When Checking for Pool Bonding Should You Use Resistance or Continuity
What is Equipotential Bonding for Pools?
The equipotential bonding eliminates voltage gradients which is an increase in voltage potential. Bonding all equipment and metallic parts together is required per 680.26 of the NEC to equalize a difference in voltage potential, which reduces the possibility of electrical shock. If the conductive metallic parts are not effectively bonded together it will create a difference in voltage potential between the conductive parts. A person can become a conductor when they become a part of the conductive path between the conductive parts which can cause an electrical shock. Therefore, equipotential bonding is critical to ensure all conductive parts are at the same voltage potential and to prevent an electrical shock. You can not verify that the Pool Deck or the Pool Shell is Bonded properly by testing the Resistance, but you can verify that all other parts are properly bonded by testing the Resistance. You can verify that the Pool Deck and the Pool Shell is bonded properly with Testing the Neutral-To-Earth voltage measurements, and this Test will also verify that all the other parts are bonded as well.
How do you Test Equipotential Pool Bonding?
First, select the Volt setting on your multimeter and Lead 1 should be 100 ft. long and at least 18 AWG copper and Lead 2 be standard length in order to test the equipotential pool bonding.
Next, established a zero-reference point to remote earth by installing a stake in the ground 50 ft. away from the Electrical Service and anything that's electrically conductive in earth and connect Lead 1 to a stake with an alligator clip. Connect Lead 2 to the the ground bar at the Service Equipment. The Neutral-To-Earth voltage measurement will be our starting reference point, my measurement was 0.86 V.
Now, the following measurements should be the same voltage as remote earth, my measurement was 0.86 V. The Neutral-To-Earth voltage will fluctuate with the Utility Load on the Primary Neutral. First, connect the Lead 1 to the ground bar in Service Equipment for the remainder of the testing and connect the Lead 2 to the pool panel, the measurement was 0.87 V. Now, connect Lead 2 to the pool light transformer, the measurement was 0.89 V. Then connect Lead 2 to the pool motor, the measurement was 0.85 V. Next, connect Lead 2 to the pool junction box outside the lanai, the measurement was 0.91 V. Inside the pool area, connect Lead 2 to the pool lanai which measured 0.88 V. Now, connect Lead 2 to the handrail which measured 0.86 V. Then, connect Lead 2 to the metal on the pool light which measured 0.92 V. This verified that all equipment and all metallic parts is bonded within 5 Ft. of the pool water and has the same potential.
Than, verify if the conductive Pool Shell is bonded properly. First, connect Lead 2 to 4 equal points inside the Pool's Shell along the inside perimeter. The Neutral-To-Earth voltage between the water and all bonded parts was zero, all 4 measurements was 0.86 V - 0.90 V which confirms that the conductive Pool Shell is bonded properly.
Last, verify the perimeter Pool Deck is bonded is bonded properly. First, ensure the Pool Deck is wet. Then, connect Lead 2 to 4 equal points around the Pool Deck perimeter at each of the 4 equal points. Connect Lead 2 and test 6", 12", 18", 24", 30" and 36" from the outer portion of the pool water along the Pool Deck. At each of the 4 equal points along the Pool Deck perimeter, the Neutral-To-Earth voltage was zero, all 4 measurements was 0.85 V - 0.89 V which confirms that the Pool Deck is bonded properly.
Warning: It is recommended that immediate action needs to be taken to reduce Neutral-To-Earth voltage when the NEV at the service entrance or between contact points is higher than the 2 to 4 volts. When the a NEV at a pool is 2 V or more, this can become serious problem if the equipotential bonding of the pool was compromised. Unfortunately, there is no standard for stray voltage and this is only a recommended guideline.
Source: https://www.linkedin.com/pulse/what-equipotential-bonding-pools-how-do-you-test-david-harsche/
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