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Electrical Panel Capacity Calculator
Spare service capacity after adding a water heater, with the 125 percent continuous factor and the next standard service rating.
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Installation calculators
Check the electrical supply, breaker, conductor, and load a water heater installation needs.
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Home Electrical Load Calculator (NEC 220.82)
Dwelling service load by the NEC 220.82 optional method, from floor area, circuits, fixed appliances and HVAC.
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Voltage Drop Calculator
Voltage drop in volts and percent for a run, from the circular-mil formula with NEC Chapter 9 Table 8 areas.
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Water Heater Breaker Size Calculator
Standard breaker rating from the load, checked against the NEC 310.16 ampacity of the conductor and the 240.4(D) small-conductor limits.
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Wire Ampacity Calculator (NEC Table 310.16)
Allowable ampacity by conductor size, material and termination column, with the adjustment factors you applied.
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Wire Size Calculator
Conductor size from the larger of the voltage-drop limit and the NEC 310.16 ampacity limit, for copper or aluminum.
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