Path-Q Solar

How should I proceed if solar quotes disagree about whether my electrical service can support the system?

Answer

Do not choose based only on the lower quote. Ask each installer to state the service-capacity calculation, assumptions, proposed connection point, and any required upgrades, then seek an independent review from a qualified electrical professional or the relevant utility or network provider before committing.

Key points

  • Compare the actual system size, inverter configuration, service rating, panel capacity, and proposed connection method in each quote.
  • A disagreement may result from different assumptions about existing loads, equipment ratings, connection rules, or future expansion.
  • Require a written explanation of who pays for upgrades, redesign, utility studies, and delays.
  • Separate preliminary installer opinions from formal approval by the responsible authority or provider.

What it depends on

  • Existing service rating and electrical equipment condition
  • Proposed system size, inverter type, batteries, and connection location
  • Existing and planned electrical loads
  • Applicable utility, network, electrical, and interconnection requirements

Risks and trade-offs

  • Ignoring the issue can cause rejection, redesign, equipment damage, safety risks, or unexpected upgrade costs.
  • An upgrade may improve future capacity but add cost, time, and coordination requirements.
  • A smaller system may avoid an upgrade but produce less energy or limit future electrification.

Information you may need

  • Service and distribution equipment ratings, photos, and single-line information
  • Detailed designs and calculations from each installer
  • Existing and planned major loads
  • Written confirmation of any required approval or upgrade and its responsible party

Your next step

What to do next

Request written calculations from both installers and obtain independent electrical or utility confirmation before selecting a design.

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Some details may depend on your location, installer, utility, incentives, regulations, or specific property.

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