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Topic: Stray voltage at pool

User: Randal Vincent

Asked on: Thursday, July 3, 2025 at 6:47 am EDT
Answered on: Thursday, July 3, 2025 at 6:48 am EDT

Question: Looking to see if anybody has any information on how to correct this. utility company contacted me in regards to a stray voltage customer had noticed at his above ground pool. Utility company shut power off at the house and claims they were still getting a reading of .04 V from the water and water bond at the skimmer. We're guessing a stray voltage from the ground. Utility company claims when the ground wire is disconnected from the skimmer bond. The voltage is no longer present. Utility company claims they've done everything on their end to correct any stray voltage from Grid?How can I feel comfortable tell the customer that this is OK?

This is a serious situation and you're right to be concerned. Even a small voltage can be dangerous in a pool environment. Here's a breakdown of the issues and how to approach this

Understanding the Problem
Stray Voltage

This is unwanted electrical potential difference that can occur in the ground, water, or metallic objects. It can originate from various sources:


Utility Grid Issues

Failing neutrals, insufficient grounding, voltage imbalances. The utility company says they've checked, but it's worth a deeper dive.

Customer's Wiring

Poorly grounded circuits, insulation breakdown, equipment malfunctions (pool pump, lights, etc.)


Neighboring Properties

Electrical issues on adjacent properties can contribute via shared grounding systems or underground infrastructure.

Corrosion

Galvanic corrosion can create small voltages between dissimilar metals in contact with water.


.04V Significance

While seemingly small, 0.04V in water can be perceptible and potentially dangerous. Water significantly lowers resistance to electrical current, and even low voltages can cause tingling sensations, muscle cramps, or even paralysis in susceptible individuals, especially children.

Ground Wire Disconnection

The fact that disconnecting the ground wire from the skimmer bond
removes the voltage strongly suggests a path for current is being created. The ground wire is supposed to be at or near zero potential. The presence of voltage indicates a fault somewhere that is driving current through the ground.

Why You Shouldn't Feel Comfortable Saying "It's OK"
Liability

If you tell the customer it's okay and something happens, you could be held liable.

Safety

The most important reason. Even low voltage can be dangerous, especially in a pool.


The Problem Isn't Solved

Removing the ground wire doesn't solve the problem, it just hides it. The underlying fault is still present. It is akin to taking the batteries out of a smoke alarm when the house is on fire.

Code Violations

Likely violates electrical codes related to grounding and bonding.

Steps to Take (Detailed)
1. Document Everything

Precisely record the utility company's findings, their actions, and who you spoke with. Document the voltage readings you're observing. Take photographs of the pool bonding, grounding, electrical panel, equipment, etc. Make sure the customer signs off and is aware of the situation.2.

Independent Electrical Inspection (Essential)



Hire a Licensed Electrician Experienced in Pool Stray Voltage Issues.
This is not just any electrician. They need specialized knowledge of pool bonding and grounding. Insist on a comprehensive inspection, including



Ground Resistance Testing

Measure the resistance of the grounding electrode system to earth. Should be very low (ideally 25 ohms or less, often much lower).

Continuity Testing

Verify the integrity of the bonding system (all metal parts are electrically connected).


Insulation Resistance Testing (Megger Testing)

Test the insulation of all pool equipment wiring to detect insulation breakdown, which can leak current into the ground.

Ground Fault Circuit Interrupter (GFCI) Testing

Ensure all pool circuits are protected by properly functioning GFCIs.


Voltage Drop Testing

Assess if there is excessive voltage drop in the branch circuit, and ensure the wire size is correct for the load.

Ask the electrician to provide a written report with their findings and recommendations.
Request that the customer be present during the inspection so the electrician can explain their findings to the customer directly. The electrician should check bonding between pool rebar and skimmer as well.3. Communicate with the Utility Company (Again)

Inform them that you have engaged an independent electrical inspection. Share the electrician's findings with the utility company. They may need to coordinate to further investigate potential grid-related issues. Document all communication with the utility company.4.

Investigate Customer's Equipment



Pool Pump

A failing pump motor can leak current.


Pool Lights

Check for water ingress into the light fixture or conduit.

Heater

If applicable, inspect the heater for grounding issues.


Anything Electrical Near the Pool

Outdoor speakers, outlets, etc.5.

Check Bonding Grid

Ensure that all metal parts of the pool structure (ladder, handrails, diving board supports, etc.) are properly bonded together. This is usually done with a solid copper wire (typically #8 AWG) that encircles the pool. Check the connections to ensure they are tight and corrosion-free. Check the rebar bonding if it exists.6.

Galvanic Corrosion

If the pool has different types of metal in contact with the water (e.g., copper pipes connected to a steel ladder), consider galvanic corrosion as a potential source of voltage. A sacrificial anode might be necessary. This is less likely but should be considered.7.

NEVER Remove the Ground Wire

Removing the ground wire is not a solution and can create a more dangerous situation. The ground wire is there to provide a low-resistance path for fault current to trip a circuit breaker, protecting people from shock.8.

Consider Water Source

If the pool is filled from a well, the well casing and pump should be bonded to the pool's grounding system. The well water can carry voltage from underground sources. Ask the customer about well water.

Explaining to the Customer (Carefully)
Emphasize Safety

"Your safety and the safety of your family and friends is our top priority."

Explain the Problem

"There is a small voltage present in the pool water that we need to investigate further. Even though it's a small amount of voltage, it could potentially be dangerous."


Explain the Investigation

"We are hiring a qualified electrician specializing in pool stray voltage to conduct a thorough inspection of the pool's electrical system."

Explain the Utility Company's Role

"We are also coordinating with the utility company to ensure that the source of the voltage is not coming from their system."


Explain the Importance of Not Using the Pool

"Until the issue is resolved and the electrician has confirmed that the pool is safe, please do not use the pool."

Be Transparent

"We will keep you informed every step of the way and will provide you with the electrician's report and recommendations."

Key Considerations
Local Electrical Codes

Be intimately familiar with your local electrical codes regarding pool bonding and grounding.

National Electrical Code (NEC)

The NEC (specifically Article 680) provides comprehensive guidelines for pool electrical safety.


Professional Advice

Always consult with qualified professionals (electricians and potentially engineers) for advice and guidance.

In Summary


Do not tell the customer it's okay. This situation demands a thorough investigation by a qualified electrician specializing in pool stray voltage issues. Communication and transparency with the customer are essential. The priority is ensuring the safety of everyone using the pool. Flag for review

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