The question of whether you need an equipotential bonding grid for a stock tank used as a pool, even with a double-insulated pump and sitting directly on the ground, is complex and depends on several factors and interpretations of the National Electrical Code (NEC). While a definitive "yes" or "no" requires a local electrical inspector's ruling, here's a breakdown to help you understand the reasoning and potential requirements

The Argument for Bonding (NEC leaning):
Definition of a Pool

The NEC doesn't explicitly define "pool" based on size or depth alone. If your local inspector considers an 8-foot diameter, 30-inch deep stock tank filled with water for swimming to be a pool, even a temporary one, then pool-specific electrical codes likely apply.

Voltage Gradient and Shock Hazard

Even with a double-insulated pump, a fault elsewhere in the electrical system (e.g., faulty outdoor lighting fixture, a damaged extension cord used nearby) could introduce voltage into the ground. Water is a conductor, and a voltage gradient in the water and surrounding earth can create a shock hazard for someone in or near the pool. Bonding aims to minimize this voltage difference.

NEC 680 (Swimming Pools, Fountains, and Similar Installations)

This section of the NEC provides specific rules for equipotential bonding around pools. While many of these rules deal with permanent in-ground or above-ground pools, some sections could be interpreted as applying to any body of water used for swimming.

NEC 680.26(B)(1)

This section specifically requires a perimeter equipotential bonding grid for permanently installed pools. While your stock tank isn't permanently installed, the question is whether it's considered an "installation" subject to this requirement, particularly if used as a pool for a season or more.

Local Interpretation

Local electrical inspectors have the final say. Their interpretation of the NEC, based on local conditions and experience, is crucial.

The Argument Against Bonding (Reasonable Counterpoints)



Temporary vs. Permanent

A stock tank sitting on the ground that is easy to move and seasonally used is far from the structure and permanence of a traditional pool. NEC articles on pools tend to address fixed structures.

Depth and Contact

The depth of the water (30 inches) may be a factor. The electrical hazard is lower than in a full sized pool.

Double Insulation

Using double-insulated equipment significantly reduces the risk of faults introducing voltage into the water.

Grounding vs. Bonding

It's critical to distinguish between grounding and bonding. Grounding is about providing a path for fault current to return to the source. Bonding is about creating an equipotential plane to minimize voltage differences. The double-insulated pump likely doesn't need grounding, as it's designed to prevent fault currents from escaping. Equipotential bonding addresses a different potential hazard.

Risk vs. Cost

Bonding is labor-intensive and adds cost. The perceived risk for a temporary, small, ground-level stock tank pool might be considered low enough that the cost of bonding outweighs the marginal safety benefit (this is a subjective assessment, however).

What to Do


Consult Your Local Electrical Inspector

This is the most important step. Contact your local electrical inspection department and ask them about the requirements for a stock tank used as a pool in your area. Explain your setup (double-insulated pump, sitting on the ground, etc.) and ask specifically if equipotential bonding is required.2.

Review NEC 680

While the NEC can be difficult to interpret, familiarize yourself with Section 680, particularly the subsections on bonding (680.26).
3.

Consider Mitigation Measures

If bonding isn't required, take other steps to minimize electrical risks: Use a GFCI-protected outlet for the pump. This is essential. Keep all electrical cords and equipment away from the pool. Educate users about electrical safety around water. Consider a "pool noodle barrier" around the water to keep people further away from the side if there are any concerns of shock.4.

If in doubt, bond

Even if not strictly required, err on the side of safety. If you're uncomfortable with the potential risks, or if the inspector gives you a gray answer, consider installing a simplified bonding system. This could involve bonding the pump's metal components (if any) to a ground rod driven into the earth nearby. A professional electrician can advise on this.

Example of a Simplified Bonding System (consult an electrician)

Drive a ground rod into the earth near the stock tank. Bond any metal parts of the pump assembly (check the manufacturer's instructions – some may require bonding) to the ground rod using a solid copper conductor. You could create a simple "perimeter" by burying a ring of bare copper wire a foot or so away from the tank, connected to the ground rod. This is less effective than a full grid but may provide some level of equipotential bonding.

Important Considerations



Double-Insulated Pumps

While double-insulated pumps are safer, they don't eliminate all risk. A fault outside the pump can still introduce voltage into the water.

DIY vs. Professional

Electrical work can be dangerous. If you're not comfortable working with electricity, hire a qualified electrician.

Liability: Even if the inspector doesn't require bonding, you're still responsible for ensuring the safety of anyone using the pool.In summary, while a strict interpretation of the NEC might suggest bonding, the specifics of your setup (double-insulated pump, non-permanent nature of the stock tank, etc.) and your local inspector's interpretation will determine the actual requirements. Contact the inspector first. Then, weigh the risks and benefits and choose the safest course of action. Flag for review