What's A Wet Stamp or PE Stamp?

Before installing a solar system, battery storage, or EV charger, securing permission from the Authority Having Jurisdiction (AHJ) is crucial. However, permitting and interconnection requirements vary widely across the U.S. based on state, county, city, and utility company regulations.

A wet stamp, also known as a professional engineer (PE) stamp, is often required for permitting, yet many installers and homeowners don't fully understand its significance. A PE stamp means a licensed engineer has reviewed and approved the project’s structural or electrical design, ensuring compliance with safety codes and local regulations.

Some municipalities require an electrical permit for solar panel installation, while others mandate a building permit. Local ordinances may modify state building codes due to climate, topography, or geological factors. As a result, solar engineering requirements can differ even between neighboring counties.

Most solar permitting rules are based on the National Electrical Code (NEC) and building codes, but many AHJs demand PE-stamped drawings or additional engineering approvals. This typically requires an electrical, structural, or civil engineer to review project plans and apply their seal, confirming compliance with all regulations. Some jurisdictions accept a letter from a state-licensed engineer instead of a PE stamp, stating that the structure can handle the additional solar system load.

To streamline the permitting process, determine in advance whether your project requires PE-stamped PV drawings, engineering reviews, or approval letters. Being prepared will help you avoid delays and ensure a smoother installation process.

What Is A PE Stamp or Engineering Wet Stamp?

In industries like engineering, architecture, and surveying, official documents often require verification through a PE stamp. In solar and EV charging projects, a PE stamp or wet stamp means that a licensed engineer has certified the design as compliant with all applicable codes and professional standards. This approval is crucial for permitting and liability purposes.

A PE stamp—sometimes mandatory, sometimes optional—serves as an engineer’s registration seal, confirming they take responsibility for the design’s structural and electrical integrity. This can be especially important in areas with strict permitting requirements.

Wet Stamp vs. Digital PE Stamp

A wet stamp is physically applied with ink or embossing on paper plans, along with an ink signature and date.
It includes key details like the engineer’s name, license number, and possibly their affiliated organization.
Many AHJs now accept digital PE stamps, which expedite approvals and reduce paperwork.

Only a certified professional engineer can issue an engineering wet stamp. Earning this certification requires a four-year engineering degree, work experience under a licensed PE, and passing two rigorous exams. Since each state regulates PE qualifications, requirements may vary, making it essential to verify local regulations before submitting stamped drawings.

GreenLancer offers professional solar engineering services, including engineering reviews and PE-stamped drawings, to help streamline the permitting process. With access to licensed engineers across the U.S., we ensure your project meets all AHJ requirements, reducing delays and keeping installations on schedule.

Is a PE Stamp And Wet Stamp The Same Thing?

A PE stamp and a wet stamp are closely related but not identical. While both certify documents, a PE stamp specifically signifies approval from a licensed Professional Engineer. It confirms that an engineer has reviewed and validated the design, ensuring compliance with safety codes and regulatory standards.

In contrast, the wet stamp meaning refers to the physical process of stamping documents, which isn’t exclusive to engineering. A wet stamp is a physical inked or embossed imprint applied by licensed professionals across industries like architecture, surveying, and notarization. Although a PE stamp is a type of wet stamp, not all wet stamps indicate engineering approval.

Both stamps play a crucial role in verifying the legitimacy of professional work. However, a PE stamp uniquely certifies that a licensed engineer is responsible for the design’s integrity, making it essential for many solar, EV charging, and energy storage permitting processes.

Why Are Wet Stamps Or PE Stamps Important?

Securing the correct engineering wet stamp or PE stamp is a crucial step in any solar, EV charging, or energy storage project. A PE stamp means a certified engineer has reviewed the system design, ensuring compliance with safety codes and performance standards. Without this approval, your project could face permitting delays or fail to meet regulatory requirements.

Engineers providing a PE stamp go through rigorous calculations to verify system viability, evaluating structural integrity, electrical safety, and code adherence. If a project lacks the necessary wet stamp, it could lead to major safety risks, operational failures, or even rejection by the Authority Having Jurisdiction. Ensuring proper certification from the start helps prevent costly rework and keeps your installation on track.

How To Get a Solar Engineering Wet Stamp

Some AHJs require a physical wet stamp—either inked or embossed—on paper drawings, while others accept digitally sealed engineer-approved documents. If digital PE stamps are permitted, they can streamline the process, saving time, money, and resources compared to traditional wet stamps.

Steps to Obtain a PE Stamp:

Determine AHJ Requirements
- Check whether your jurisdiction requires a wet stamp or accepts digital PE stamps.
- Verify if the project needs an electrical, structural, or civil engineering review.
Work with a Licensed Professional Engineer
- A PE must review and approve project drawings to issue the required stamp.
- Many solar, battery storage, and EV charging professionals use specialized engineering services.
Plan for Engineering Costs
- Pricing varies based on the number of drawings and project complexity.
- Factor in additional costs if revisions or extra certifications are needed.

GreenLancer provides comprehensive solar engineering services, including permit plan reviews and PE-stamped drawings to meet AHJ requirements. Whether you need electrical, structural, or civil analysis, GreenLancer connects you with licensed engineers who can provide digital stamps or wet stamps for solar, EV charging, and generator projects, ensuring compliance and a smooth permitting process.

