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Standby Generator Size Match

Turn a required kW into the residential or light-commercial size class you can actually buy, with the ATS and breaker that go with it.

Inputs

Inputs and assumptions

Result

Transfer switch size
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Breaker rating at 125%
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Load current
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Nameplate rating needed
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What to check

  • Dealer availability and lead time for the class
  • Fuel delivery capacity for the class you pick

Related calculators

Screening-grade sizing. Manufacturer load-acceptance curves, ISO 8528-5 transient limits, and the adopted electrical code edition govern the final selection; an engineer signs off before hardware is ordered.

Saved calculations

Keep the assumptions with the result.

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