HVAC Procedure and Performance Guide

TASK : Determine if available electrical service is adequate.

Training for this procedure can be found in these courses:

                         111 – HVACR Electrical DC Theory Plus   and   112 – HVACR Electrical AC Theory Plus


Amperage requirements for both new equipment to be connected and existing equipment already connected must be calculated.  The total amperage required must be compared to the electrical service available.


  1. Determine power requirements (voltage, hertz, amperage and phase) from equipment rating plate data or from manufacturer’s specifications.
  2. Inspect electrical service panel and determine if voltage and phase requirements are met.
  3. Note service entrance main circuit rating in service panel.
  4. Determine total amperage rating of existing circuit breakers.
  5. Determine size and rating of circuit breaker needed for new equipment.
  6. Determine if space is available in service panel for required circuit breakers.
  7. Estimate if existing main circuit breaker will handle existing and proposed amperage loads.
  8. Document findings.