What is stray voltage & why should you be concerned?

It's crucial to understand what stray voltage is and why it should be a significant concern. If you have ever experienced a shock from your pool deck, you may have already encountered stray voltage, and you likely understand why it's crucial to prevent it. However, if you have been fortunate enough to avoid it, it's still essential to understand the potential danger it can pose to swimmers. Stray voltage can even be fatal, underscoring the critical need for pool contractors to prioritize safety. This article will explore the causes of contact voltage and provide practical solutions for addressing this issue.

Stray voltage occurs when voltage exists in the ground. Meaning loose electricity has “escaped” from a cable, a transformer, or other power source. It’s now traveling through the ground, trying to dissipate. Realize that the natural path for electricity is the earth and it tends to flow into the ground (think of a lightning strike).

Following the path of least resistance, the electricity will tackle whichever target is easiest. So, when you have moisture (wet dirt, or say, a pool deck), the electricity will instead travel through that conductive material before dissipating into the ground. Wet concrete would be much easier for it to travel through than the natural ground!

There are ways to prevent against it, but first let’s find out why it can occurs in the first place!

What Causes Stray Voltage?

Stray voltage comes from many sources, such as:

Cuts and nicks in buried lines

Faulty “drops” from overhead power lines (where power comes to a home from the main line). Damaged pads underneath transformers causing power “leaks” and numerous other sources. The fact is, these voltages exist in the ground all throughout America. Even if your home’s electrical is perfectly up to code, you could still be at risk from nearby sources.

How to Prevent Stray Voltage Since 

You can’t possibly stop all the ways stray voltage is caused, you need to stop it from ever reaching you.

How Can I Protect Pool Areas From Stray Voltage?

There are several ways that your pool deck can proof against stray voltage. One of the best ways to get peace of mind is with equipotential bonding. This is essentially a copper wire grid that gets installed in the concrete deck and will attract any contact voltage, keeping the wet ground (and those on it) safe from the risk of shock. Read more about the Electric Power Research Institute's (EPRI) testing report on equipotential bonding configurations for in-ground swimming pools.

To achieve uniform voltage throughout a pool and prevent the risk of electric shock, equipotential bonding is the most effective method. Any presence of voltage differences, no matter how slight, can lead to shocks. As the voltage differences increase, so does the level of danger, potentially causing severe harm. In some cases, the voltage present on a pool deck, in a pool, or spa can be strong enough to cause fatal injuries. Therefore, it's crucial to prioritize equipotential bonding to ensure swimmers' safety.

Why Haven’t I Heard About Stray Voltage Before?

In years past, metal rebar was installed in all concrete flooring as standard practice (for concrete stability). As a result, electricity would choose to flow through metal rather than concrete, and stray voltage wasn’t really a concern in those days.

The introduction of alternative materials into concrete mixtures and the discontinuation of rebar usage in the industry has led to the emergence of stray currents. Unfortunately, this development has resulted in numerous cases of injuries and even fatalities caused by contact voltage.

Protect swimmers and make the area safe by using equipotential bonding grids and mitigate the risk of stray voltage.