (schools, stadiums) require systems. Structures containing flammable or explosive materials need protection. Museums housing irreplaceable cultural heritage must have systems. Taller buildings with metal frames or cladding also require protection.

International standards like IEC 62305 define Lightning Protection Levels (LPLs). A risk assessment determines the appropriate LPL. Each level corresponds to specific protection against lightning strikes. Higher levels (like LPL I) provide greater protection. They handle more severe lightning currents. The assessment determines the system’s design, including air terminal and conductor placement.

A specialist should inspect and test your lightning protection system at least once a year. Regular inspections ensure all components work properly. Specialists check for loose connections, corrosion, or other damage during these inspections.

A surge protection device (SPD) protects against voltage spikes or electrical surges. It limits transient voltages by diverting or limiting excess current to the ground. This prevents surges from reaching and damaging sensitive electronic equipment. SPDs form a key part of comprehensive lightning protection plans. Lightning can cause powerful surges even without a direct strike.

Surge protection devices contain a non-linear component, most commonly a Metal Oxide Varistor (MOV). During normal operation, the MOV maintains very high electrical resistance. It acts as an open circuit, allowing electricity to flow through your system. When a voltage surge occurs, the SPD’s internal components quickly switch to low resistance. This diverts the excess energy safely to the ground. Once the surge passes, the SPD returns to its high-resistance state.

In many regions, yes. Building codes and regulations now mandate SPD installation. The National Electrical Code (NEC) 2020 in the U.S. requires them. The 18th Edition Wiring Regulations (BS 7671) in the U.K. also mandate SPDs for new residential and commercial buildings. The need for surge protection grows as modern homes and businesses use more sensitive electronics.

You should consider installing surge protection in several situations. Install it during new construction or major renovation projects. Consider it if you live in an area with frequent thunderstorms or grid fluctuations. Use it to protect sensitive and expensive equipment like computers, servers, and high-end home entertainment systems. Homes with smart appliances, solar panels, or EV chargers particularly need protection. These systems face greater vulnerability to surges.

A comprehensive approach uses layered defense. Whole-house surge protection serves as your first line of defense. Install it at your main electrical panel to protect all appliances and electronics from external surges. Point-of-use surge protection provides a second layer. These surge protector power strips or outlets protect specific, sensitive equipment like computers, TVs, and entertainment systems.

A whole-house surge protector is highly recommended for houses. The specific rating depends on your home’s electrical service size and electronics quantity. Manufacturers rate whole-house SPDs in kiloamps (kA). This indicates how much energy they can absorb. A 40kA to 80kA rating suffices for most average-sized homes. A 100kA to 120kA rating works better for larger homes or those with many valuable electronics. A licensed electrician can assess your needs and recommend the best surge protection solution for your home.