Which of the following is a method for bonding an indoor spa or hot tub?

The method for bonding an indoor spa or hot tub involves ensuring that all metal parts are electrically connected and at the same electrical potential to prevent electric shock hazards. Each of the listed methods contributes to this objective in different yet complementary ways.

Using a bonding grid is particularly effective as it involves creating a network of conductive materials that connect various components of the spa or hot tub. This grid helps to mitigate the risks of stray currents and potential differences between surfaces.

Connecting to the house grounding system ensures that the spa or hot tub is part of the overall electrical safety plan of the home. By bonding to the existing grounding system, any faults can be redirected safely, enhancing protection against electrical hazards.

Installing a ground fault circuit interrupter (GFCI) is essential in providing an additional layer of safety. A GFCI detects any imbalance in electric current and quickly cuts off power to prevent serious shock injuries.

Since all these methods serve to enhance safety and compliance with electrical codes, the correct answer indicates that any of these methods can be valid for bonding an indoor spa or hot tub. Therefore, the most comprehensive answer acknowledges that using a combination of these approaches is an effective strategy for ensuring electrical safety in such installations.