Most solar permit rejections trace back to the same problem: incomplete or incorrect electrical engineering. The AHJ does not care how fast the installation crew works. If the plan set is missing required electrical detail, the permit goes back, the installer waits, and the schedule slips.
Understanding what electrical engineering is actually required for solar PV permit approval helps installers submit correctly the first time. Here is what plan reviewers look for, why it matters, and how to make sure your documentation meets the standard.
What Electrical Engineering Means in a Solar Permit Set
Electrical engineering in a solar permit set covers everything related to how the system generates, conditions, and delivers electricity to the grid or load. It is distinct from structural engineering, which addresses how the racking attaches to the roof and transfers loads to the building.
The electrical scope includes: string configuration and wire sizing, inverter selection and performance specs, overcurrent protection, grounding and bonding, disconnects, rapid shutdown compliance, and the single-line diagram (SLD) that ties all of it together.
The governing code for all of this is NEC Article 690, which covers photovoltaic systems in detail. Not every jurisdiction has adopted the same NEC edition, which creates variation in what reviewers expect. Knowing the applicable code for each AHJ is one of the most important steps before you draw a single line.
String Sizing and Wire Sizing
String configuration determines how many modules connect in series, which controls open-circuit voltage (Voc) and operating current. Reviewers check that Voc stays within inverter input limits and that wire sizing accounts for temperature corrections and conduit fill.
Common errors include using nominal wire ampacity without applying temperature correction factors, undersizing conductors for continuous loads, and failing to derate for conduit fill when multiple circuits share a conduit. Any of these will trigger a correction request.
Our solar permit design services include full string sizing calculations with temperature deratings specific to the project location. We use site address data to pull the correct design temperature, not a generic national value.
Inverter Specifications and AC Interconnection
The permit set must include inverter documentation that confirms the device is UL-listed, matches the system configuration, and operates within the utility service parameters. For string inverters, this typically means confirming that the maximum AC output does not exceed the capacity of the AC disconnect and interconnection point.
For microinverter systems, reviewers expect documentation of the aggregate AC output current and confirmation that the breaker size and service panel busbar rating accommodate it under the 120 percent rule or the load-side connection rules in NEC 705.12.
If the inverter is replacing an existing model or is part of a retrofit, the replacement must be confirmed compatible with the existing rapid shutdown system if one was previously installed.
Rapid Shutdown Compliance
Rapid shutdown is one of the most commonly mishandled sections of a solar permit set. NEC 690.12 requires that conductors inside the array boundary de-energize within a defined time after shutdown is initiated. The specific requirements vary depending on the NEC edition the AHJ has adopted.
For systems subject to the 2017 NEC or later, module-level rapid shutdown is typically required, which means each module must be controlled individually. String inverters without module-level power electronics (MLPE) do not meet this requirement on their own.
The permit set must document how rapid shutdown is achieved. This includes the shutdown initiator, the MLPE or rapid shutdown device used, and confirmation that the system complies with the applicable edition of Article 690.12. Reviewers in jurisdictions that have adopted NEC 2023 may also require confirmation of labeling requirements under 690.56.
Grounding and Bonding
Grounding and bonding requirements for PV systems cover the equipment grounding conductor (EGC), the system grounding configuration, and the ground fault protection device. For ungrounded systems, which includes most modern string and microinverter setups, the plan set must clearly document the grounding configuration and confirm that the inverter includes ground fault detection.
Module frames, racking components, and enclosures must be bonded to the EGC. The plan set should show the bonding path, the conductor sizing, and the connection method for each component. Reviewers look for continuity: every metallic part in the array must have a documented path to ground.
The Role of a PE Stamp
Many jurisdictions require that the electrical engineering in a solar permit set be reviewed and stamped by a licensed professional engineer (PE). The PE stamp signals to the AHJ that a qualified engineer has reviewed the calculations, confirmed code compliance, and accepts responsibility for the design.
