Junction Box Potting

[Hilma Klingaman]

TheRPC-2114 Series Potting Compound is a re-enterable, electrical insulating and potting compound. It is designed for use in RJB-Series junction boxes as required by NEC 680. Its tacky urethane formulation adheres well and pulls away cleanly for fast splice re-entry. It is non-corrosive to copper and brass.

Note: Article 680-52(b) of the National Electric Code (N.E.C) requires that all underwater junction boxes and all underwater enclosures be filled with an approved potting compound to prevent entry of moisture.

Junction boxes are installed on the backside of photovoltaic (PV) panels and serve to protect electric components from environmental elements. To improve junction box mounting and protect integral components, a solar panel manufacturer was exploring ways to decrease costs, improve manufacturing efficiency, and meet panel lifetime expectations.

The customer was looking for the most efficient and consistent way to pot their solar panel junction boxes. It was paramount that they found a reliable solution that would protect the ribbon wire connection from corrosion as well as protect against moisture ingress through the back panel. In addition, the potting materials had to seal and adhere to a variety of substrates including a plastic junction box, metal ribbon wires, and the glass back panel.

Graco and its distributor partner worked to provide a meter, mix, and dispense system to process a 20:1 (by volume) silicone potting material with a shot size of approximately 30 cc. To verify the application, Graco qualified its PR70 Posi-Ratio Meter, Mix and Dispense System at the Graco application lab in North Canton, Ohio. The 20:1 volumetric ratio was easily obtainable with the PR70v variable-ratio system. Ratio and shot size repeatability studies proved the system to be reliable in processing the potting material. An additional benefit of the PR70v Variable Ratio system is that the dispensing ratio can be fine-tuned without additional hardware or kits. If the ratio of the material needs to slightly change, the PR70v machine can handle it.

The PR70v was equipped with an MD2 Dispense Valve with a spring-loaded poppet nose to keep the base material separate from the catalyst material within the MD2 valve. Since the catalyst material is moisture sensitive, the catalyst tank was equipped with the nitrogen blanket accessory to displace moist air. Both the base and catalyst tanks were equipped with a low-level sensor to indicate when a refill is required. Additionally, the base tank was equipped with an automatic refill-kit for automatic refilling of the tank using a drum supply system.

Material ratio, flow rate, and shot size consistency were all critical factors when potting junction boxes. The Graco PR70v was able to perform exceptionally on all three requirements. With the level sensors and Base side auto-refill, the system had the overarching capabilities to meet their goal of high volume solar panel production. With the PR70v Posi-Ratio Meter, Mix, and Dispense System, the customer is well equipped to reliably and repeatedly dispense the potting material into the solar panel junction boxes in a mass production manufacturing environment.

Reenterable two-component silicone gel for insulated filling and sealing of casings and junction boxes housing electrical components and connections of up to 1 kV or electronic components. Waterproof, Dust Protection, Electrical Insulation, Critter Proofing

MPgel plus is a reenterable two-component silicone gel for insulated filling and sealing of casings and junction boxes housing electrical components and connections of up to 1 kV or electronic components, suitable for a wide range of applications and industries.

From solar panel adhesives and bonding compounds to electrical component encapsulation materials, Epic Resins is a leading supplier of resins formulated to withstand the intense environmental conditions common to solar energy system components. Thorough testing and innovative formulations keep us on the leading edge of resin production for the solar industry.

Epic Resins is an integral supplier of resins to diverse solar and alternative energy markets worldwide. We have over 50 years of technical, manufacturing and service experience in products and processes that are vital to the solar energy device market.

When it comes to J-Box encapsulation materials, Epic Resins understands the importance of providing a low cost, proven solution. Epic Resins materials withstand all the outdoor elements solar technology is exposed to. Epic Resins polyurethane and epoxy resin encapsulating compounds keep your products protected from moisture and demonstrate great hydrolytic stability in many different temperature environments.

