Requirements for waterproof sealing rings at the inlet of lighting electrical ready boards in rural Africa

Based on the climate environment in rural Africa (high temperature, heavy rain, high humidity, and frequent sandstorms), outdoor use scenarios of lighting electrical ready boards, and electrical equipment protection regulations, the following core conclusions are clarified: the box inlet of rural lighting electrical ready boards in Africa must be equipped with waterproof sealing rings, and the material should be selected as the preferred type that is suitable for harsh local environments, has strong weather resistance, and stable sealing performance. The specific requirements are as follows:

1、 The necessity of equipping waterproof sealing rings at the inlet

Lighting electrical ready boards in rural areas of Africa are mostly installed outdoors (although some are easily covered, the protective conditions are poor), and generally face three core environmental challenges, which determine that waterproof sealing rings must be installed at the inlet:

1. Rainproof and moisture-proof requirements: most African villages belong to the tropical savannah and rainforest climate. Rainfall is concentrated and there are many rainstorm. At the same time, the air humidity is high. If the inlet is not sealed, rainwater and moisture will invade the box along the cable gap, resulting in short circuit and corrosion of electrical components. Direct connection will lead to lighting failure and even potential safety hazards of electric shock. This is contrary to the core requirement that outdoor electrical ready boards should meet the protection level of IP54 and above (IEC 60529 standard).

2. Dust and debris prevention requirements: In rural Africa, the weather is sandy and dusty, and there are many insects and small rodents outdoors. The gaps at the inlet are easy to become channels for dust, insects, and small animals to invade. Dust accumulation can lead to poor heat dissipation and poor contact of components, while small animal invasion may cause short circuits in the circuit. The sealing ring can effectively build a physical protective barrier, and with the waterproof gland, the protective effect can be further improved.

3. Adaptation to outdoor protection level: The core protection requirement for outdoor lighting electrical ready boards is dust and water resistance. The inlet, as the weak point between the box and the cable, is a key link in waterproofing and dust prevention. Installing a sealing ring is the basic measure to achieve IP54 and above protection level, which can avoid overall protection failure caused by local sealing loss, extend the service life of the electrical ready board, and reduce operation and maintenance costs.

Additional note: Even if a waterproof gland head is used at the inlet, a sealing ring must be used to achieve double sealing by tightly fitting the sealing ring with the cable and gland head, ensuring reliable sealing. Unused inlet ports also need to be sealed tightly with matching blind plugs and sealing rings to prevent protective loopholes.

2、 Selection of suitable materials for sealing rings (sorted by priority)

Considering the environmental characteristics of high temperature, high humidity, strong ultraviolet radiation, and frequent sandstorms in rural Africa, the sealing ring material should focus on meeting the requirements of high and low temperature resistance, UV aging resistance, waterproof and moisture-proof, good elasticity, easy accessibility, and high cost-effectiveness. The following two materials should be preferred to avoid using ordinary rubber materials with poor weather resistance and easy aging:

1. Priority selection: EPDM sealing ring

EPDM rubber is the optimal material for sealing the inlet of rural lighting electrical ready boards in Africa, with core advantages that fully match the local environment. It is also the mainstream choice for sealing outdoor electrical equipment

Extremely weather resistant: able to withstand temperature fluctuations of -10 ℃~60 ℃ in rural Africa (some high-temperature areas can be adapted to high-temperature resistant models), long-term exposure to strong ultraviolet radiation is not easy to age, crack, or harden, and the service life can reach 5-8 years, greatly reducing the frequency of replacement in the later stage, suitable for outdoor long-term use scenarios.

Excellent waterproof, moisture-proof and sealing performance: with good elasticity and resilience, it can tightly fill the gap between the inlet and the cable or box after compression, without any gaps, effectively blocking rainwater and moisture from entering. At the same time, it has a certain degree of dustproof performance, which is highly compatible with the protection requirements of IP54 and IP65 level electrical ready boards.

High cost-effectiveness and easy accessibility: EPDM rubber has moderate raw material costs, mature production processes, and is easy to purchase in local and surrounding areas of Africa. It is suitable for the low-cost and easy to maintain needs of rural lighting electrical ready boards, and is resistant to chemical corrosion, which can resist slight pollution erosion in rural environments and is not easily affected by environmental factors.

2. Alternative options: Silicone rubber sealing ring

If it is inconvenient to purchase EPDM rubber sealing rings locally, or if the electrical ready board is installed in high-temperature extreme areas (exceeding 60 ℃ for a long time in summer), high humidity low-lying areas, silicone rubber sealing rings can be selected. The core characteristics are as follows:

Wide temperature resistance range: can withstand extreme temperatures of -60 ℃~200 ℃, with better high temperature resistance than EPDM rubber, suitable for use in tropical high temperature areas in Africa. It is not easy to soften or deform in long-term high temperature environments and can maintain stable sealing performance.

Excellent waterproof, moisture-proof and anti-aging performance: the waterproof and sealing performance is equivalent to that of EPDM, with strong UV resistance and ozone aging resistance. It is not easy to mildew in a high humidity environment. It is suitable for rainy and high humidity rural areas in Africa, and has good elasticity. It can adapt to different specifications of inlet and cable outer diameter.

Attention: The cost of silicone rubber sealing rings is slightly higher than that of EPDM rubber, and their resistance to physical tearing is slightly weaker. During installation and operation, it is necessary to avoid scratching with sharp objects; If there is a risk of sand and dust abrasion in the local area, thick silicone rubber sealing rings can be used to enhance durability.

3. Prohibited materials for selection

Ordinary natural rubber, nitrile rubber (NBR) and other materials are prohibited from being used for the inlet of lighting electrical ready boards in rural Africa. These materials have extremely poor resistance to ultraviolet radiation and high temperature, and are prone to rapid aging, cracking, and loss of elasticity after long-term outdoor use. Within 1-2 years, they will lose their sealing function, causing rainwater and sand to invade and cause equipment failure. Moreover, their weather resistance cannot adapt to the complex local environment and do not meet the sealing requirements of outdoor electrical equipment.

3、 Additional precautions

1. Sealing ring specifications: It needs to be accurately matched with the inlet aperture and cable outer diameter to ensure that there is no looseness or gap after compression, and to avoid sealing failure due to non-compliance with specifications; It is recommended to use a sealing ring with a compressibility of 20% -30% to balance sealing effect and service life.

2. Installation requirements: During installation, it is necessary to clean the burrs and dust at the inlet to avoid scratching the sealing ring; The sealing ring needs to be installed in place, tightly attached to the box and cable, and tightened and fixed with a waterproof gland to ensure uniform compression deformation and form an effective sealing barrier.

3. Maintenance replacement: It is recommended to inspect the sealing ring every 3-5 years. If aging, cracking, hardening, deformation, etc. are found, they should be replaced in a timely manner to avoid seal failure; Key inspections are required before the rainy season to ensure reliable protection and reduce the risk of equipment failure.