Monthly Archive May 26, 2019

The Reason Why NEMA Electronic Cases Don’t Degrade

During summer in Cleveland, it is a smack dab in the middle of the unimaginable humidity including the sweltering high temperatures and balm nights. If you decided to go and step outside, you will start dripping in unimaginable sweat.  Because of the increase in humid and one can not really tell if they are just sweating or it is just because there is too much liquid collected from the air. One can say that they really hate bitter cold winters, but I will still choose it over any day rather than suffer in heat and humidity.

This is why when it come to electronics enclosure, the NEMA 4 and NEMA 4X rated ones seems to be so cool when it comes to this kind of weather. They are made to endure and withstand the heat because they are designed and engineered using a flame-retardant polycarbonate material. Together with a UL94-HB flame-rating, this enclosure becomes UV stabilized. The impact this material can resist and withstand in terms of temperature ranges from -40 Celsiums to +120 Celsius.

Even of the enclosure cases are not situated or installed in an area that gets water, the present moisture in air can still damage the electronics. The gasket which is provided with the NEMA rated electronics enclosure can help in protecting the internal electronics from that type of moisture. In addition to this, the housings also come with standard and stainless steel enclosure screws.

For the WP NEMA enclosures, WC NEMA and WA series NEMA enclosures – they are all made, designed, and engineered in line with IP65 of IEC 529 and NEMA 1, 2, 4, 4x, 12 and 13 specifications. The electronics enclosure is also listed to have the specifications of UL.508-4x

Some enclosure manufacturing companies can also give NEMA specific mounting boss screws. The 6mm screws can be utilized to effectively secure the PCB unto any of the internal mounting bosses that are carefully molded into the enclosure.

Different Types of Enclosure Seals and Gaskets

Gaskets are necessary enclosure accessory to help seal the electrical enclosures according to the set of standards published by National Electrical Manufacturer’s Association (NEMA). The gaskets can be used from ratings 1 to 12. Some of the most popular ratings for indoor enclosures are 12 and 13. The common enclosures for outdoor application are 3, 4, 4x, 6, and 6P.

The electrical enclosure standards are very crucial because they have direct effect on safety and protection. It can also help the customer choose and obtain the right product for their company or business needs.

With this in mind, the good gasket design in an enclosure is very crucial for the engineer to make a very good seal and it is as important as the gasketing material itself. The design will bring a good impact on the functionality, aesthetics, and the overall performance.

Some of the common gasket types are:

Stripping – these gaskets are being supplied in rolls with a material slit to be able to determine the width that can be cut or separated in length by using the assembler. The low scrap-rate makes the stripping of the gasket cost-efficient. Despite of this, the corner seams of the material roll may make the system more susceptible to wear and leakage. This will only happen if the gasket is not properly designed or even assembled.

Die-cut – Once the material is cut using a steel-rule die, water-jet, or laser, the die cutting process helps in eliminating the corner seams of the material roll. Die-cut gaskets are very popular and common once the complexity of the design does not allow for the stripping or if the overall size of the gasket will not bring in larger center scrap. This can be lessened by designing a “fold-out” gasket.

Form-In Place – when it comes to dispensing the component, an elastomer is applied in liquid form and it is directly applied on the enclosure. The elastomer liquid then forms into a foam and it cures at room temperature. The form in place is usually is cheap to apply and it yields the most benefits once the gasket design becomes very complexed. Or else it will result to an important yield loss without the die-cut shape.Bulb Extrusions – this process can be tailor-fitted or designed specifically for abrasion and/or possible environmental resistance by utilizing very durable and high quality elastomers. The hollow center gives provision and allowance for compressibility as the material can be naturally firm or steady. The skinned surface of the gasket on all sides combined with high density minimizes and decreases any possible water ingress on the enclosure.

Designing Enclosures that can Give Protection Against Water and Object Ingress

In this article, I want to share with you the knowledge that I have in designing and creating enclosures that should be able to withstand some of the extreme, harsh, and worse environmental hazards. This discussion would eventually bring us to the issue between NEMA and IP rating standards. Because these two standards most of the time brings confusion about how they work. With this in mind, this article is meant to somehow clear the air of confusion surrounding this subject. In order to make this more simpler, I will only use NEMA ratings for the majority of specifications but there are IP counterparts for the NEMA ratings I will mention. To make this article relatable.

As the writer of this article, I would like to make it to a point that I emphasized the importance of the designers’ consideration of what they are trying to get in designing enclosure. Design engineers should make sure that their agendas in designing the enclosure should be clear. Are they trying to achieve environmental protection the enclosure can give? Or are they trying to comply with the formal standards and requirement of NEMA for electrical enclosures? The latter might have been greatly influenced by the owner of the company or the manager of operations.

With this in mind, the enclosures should be made sure that these will really deliver what they are designed for. There are several variables a design engineer should consider in choosing the right type of enclosure they should have for their company. There are basic enclosures that give basic protection from any type of solid object ingress. A higher NEMA rating might mean that this enclosure will give higher protection. Unlike the IP ratings, NEMA rating will give the protection it can give aside from the water or solid object ingress.

The main difference between IP and NEMA, the latter gives the level of protection it gives for corrosion protection. For the enclosures that will be installed in very harsh environments, it is important that one of the basic needs for enclosure property is its capability to withstand corrosion. There will be also times that the enclosure will be partly or totally submerged in water so any NEMA rating of 6 will be helpful, so type 6 and 6p are considered as waterproof box, and the weatherproof cabinet is NEMA 4X enclosure.

With this in mind, NEMA enclosures types are primarily set to promote certain standardized product specifications for electrical devices. NEMA is designed to have specifications on how the enclosure should perform given the certain type of environment it will be exposed to. For the harsh environment, it is recommended that type 6 will be used. Aside from these features, NEMA ratings are designed to:

1. Protecting personnel from hazardous internal parts Give protection for personnel that might be exposed to hazardous internal parts and;

2. to protect the enclosure against damage from harsh environmental hazards.