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How a NEMA 4 Breather Drain Protects LED Signs From Harsh Conditions

May 12, 2022

How a NEMA 4 Breather Drain Protects LED Signs From Harsh Conditions Image

Outdoor LED signs are one of the best ways to capture the attention of a passerby and provide them with directional guidance. However, sometimes Mother Nature can be pretty extreme and finicky; in some parts of the country, it’s not uncommon to have record high temperatures followed by snowy conditions in 24 hours. These extreme weather conditions can be detrimental to the functionality and lifespan of LED signs. Fortunately, modern engineering has solutions, such as a NEMA 4 breather drain, that can help combat the harmful effects of the elements on electronic components. Let’s explore some of the elements and factors that affect LED signs, their detrimental effects, and how installing this specialized drain helps to maximize an outdoor sign’s value.



Moisture — rain, snow, snowmelt, and humidity — is a mortal enemy of any electronic device. This holds especially true for electronic components tightly packed within a framed cabinet, like an LED sign. Excessive rain, snow, and humidity can leak into the sign’s cabinet and nearly instantaneously destroy its electronics. To combat this, silicones and other waterproof substances are often used to create a barrier that seals off the sign from rain, snow, and humidity. However, these sealants can present additional problems (more on that later). Additionally, outdoor conditions can cause these sealants to break down, leaving the sign’s electronics exposed to moisture. If the sign doesn’t immediately fail from an onslaught of water, the buildup of moisture over time can lead to corrosion and rusting, inevitably leading to sign failure.


Much like water, dust also poses a big problem for electronic components. Dust contains tiny particles of both moisture and oil that can short out electronics if left unchecked over time. Dust also has small amounts of minerals and other carbon-based contaminants. These can conduct electricity and prevent the conduction of electricity, i.e., make the electronics of the sign not function correctly. Over time, this can cause irreversible damage to electronics and their electromechanical components, elevate electricity costs, and shorten the lifespan of the LED sign.

Temperature Swings and Varying Air Pressure in a Sealed Cabinet

Typically, extreme temperatures don’t negatively affect LED signage. Modern LED signs are manufactured with components that will operate flawlessly in extreme heat (up to 165°F) and extreme cold (down to -40°F). However, there are environments where temperatures climb or fall outside of this range. When these extreme conditions are expected, special provisions, such as small heaters in the sign’s cabinet, ensure the sign’s functionality and longevity.

When LED signs are installed in environments susceptible to extreme temperature swings, problems can occur. As previously mentioned, LED sign cabinets can be sealed with silicones and other waterproof substances to repel dust and moisture. This seal can create a vacuum, not unlike the tires on a car. Air is a gas, and it expands when heated and contracts when cooled. In terms of tire pressure, as a rule of thumb, for every 10°F change in air temperature, tire pressures will change about 2 percent (increase with hot air, decrease with cool air). This principle applies to LED sign cabinets sealed with waterproof barriers, except with a sign cabinet, the consequences are much more dire than over/underinflated tires. Varying pressures within a sign can lead to it collapsing or expanding, damaging the sign's face and electronic components within it.

As previously mentioned, sealants used to safeguard signs from moisture and dust can break down over time. This can also present problems for signs installed in environments susceptible to air pressure swings. If water — rain, snowmelt, condensation, etc. — collects on the exterior of a sign, it can be sucked into the sign cabinet from a drop in air pressure. Without anywhere to go, all that water sucked into the sign can catastrophically damage it.

The Solution: The NEMA 4 Breather Drain


Obviously, moisture, dust, and massive changes in air pressure are the mortal enemies of LED signs, their cabinets, and their electronic components. The NEMA 4 breather drain is an excellent option to protect LED signs from these adverse conditions without using sealants while prolonging the sign’s functionality and useful life. It effectively drains moisture inside the LED sign cabinet while allowing airflow so the sign can breathe with the surrounding atmosphere. Further, it has an internal dust seal that traps dust and can easily be cleaned with compressed air. By keeping the sign breathable and free of moisture and debris, the NEMA 4 breather drain is the best component to maintain the functionality and prolong the life of outdoor LED signage.

Are you looking to install outdoor LED signage in a challenging environment? Our team of engineers and our knowledgeable sales staff are ready to help you find the solution to meet your needs. As the leading manufacturer of LED signage systems and turnkey solutions for outdoor applications, we’re ready to provide you with LED signage solutions that endure the harshest conditions. Contact us today to learn more!