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  • Sarah Lozanova

What Are Engineering Wet Stamps And Why Are They Important For Solar Installations?


Before installing a solar system, battery storage, or EV charger, it is critical to get the necessary permission from the Authority Having Jurisdiction (AHJ). However, permitting and interconnection requirements vary widely across the United States, depending on state, county, city or municipality, and utility company.


For example, some municipalities require an electrical permit to install solar panels, while others require a building permit. Likewise, some counties and cities may have local ordinances that amend state building codes due to climatic, topographic, or geologic factors. Therefore, permitting requirements vary across states and even counties within the same state.


Solar and EV permitting requirements are based partially on National Electrical Code (NEC) and building codes. However, some AHJs require professional engineer (PE)-stamped drawings during the permitting process.


This requires working with an electrical, structural, or civil engineer to review the project plans and provide their digital seal. It involves a third party with extensive engineering knowledge to check site plans and solar designs.


However, cities might not require PE stamps for all projects. In some cases, a letter from a state-licensed engineer stating the building can handle the additional load of a solar system is required.


Before starting the solar permitting process, it’s essential to get organized and determine if PE stamped drawings or letters are required.


What Is An Engineering Wet Stamp?

Many industries have standards they need to follow. A PE wet stamp certifies that a solar power installation, EV charger, or energy storage project has been designed to applicable codes and professional standards.


It means that a PE has offered their “registration seal” on the drawings showing that it is an engineer-certified plan. It shifts liability because it shows that an engineer is responsible for the plan’s integrity. Sometimes, PE stamps are required, whereas other times, they are optional.


A wet stamp is applied via ink or embossing on paper plans and includes an ink signature and date. However, many AHJs allow digital engineering stamps. When possible, using digital stamps on drawings instead of wet stamps helps expedite the process, saving time, money, and paper.


A certified PE can provide an engineering wet stamp. Certification requires a 4-year degree, working under another PE, and passing two exams. Each state regulates the given PE qualifications.


Different Types Of Wet Stamps

Various AHJs have different requirements for engineer-stamped drawings.


Often, the requirements vary depending on the climate or if the area is prone to natural disasters. For example, wind loads might be a top concern in some climates due to hurricanes. In other locations, seismic activity might be a big consideration.


Let’s look at the different types of wet stamps you may encounter.


Electrical Wet Stamp

When an electrical engineer approves electrical designs involving solar modules, they will look at wire sizing, interconnection method, and other electrical aspects of a project. Therefore, it is critical that the electrical infrastructure can handle the load from solar projects in order to be certified.


Structural Wet Stamp

There are various forces at play on homes, buildings, and ground mounts, including vertical loads, horizontal loads, and longitudinal loads. The structural analysis examines the forces of these loads on structures and other elements, including snow, seismic, dead, imposed, and wind loads. This process also entails looking at the roofing material, the type of roof framing, the weight of the PV modules, site-specific structural calculations, and the structural design of a racking system.


Obtaining a structural wet stamp requires a structural engineer to review the drawings, taking into account these various loads and the code and safety requirements of the AHJ. For example, it might include reviewing wind load calculations and solar panel racking system details. For pole mounts, it might require specifying information about the foundation, considering the soil composition and maximum wind loads.


Civil Wet-Stamp

Civil engineers work on infrastructure, relating to roads, bridges, airports, and other projects. Although civil engineer-approved drawings are somewhat rare for residential to smaller-scale solar projects, they are more common with larger commercial and utility-scale solar installations. Likewise, EV chargers in public parking lots may require civil engineer-stamped drawings.


How To Acquire Solar Engineering Wet Stamps

Some AHJs require ink or embossed stamp on paper drawings. This involves using paper drawings for a project.


However, if an AHJ merely requires engineer-approved drawings, it’s often possible for the engineer to sign off on digital copies. Using digital sealing can save time, paper, and money over wet stamps when feasible.


To obtain wet stamps or digital engineer seals requires working with a PE. Solar, battery storage, and EV professionals often use a professional service to meet this requirement. Pricing varies for this service and usually depends on how many drawings require PE stamps.


GreenLancer offers PE review services, including reviewing permit plan sets and applying a PE seal for an AHJ. In addition, GreenLancer offers electrical, structural, and civil analysis, digital stamps, and wet stamps from licensed professional engineers.


Engineering Wet Stamps: A Vital Part For Some Solar Projects

If PE engineering stamps are needed for a project, it’s essential to provide them to obtain project permits and prevent delays. Because most solar energy, battery storage, and EV professionals don’t typically have these capabilities in-house, partnering with an engineering firm that offers electrical, structural, and civil engineering seals is critical.


GreenLancer has a network of certified engineers with expertise in every AHJ in the country and beyond. Sign up for free today to find your next engineering partner and simplify your solar design and engineering process.