National Electrical Installation Standards

Standards as High as Your Own

Wednesday, July 10, 2019


Hi, I have an underground tank with a pump inside the tank installed. It was found that the tank was not adequately isolated from other metallic structures in the area. Two wires from the pump were bonded to the tank. If a Solid State Decoupler is installed on the ground level to route grounding wire thru from the pump inside the tank to the earth, is it code compliant? Or is it a code violence? I assume basically decoupler is a capacitor. Thank you

Hyunmin Oh


Hey Hyunmin thanks for your question. Its not clear what you mean by 2 wires being bonded to the tank but if there is a pump in the tank it needs an effective ground fault current path back to the source. This is usually accomplished by using an equipment grounding conductor and equipment bonding jumpers if necessary, as required by 250.110, 250.112, and 250.134? A connection to the earth is not enough, with or without a decoupler. See also 250.4(A)(4) and (5).

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