To facilitate nighttime swimming, the Fairway Farms Swim Club has 10 underwater lights that provide illumination for the entire pool. All fixtures are connected to centralized junction boxes with specialized pool grounding blocks. The junction boxes are located near the north and west ends of the pool.
The original fixtures are American Products R-500 BC, rated for a 120V/130V R40 medium base 500 W bulb. The original housings are American Products model CN-5 (or equivalent). Conversion to LED may occur in the future (at which point the entire fixture should be replaced to minimize risk of water leaks).
The pool lights, along with additional circuits providing power receptacles on/near the pool deck and tennis courts are shown in the diagram below. The dashed lines indicate connections only - the actual route of the conduit beneath the ground is not known.
The hot and neutral connections within junction boxes and in the breaker panel are marked with the same identifying letters as shown in this drawing.
The receptacles on the pool deck (circuits A and D) share a 20 A circuit. The receptacle near the tennis courts has a dedicated 20 A feed. Due to the long run and use of #12 AWG wire, some voltage drop should be expected on this outlet is heavy loads are used. Observe that GFCI protection is provided via the in-line units inside the pump house; receptacles themselves to not contain GFCI protection but are GFCI protected.
All pool lights are protected by in-line GFCI devices that cut power in the event of a current imbalance (indicating leakage). As with all electrical systems near a pool, safety is critical. These GFCIs must be regularly tested and inspected. Exposure to moisture and corrosive chemicals (i.e. hydrochloric acid and chlorine) may reduce their service life. Replace as needed.
In a standard incandescent pool light fixture, a spring that rests against the light bulb is intended to cause an intentional short-circuit to the filament in the event of a bulb breakage. This will trip a protective device upstream, preventing the possibility of direct contact of water to electricity.
Replacement of Bulbs
Contrary to popular belief, the pool does not need to be drained to replace a light bulb. The fixture is held into the niche (that mounted into the concrete) by a single screw. During installation, sufficient cord is contained/looped in the niche to allow the fixture to be brought up to the pool deck for service.
Details of the replacement won't be covered here - there are plenty of descriptions and YouTube videos that indicate how this process is done. However, it MUST be noted that replacement of the gasket is mandatory. This minimizes the risk of leaks. Even so, it seems quite likely that a leak will form even with gasket replacement on an old fixture (due to an inadequate seal per corrosion, etc).
Always ensure that power is off prior to servicing a fixture. Never operate incandescent bulbs for an extended period of time out of water; the fixture is designed only to be operated underwater (to prevent overheating).
Upgrades in 2020
There were several updates made to the pool lights in 2020. Additional circuits were added to prevent prior overload conditions (per code, a 20 A circuit cannot support a defined load above 80 %, or 16 A). All GFCIs and switches were replaced as the existing units had significant corrosion due to years of moisture and chemical exposure. The drawing above is the result of significant wire tracing and labeling efforts made during this upgrade.