Our materials are dedicated to keeping the solder joints in the J-box protected. Epic Resins epoxies and polyurethanes adhere to J-Box case materials better than traditional, expensive silicones. With a wide variety of characteristics, our resin potting compounds will protect sensitive electronics and PCBs in a wide range of systems and environments.

Epic S7142-01 is a two-component polyurethane potting compound designed for the manufacture of ballast transformers. S7142-01 is recognized by UL as a 94 V-0 product in thicknesses as thin as 2.9mm. S7142-01 has also been designed for good thermal shock and hydrolytic stability and has the option of being cured at ambient or elevated temperatures to facilitate high volume/speed production.

Epic S7253 is a series of two-component products, UL 94V-0 recognized polyurethane compounds designed for electronic applications requiring encapsulation. The low weight loss of the S7253 series at elevated temperature suggests that this product is suitable for applications that can reach up to 125C. The S7253 series is currently utilized in a variety of applications, including automotive applications that require thermal cycling between -40C and 105C. The S7253 series of products feature good thermal conductivity along with good adhesion to various metals and plastics. The S7253 series of products meet RoHS requirements and can be adjusted to fit the speed of your production lines.

Epic Resins is an industry-leading manufacturer of custom potting compound formulations, allowing us to serve a wide range of industries and clients. We are fully capable of adjusting existing formulas or starting from the ground up, creating custom compounds for your specific product needs. Our thorough testing process and efficient production systems enable us to keep short lead times without sacrificing product quality. Between our extensive potting compound line and our flexible formulation process, you're sure to get the exact product you need.

Guangzhou Baiyun Chemical Industry Co., Ltd. was established in 1985, which is the first silicone sealant research and production company in China. During this 36 years history, we always provide excellent silicone sealant solutions and service to our customers.

This product is a two-component condensation type silicone potting compound which cures at room temperature. It has the characteristics of fast curing speed, easy flow potting, yellowing resistance, water and moisture resistance, excellent insulation performance, and wide bonding substrate. The product is suitable for pouring and potting of large-area bonded seals such as photovoltaic junction boxes, integrated circuit boards, transformers, and waterproof power supplies.

Sealant products are not toxic after they are fully cured, but should avoid contact with eyes before curing. If contact with eyes, rinse with plenty of water and consult a doctor.uncured products should be kept out of contact with children. The product will release small molecular substances during the curing process, and ventilation should be paid attention to in the construction and curing areas to prevent the concentration of small molecular substances from being too bad for people.

Attention: The data and information presented in this catalog may not be relied upon to represent standard values. We reserves the right to change such data and information. However, because conditions and methods of use of our products are beyond our control, so we cannot ensure the validity and applicability of some usage, before using the product, users should read the technical data carefully, then decide the best way to use sealant.

I need some small/cheap waterproof junction boxes for some 12v garden lighting. I am considering using little (25mm x 25mm x 15mm) potting boxes and after soldering the wires, then filling the potting box with hot melt glue.

If you are just protecting some spliced wires, then hot glue may work if you do a good job. The worst situation is if the junction box is completely filled with water. If you do a complete job around each splice, then you might succeed. If there are holes, however, water will get in and be trapped.

If there is a PCB in there, then be careful. A hard and rigid potting compound will expand and contract with temperature, and often the thermal coefficients between the compound and the PCBA are different. The result is parts being snapped off the PCB.

The softest potting compound for a PCB is silicone. It is gentle on the components and does very well at temperature extremes. However, silicone doesn't adhere very well and will pull away from the surfaces it is stuck to, which will invite water ingress.

I have used direct-burial low-voltage splice kits consisting of a plastic tube filled with some kind of grease. They were closed on one end like a chemistry test tube. The other end had some kind of snap closure that held the wires from pulling out. I saw an ad for one brand that advertised that silicone grease was the filling. These should be available where outdoor lighting or automatic lawn watering components are sold. The wire connection was done with a twist-on connector that fit into the tube. The grease remains soft.

3a8082e126