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360 Papa Commercial PV System Design Review

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Kahului, Maui, Hawaii (interconnection through Hawaiian Electric).

Client

Confidential (Hawaii electrical contractor)

Industry

Commercial rooftop solar

Location

Kahului, Maui, Hawaii (interconnection through Hawaiian Electric).

Dates

April 2026 to June 2026

Team Size

1

Services

  • Engineering review of a commercial PV replacement and upgrade set

  • Consolidated review comments and one coordination call

  • NEC code-compliance checks (overcurrent, grounding, fault current)

  • PE stamp, plus a re-seal after utility comments

Summary

A Hawaii contractor sent MHL a design set to replace an aging rooftop PV array in Kahului with a 147.66 kW DC / 100 kW AC microinverter system under a NEM amendment. MHL reviewed the drawings, sent comments on code and documentation gaps, and stamped the corrected set. MHL re-sealed the set in June after Hawaiian Electric asked for more documentation.

Problem / Objective

The contractor wanted an independent engineering review and PE stamp on a 120/208V, three-phase commercial PV set before submittal. The new system had to export no more than 100 kW under the existing NEM agreement.

Process

  1. Reviewed the plan set: 276 Jinko 535 W modules, 276 Enphase IQ8P microinverters, a 400A PV disconnect, and two 200A subpanels on an existing 600A main distribution panel.

  2. Sent marked-up drawings and a comment letter, including a 2/0 conductor paired with a 200A breaker, which NEC 240.4(B) does not allow to be rounded up from 175A.

  3. Asked for a line-side tap confirmation, a short-circuit analysis, and grounding electrode details to reduce AHJ comments.

  4. Agreed to a contractor note on available fault current, AIC and SCCR ratings, and NEC 110.24 field marking, since the main distribution equipment was existing to remain.

  5. Reviewed the revision (NEC, energy and fire code editions, cable schedule, PV string calculations) and stamped the set.

  6. Re-reviewed and re-sealed the set after Hawaiian Electric comments added a TMK map, legacy system records, UL listings, and Enphase power-limiting documentation.

Payoff / Results (Metrics)

  • Stamped drawings returned the same day the contractor addressed the review comments.

  • Code issues fixed before submittal: breaker and conductor coordination, code edition references, and string calculations aligned to a microinverter system.

  • Hawaiian Electric’s export-limit documentation (75 percent active power limit profile, 99.36 kW total PCS AC nameplate) added without changing layout, system size, or protection.

  • Re-seal completed the day after the revised set arrived.

When this applies

A Hawaii contractor or designer replacing a commercial rooftop PV system under a Hawaiian Electric NEM amendment, particularly with microinverters, a 100 kW export limit, or a line-side connection. It also fits teams that expect utility comments and want a Hawaii-licensed engineer who can review and re-seal quickly.

Testimonial

Assets

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