Pool Electrical Calculator

A gas heater draws only about 5A at 240V (just enough to run its ignition control), while a heat pump's compressor draws roughly 40A -- an eightfold jump between the two heater types. Since both feed directly into Total connected load (amps) and Sub- panel size (amps), switching heater type produces a much larger swing than fine-tuning a continuous input like Pump motor (HP) within its normal range.

They come from two different calculations. Total connected load (amps) is the raw sum of every circuit's amperage. Sub-panel size (amps) starts from a related but distinct total that applies the NEC's 125% continuous-duty safety factor to motor loads (pump, heater compressor, spa blower) before snapping up to the nearest standard panel rating (60, 100, 125, or 200A) -- so the recommended panel size is sized with a safety margin the raw connected-load figure does not include.

No -- Wire run to main panel (ft) only determines Bonding Wire (#8 Cu, ft), the equipotential bonding conductor length, which scales with the physical distance to the pool. Pump circuit (amps), Heater circuit (amps), Total connected load (amps), and Sub- panel size (amps) are all determined purely by which equipment is connected and its electrical draw, independent of how far the wire has to run.

12V LED lights run through a low-voltage transformer and draw only about 0.4A at 120V per light, while 120V incandescent fixtures draw roughly 2.5A each directly off the line -- more than six times as much per light. Both get converted to a 240V-equivalent figure before being added into Total connected load (amps), so a pool with several incandescent lights can add meaningfully more load than the same count of LED fixtures.