The requirement for a PE stamp varies by state, jurisdiction, and sometimes by system size. Our post on PE stamps for solar covers which jurisdictions require them and what the review process involves. If you are operating in multiple states, tracking stamp requirements by AHJ is essential.
Right Angle Engineering provides PE-stamped electrical plan sets through licensed engineers in all 50 states. We also offer permit drawings and engineering stamps as separate services or together as part of a complete permit package.
How a Complete Electrical Plan Set Comes Together
A permit-ready electrical plan set includes: the single-line diagram, string sizing calculations, inverter specification sheets, rapid shutdown documentation, grounding and bonding schedule, and any required PE stamp with engineer of record information.
The single-line diagram is the most visible part of the electrical submittal. It must show the complete circuit from modules through the point of interconnection. Our post on solar plan sets explained covers what plan sets include and how each component supports the permit review.
Before submitting, verify that the SLD matches the spec sheets, that all component models shown on the diagram match the actual equipment being installed, and that the grounding schedule accounts for every metallic component. AHJ reviewers cross-reference these sections against each other.
What Happens When Electrical Engineering Is Incomplete
An incomplete electrical submittal results in a correction request. The correction takes time to resolve: the engineering team must update the drawings, the installer must resubmit, and the AHJ must review again. Depending on the jurisdiction, each correction cycle can add days or weeks to the project schedule.
Repeated corrections on the same project damage the relationship with the AHJ reviewer. Some jurisdictions track submitter records, and installers with high correction rates may face longer review times on future projects.
The fastest path through permitting is a complete, accurate submittal the first time. That requires either an in-house engineering team with deep code knowledge or an experienced engineering partner who understands what each AHJ expects. Learn more about scaling solar installs efficiently, including how outsourced engineering fits into a high-volume operation.
Work with Right Angle Engineering
Right Angle Engineering produces permit-ready electrical plan sets for residential and commercial solar projects in all 50 states. Our electrical engineers are licensed PEs who understand both NEC requirements and local AHJ expectations. We deliver stamped electrical plan sets within 12 hours for most projects.
If your permits are coming back with electrical corrections, or if you want to stop those corrections before they start, contact us through our permit design page. We will review your current workflow and show you where the gaps are.
Frequently Asked Questions
What NEC articles govern solar PV electrical engineering?
The primary governing article is NEC Article 690, which covers photovoltaic systems. NEC Article 705 covers interconnected electrical power production sources. Additional articles apply for wiring methods, conductors, overcurrent protection, and grounding. The applicable code edition depends on which NEC version the local AHJ has adopted.
Does every solar permit require a PE stamp on the electrical plan set?
No. PE stamp requirements vary by state and jurisdiction. Some AHJs require a PE stamp on both structural and electrical documents. Others require it only for systems above a certain size or only on structural documents. Right Angle Engineering tracks PE stamp requirements by jurisdiction and applies stamps where required.
What causes most electrical plan set rejections?
The most common causes are: missing or incorrect wire sizing calculations, rapid shutdown documentation that does not match the installed equipment, grounding schedules that leave components unaccounted for, and inverter specs that do not match the SLD. Many corrections also come from using the wrong NEC edition as the basis for design.
How long does it take to get a PE-stamped electrical plan set?
Right Angle Engineering delivers PE-stamped electrical plan sets within 12 hours for most residential projects. Commercial projects with larger or more complex electrical systems may require additional time. We work with installers on rush timelines when projects have critical permit deadlines.
Can Right Angle Engineering handle multi-state electrical permitting?
Yes. We have licensed PEs in all 50 states and maintain jurisdiction-specific information on AHJ requirements, adopted code editions, and PE stamp rules. For installers working across multiple states, we are able to standardize the plan set format while adapting the electrical documentation to each jurisdiction.
References
National Fire Protection Association. NFPA 70: National Electrical Code, Article 690.
Right Angle Engineering. Solar Plan Sets Explained.
Right Angle Engineering. PE Stamps for Solar: What You Need to Know.
Right Angle Engineering. Permit Drawings vs. Engineering Stamps.