Types of PE Stamps for Solar & EV Charging Projects

PE stamps are critical in certifying that installations meet regulatory, safety, and technical standards for solar and EV charging station projects. Here’s a deeper look at the various types of engineering stamps commonly required:

Electrical Engineering Wet Stamps

For solar and EV charging projects, a PE stamp from an electrical engineer is essential to ensure that your system meets all electrical codes and safety standards. Whether it's a new solar installation or an upgrade to existing electrical systems, an electrical engineering wet stamp guarantees that your design has been reviewed and approved by a qualified professional.

What an Electrical PE Stamp Covers

System Design: The electrical engineer checks the design for proper circuit sizing, load calculations, and compliance with the National Electrical Code.
Safety Compliance: The stamp ensures that the system is designed to prevent electrical hazards, including overcurrent protection, grounding, and arc fault protection.
Energy Flow Analysis: The engineer will verify that energy flow is optimized, ensuring efficiency and that the system can handle peak loads without issues.

When You Need an Electrical PE Stamp

New Installations: If your project involves new electrical components, you’ll need an electrical PE stamp to confirm the system’s design complies with local regulations.
Upgrades: For systems that require electrical upgrades (such as increased panel capacity or battery storage), an electrical PE stamp ensures that the new design integrates seamlessly and safely.

Structural Engineering Stamps

A structural engineering stamp is crucial when installing solar panels or EV infrastructure, as it affects the structural integrity of a building or requires ground mounting. Engineers must evaluate the ability of the roof or foundation to support the added weight of solar panels, considering factors such as:

Roof Framing and Load Calculations: Engineers assess how the solar panels’ weight interacts with the building’s existing structure. This includes calculations for vertical loads, such as the panels' weight, and dynamic loads, like wind or snow.
Seismic and Wind Loads: Structural engineers must ensure that the mounting system can withstand these forces in regions prone to earthquakes or high winds, such as coastal or hurricane-prone areas. They may use wind load calculations and seismic reinforcement methods to certify that the installation complies with International Building Code (IBC) standards and local amendments.

Structural engineers must ensure the foundations can support ground-mounted PV systems while accounting for soil composition and maximum wind speeds. In such cases, wet stamps or PE-stamped drawings provide AHJs with certified evidence of the project’s safety.

Civil Engineering Wet Stamps

While less common in residential solar projects, civil engineering stamps are often required for large-scale solar farms or public EV charging stations. Civil engineers focus on the infrastructure surrounding the installation, which can include:

Site Grading and Drainage: Civil engineers may need to ensure proper site preparation, addressing issues like erosion control, drainage systems, and land leveling for solar farms.
Roads, Parking, and Utilities: For EV charging stations, especially those in public or commercial spaces, civil engineers are responsible for designing access roads, parking lot layouts, and utility connections that integrate seamlessly with existing infrastructure. They may also ensure that the installation meets ADA (Americans with Disabilities Act) compliance for accessibility.

Civil engineers may provide wet stamps or PE stamps to verify that the site development complies with local building codes, environmental regulations, and infrastructure standards.

What are the Licensing Requirements for a PE Stamp?

Licensing requirements for obtaining a PE (Professional Engineer) stamp vary by state and jurisdiction. Still, there are some common requirements that most engineers must meet to be eligible to use a PE stamp. Here are some general guidelines regarding PE licensing requirements:

Education: Typically, individuals seeking a PE license must have a bachelor's degree in engineering from an ABET-accredited program or equivalent. Some states may require additional education, such as a master's degree or specific coursework.
Experience: Most states require a certain amount of work experience under the supervision of a licensed Professional Engineer, which can range from 4 to 8 years, depending on the state and the individual's education level.
Examination: To obtain a PE license, engineers usually must pass the Fundamentals of Engineering (FE) and Principles and Practice of Engineering (PE) exams. The PE exam is specific to the engineer's discipline (e.g., civil engineering, mechanical engineering).
Ethics: Engineers are required to adhere to a code of ethics and conduct themselves in a professional and responsible manner.

Licensed professional engineers are typically required to be licensed in the state where they offer engineering services. This ensures that they comply with local regulations, codes, and standards. However, some states have reciprocity agreements that allow engineers licensed in one state to obtain a license in another state without having to take additional exams, provided they meet certain requirements.

Engineers should know the licensing requirements specific to the state or jurisdiction in which they intend to practice. They should contact the state licensing board or regulatory agency for engineering to get detailed information on the specific requirements and processes for obtaining a PE license and using a PE stamp in that state.

When Are PE Stamps Required For Solar Permitting?

PE stamps are often necessary for solar permitting in the following situations:

Structural Modifications: If the solar installation involves structural modifications to a building or structure, such as roof reinforcement or structural supports for ground-mounted systems, a structural engineering stamp may be required to certify the structural design and ensure compliance with building codes.
Electrical Design: For grid-connected solar PV systems, an electrical engineering stamp may be required to certify the electrical design, including wiring diagrams, equipment specifications, and safety considerations, to ensure compliance with electrical codes and regulations.
Professional Oversight: In some jurisdictions, solar installations may require professional oversight by a licensed engineer to ensure compliance with engineering standards and best practices, particularly for large-scale solar farms or complex projects.
Regulatory Requirements: Certain regulatory agencies or local building authorities may require PE stamps as part of the permitting process to verify the safety, integrity, and compliance of the solar installation with applicable codes and regulations.

Consult with local building authorities, engineering professionals, and regulatory agencies to determine whether a PE stamp is required for your specific solar permitting needs and to ensure compliance with relevant regulations and standards.

Engineering Wet Stamps: Critical For Some Solar & EVC Projects

If engineering stamps are needed for a project, they must be provided 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, reviews, and letters 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 solar or EV charging engineering partner and simplify your design and engineering process.