Why solar permits get rejected (and how to avoid it)

A residential solar permit rarely fails because the system is unsafe — it fails because a plan reviewer can't find the one thing they're required to check. Most rejections are the same handful of corrections, over and over. Here are the eight that account for the majority of kickbacks, and what a reviewer is actually looking for on each.

1. Rapid shutdown not shown or not labeled (NEC 690.12)

Rooftop PV must reduce controlled conductors inside the array boundary to a safe level (≤ 80 V) within 30 seconds. Reviewers look for a device on the one-line — microinverters, DC optimizers, or a listed PV rapid-shutdown system — plus the initiator and the required label at the service. A note saying "rapid shutdown provided" without a device on the drawing gets corrected. See our 690.7 string-sizing reference for the related voltage math.

2. The 120% busbar rule (NEC 705.12(B))

On a load-side (back-fed breaker) interconnection, main breaker + solar breaker ≤ 1.2 × busbar rating. A 200 A busbar with a 200 A main allows only a 40 A back-fed solar breaker. Exceed it and the fix is a supply-side (line-side) tap, a main-breaker downsize, or a busbar upgrade. We explain it with a by-panel table on the 705.12 reference page.

3. String voltage over the inverter maximum (NEC 690.7)

Cold weather raises a string's open-circuit voltage. Reviewers re-run the coldest-expected-temperature Voc correction and check it against the inverter's max input. Size the string for the record-low temperature, not a nominal 25 °C.

4. Conductor and OCPD sizing (NEC 690.8 / 310.16 / 240.6)

The classic miss is forgetting the stacked 125% factors (1.56 × Isc) or skipping the temperature and conduit-fill derate on a hot roof, then landing on a wire that's fine on paper but under-ampacity after derating. Our 690.8 and 310.16 pages carry the worked math.

5. Grounding and bonding gaps (NEC 250 / 690.47)

A missing grounding electrode system, an undersized GEC (250.66) or EGC (250.122), or no array equipment bonding are frequent corrections. Every system needs a grounding electrode per 250.50.

6. Incomplete site / plot plan

Reviewers want a plot plan (property lines, structures, setbacks, north arrow) and a roof plan (array layout, fire access pathways and setbacks per IFC 605). A roof sketch alone gets bounced.

7. Missing equipment datasheets / unlisted equipment

The module, inverter and racking manual are part of a complete submittal — many AHJs (and California) require listed equipment with the cut sheet attached. Leaving them off is an easy, avoidable correction.

8. Labels and placards (NEC 705.10 / 690.56)

The plaque/directory at the service, the PV system disconnect labels and the rapid-shutdown marking all have to appear on a label schedule. Reviewers check for them explicitly.

None of these are hard to get right — they're just easy to forget on a hand-drawn set. A design that names its rapid-shutdown device, passes the 120% math, sizes its strings cold and carries a real plot plan and datasheets clears plan check on the first pass far more often.

Educational reference, reviewed 2026-07. A design aid, not a substitute for a licensed electrician or PE. Confirm the enforced NEC edition and local amendments with your AHJ.