Solar installations are sold on 25-year performance warranties, but the components that actually determine whether an array survives that long rarely get the attention they deserve. Racking systems, junction boxes, inverters, and panel frames all depend on solar panel array seals to keep out moisture, dust, and UV degradation across decades of continuous outdoor exposure. When these seals fail – and with the wrong material, they eventually do – the consequences range from reduced energy output to complete panel failure and costly field replacements.
This article looks at what solar panel array seals actually do, why material selection matters so much in this application, and what to look for when specifying or sourcing sealing components for solar hardware.
What Do Solar Panel Array Seals Actually Protect?
A solar array isn’t a single sealed unit – it’s an assembly of components, each with its own sealing requirements:
Junction Box Seals The junction box on the back of every solar panel houses the electrical connections between cell strings and the external wiring. This is one of the most critical sealing points in the entire system, since water intrusion here can cause short circuits, corrosion, and complete panel failure.
Frame and Edge Seals Panel frames are sealed against the glass and backsheet to prevent moisture from migrating into the laminate itself, which can cause delamination and reduce cell efficiency over time.
Racking and Mounting Seals Where panels attach to racking systems, gaskets prevent water pooling and galvanic corrosion between dissimilar metals, while also absorbing vibration from wind loading.
Enclosure Seals Inverters, combiner boxes, and other electrical enclosures rely on gasket seals to maintain their weatherproof rating (typically NEMA or IP-rated), keeping moisture and dust away from sensitive electronics.
Cable Entry Seals Wherever cables pass through an enclosure or panel housing, a seal is needed to maintain the weatherproof rating at that penetration point.
Each of these locations experiences a different combination of stress – some see constant UV exposure, others see thermal cycling between hot daytime and cold nighttime temperatures, and enclosure seals need to maintain compression over years without being serviced.
Why Material Selection Matters So Much for Solar Applications
Solar installations present a uniquely demanding sealing environment, which is exactly why material choice has such an outsized impact on system reliability.
Extreme UV Exposure Solar panels are, by design, mounted in locations that receive maximum sun exposure – which means any exposed sealing material takes the full brunt of UV radiation, day after day, for the life of the system. Materials without strong UV resistance crack, chalk, and lose sealing force within just a few years.
Wide Temperature Swings Rooftop and ground-mount solar arrays can swing from below-freezing overnight temperatures to well over 150°F on the panel surface during peak summer sun. Seals need to maintain flexibility and compression across that entire range without becoming brittle in the cold or losing their shape in the heat.
Decades-Long Service Life Expectations Unlike many industrial applications where a seal might be serviced or replaced periodically, solar arrays are often installed once and expected to perform with minimal maintenance for 20-25 years. That means the sealing material needs to resist compression set – the tendency of a seal to lose its shape and sealing force after prolonged compression – far longer than in most other applications.
Electrical Safety Requirements Because solar panel array seals often sit adjacent to live electrical connections, flame retardancy and dielectric properties matter. Enclosure gaskets in particular often need to meet UL flammability ratings to satisfy electrical code and product safety certification requirements.
Weather and Moisture Ingress Protection Beyond rain, solar installations need to handle condensation, humidity cycling, and in coastal installations, salt air exposure – all of which can degrade lower-quality sealing materials faster than inland, drier environments.
Why Thermoplastic Elastomer Seals Fit Solar Applications So Well
Given these demands, thermoplastic elastomer (TPE) and thermoplastic vulcanizate (TPV) materials – particularly Santoprene™ – have become a preferred choice for solar panel array seals over traditional rubber compounds, for several reasons:
Superior UV and Ozone Resistance TPV materials are engineered to resist UV degradation significantly better than standard EPDM rubber, which matters enormously given how much direct sun exposure solar hardware receives.
Consistent Compression Set Performance Since solar seals often can’t be inspected or replaced without significant labor cost (especially on large ground-mount or rooftop arrays), material that holds its compression set over many years reduces the risk of seal failure going unnoticed until it causes a system fault.
Flame Retardant Grades Available For enclosure and junction box applications near electrical components, UL 94 flame-retardant TPV grades help installations meet electrical safety code requirements.
Wide Operating Temperature Range Quality TPV compounds maintain flexibility across a broad temperature range, from sub-freezing conditions to the elevated surface temperatures panels reach under direct sun.
Manufacturing Precision Because TPV seals are produced through extrusion or molding with tight process control, gasket dimensions stay consistent across large production runs important for solar manufacturers producing thousands of identical panel or enclosure units.
Common Profile Shapes Used in Solar Sealing Applications
- Junction box gaskets– typically custom-molded or extruded to match the specific box geometry and maintain an IP65 or higher weatherproof rating
- Frame edge seals – U-channel or custom profiles that wrap the panel edge between glass, frame, and backsheet
- Enclosure door gaskets – compression seals for inverter housings and combiner boxes
- Cable gland seals – grommet-style seals maintaining weatherproofing at cable entry points
- Racking interface gaskets – flat or custom gaskets preventing metal-on-metal contact and moisture retention at mounting points
How SantopSeal Supports Solar Panel Array Seal Applications
SantopSeal Corporation, based in the USA, manufactures custom extruded and molded seals made from Santoprene™ TPE/TPV compounds – material well suited to the UV exposure, temperature extremes, and long service-life demands of solar hardware. The company’s Energy & Power Generation industry experience covers seals for both solar and wind equipment housings, where weatherproofing and long-term durability are non-negotiable requirements.
For solar manufacturers and installers evaluating sealing components, SantopSeal’s process includes:
- Reviewing the specific sealing location (junction box, enclosure, frame, or cable entry) and its exposure profile
- Recommending an appropriate Santoprene™ TPV grade, including UV-stabilized and flame-retardant options where needed
- Producing custom profiles or molded gaskets matched to exact panel, box, or enclosure geometry
- Manufacturing to ISO 9001-certified quality standards for consistent, repeatable dimensional accuracy across high-volume production runs
Because solar hardware manufacturers often need consistent gasket quality across large production volumes with minimal field failures, working with a manufacturer that controls material sourcing, die design, and quality control in-house reduces the risk of variability that can lead to premature seal failure in the field.
Getting the Sealing Spec Right From the Start
Solar panel array seals rarely fail all at once – they degrade gradually, often going unnoticed until moisture intrusion causes an electrical fault or a measurable drop in panel output. Given the 20-25 year service expectations built into most solar warranties, getting the sealing material and design right at the manufacturing stage is far more cost-effective than dealing with field failures years into an installation’s life.
SantopSeal Corporation works with solar hardware manufacturers and engineering teams to specify and produce sealing components engineered for the UV exposure, temperature extremes, and long-term durability that solar applications demand. To discuss a solar panel array seal application or request a quote, visit santopseal.com or call +1 (412) 444-1888 or email info@santopseal.com to discuss with their engineering team directly.
