Understanding Stray Voltage in Pools and Decks

Causes, Risks, and Solutions

Stray voltage, also known as neutral-to-earth voltage or touch potential, refers to unintended electrical currents that can flow between conductive surfaces. While often dismissed as non-lethal, stray voltage poses significant risks in certain environments, such as swimming pools and decks. This blog post explores the causes of stray voltage, its impact on pools, and the evolution of safety measures to mitigate risks.

What Is Stray Voltage?

Stray voltage occurs when electrical systems generate low-level currents due to faults or improper grounding. Common sources include:

• Damaged underground cables
• Leaking pad-mounted transformers
• Faulty pool equipment

These currents follow the path of least resistance, typically favoring wet surfaces over dry ones. This makes environments like pools and wet decks particularly susceptible.

How Stray Voltage Affects Pools

The conductivity of pool materials determines how stray voltage interacts with the body of water:

• Fiberglass and Vinyl Pools: These materials are non-conductive and insulate the water from stray voltage.
• Concrete (Gunite) Pools: Concrete is highly conductive when wet. However, most concrete pools are reinforced with steel rebar grids that act as an equipotential plane. This structure functions similarly to a Faraday cage, preventing stray voltage from entering the pool water.

The Evolution of Pool Decks and Stray Voltage Risks

Pre-1990s Construction Practices
Before the 1990s, pool builders used structural steel grids in both pool shells and surrounding decks to create equipotential planes. These grids ensured both swimmers and pedestrians were protected from stray voltage.

Post-1990s Changes
With the rise of paver decks and fiber-reinforced concrete (fibercrete), builders began omitting steel reinforcement in decks to save costs. While these materials were structurally sufficient, they lacked electrical bonding capabilities, exposing pedestrians on wet decks to stray voltage risks.

Regulatory Interventions

In response to increasing reports of shocks and injuries caused by stray voltage, the National Electrical Code (NEC) introduced Article 680.26 in 2005. This code mandated equipotential bonding grids around pool shells and decks. Builders were required to use metallic grids made from:

1. Welded Wire Sheets

2. Tied Rebar Grids

3. Copper Wire Grids

Despite these measures, some builders opted for single-wire bonding systems in an attempt to cut costs. However, this approach proved ineffective since concrete behaves like dirt—it cannot be bonded without a metallic grid.

Recent Developments

By 2022, mounting evidence highlighted the dangers of inadequate bonding systems:

• A U.S. Coast Guard report documented three deaths due to stray voltage on pool decks lacking proper bonding grids.
• Homeowners in North Carolina reported severe shocks on newly constructed pool decks.

Legal action prompted changes to the NEC in 2023, requiring fully encapsulated metallic grids for all pool decks. The updated code specifies three options for creating equipotential planes:

1. Welded Wire Sheets: Rarely used but compliant.
2. Tied Rebar Grids: Must follow a 12-inch by 12-inch pattern and be fully encapsulated in concrete.
3. Copper Wire Grids: Ideal for paver decks or natural ground surfaces; must be listed products by January 2025. Our recommendation is CMI 3' Wide X 100' Copper Equipotential Bonding Grid With Kit (EB3100).

Our Recommendation

At EZ Pool & Spa Supply, pool safety is a top priority, and we offer the CMI 3' Wide X 100' Copper Equipotential Bonding Grid With Kit (EB3100) as a reliable solution for mitigating stray voltage around swimming pools. This NEC-compliant product is highly recommended by professional pool installers due to its proven durability, effectiveness, and high-quality construction. The EB3100 kit includes everything needed for hassle-free installation, such as UL-listed clamps, split bolts, and metal stakes, ensuring comprehensive protection against stray voltage. EZ Pool & Spa Supply provides free shipping on orders over $99 and is known for excellent customer service, making it a trusted source for pool owners seeking safety and compliance.

Conclusion

Stray voltage is a serious issue that demands attention in pool construction and maintenance. Advances in electrical codes have significantly improved safety standards, but adherence to these regulations is crucial for protecting swimmers and pedestrians from electrical hazards. Whether you're building a new pool or upgrading an existing one, ensure compliance with equipotential bonding requirements to mitigate risks effectively.