It’s no secret that the safest place to stay during a lightning storm is indoors. In fact, a home or other substantial structure like an office building serves as the best protection from a lightning strike.
However, no residential home is immune to the threat of lightning strike damage. As more technology is added to residential houses (think TVs, computers, alarm systems or appliances), the risk strikes and electrical surges pose to homeowners is rising.
While methods like surge protectors may reduce the likelihood of damage to the interior of the home, a lightning protection system safeguards the entire structure—inside and out.
To ensure a residential home is adequately protected from the damaging effects of lightning strikes, residential contracts should consider the four components of a lightning protection system.
A Lightning Strike Risk Assessment for Residential Homes
Some homes have a higher chance of attracting lightning than others. Namely, chances are increased based on height and proximity to other houses. (Close proximity being defined as within a distance of three times the height of the home.)
Use the below risk assessment benchmarks to determine how susceptible a residential home is to lightning strikes:
- Low risk: Single-level residences that are surrounded by other homes of a similar height.
- Medium risk: A double-level home surrounded by homes of similar heights or a single-level home that is surrounded by houses of smaller heights.
- High risk: Isolated homes that are not surrounded by other structures, or double-level homes that are surrounded by houses of smaller heights.
No matter the likelihood of lightning strikes, when used properly the four components below will help safeguard any residential house from damage.
Install a Lightning Protection System with These Four Essential Parts
1. Air Terminals
A structure with a high probability of lightning strikes requires an air terminal, as this component’s function is to capture the strike. Based on the shape and size of the structure, keep these design rules in mind:
- Place air terminals on all roof projections, like chimneys.
- Extend terminals at least 10 inches above the roof-line.
- Brace any air terminal greater than 24 inches in height.
- Install air terminals within two feet of a roof ridge or within two feet of outside edges or corners on flat roofs.
2. Interconnecting Conductors
A conductor works together with an air terminal to redirect the electrical path of a lightning strike to the ground, rather than to the structure. On a residential home, follow these installation tips:
- Install down conductors from the roof to the ground level at opposite ends of the home. No less than two conductors should be installed.
- Remember that there must be at least two conductor paths that lead to the ground from each air terminal.
- Bond metallic rooftop objects like gutters or vents to the conductor system.
When choosing the right down conductor, understand the product may be either copper or aluminum. Also, check that the conductor is UL listed for its application (look for the “UL” logo).
3. Electrical Equipment Protection
While direct lightning strikes to the exterior of a home can be the most catastrophic, damage to electrical equipment is also possible. Even a strike that is several hundred feet away can trigger a power surge to electric or telephone lines, or other incoming conductive lines like cable TV or satellite dishes.
Install a hardwired surge protector on the electrical panel to protect electrical equipment within the home.
4. Grounding System
A grounding system is required at a residential home in order for a lightning strike to be discharged into the ground. A grounding system typically includes a copper-bonded ground rod that is installed in the ground.
When installing lightning protection grounding system at a home, follow these requirements:
- Ground electrodes should be at least one-half inch in diameter by eight-feet long.
- Copper-bonded electrodes are recommended.
- If rocky soil or underground service lines prohibit the use of a vertical electrode, a horizontal conductor is needed. It should be buried at least 18 inches below the ground and extend no less than 12 feet away from the home.
- Grounding systems should be interconnected using the same size conductor.
- Interconnecting bonds are required for all underground metallic-piping systems, like water or gas pipes, within 25 feet of the home.
- If all services were already bonded prior to the lightning protection installation, it’s only required to bond the nearest lightning protection ground electrode to the water pipe system.
Want more information on lightning protection for residential homes? Read our full report, “Residential Lightning Protection & Surge Protection,” and visit our website for a list of lightning protection products.
Image credit: Pixabay, CC0 Public Domain