EX D OR EX E: WHICH IS SUITABLE FOR YOU?
"Which protection method is suitable for our business?" is one of the most frequent queries we get from customers. And that is a legitimate query. In order to ensure the safety of your employees, your explosion-proof enclosure must be suitable with the environment in which it is being installed.
However, how can you choose the enclosure that is best for your organisation when there are so many protection techniques available, each of which is customised to a distinct hazardous environment? In this post, we'll compare two popular protection strategies (Ex d and Ex e) so you can decide which enclosure is best for your company.
Ex d and Ex e enclosures: what are they?
Let's start by defining what explosion-proof enclosures include. It is simple to presume that this protective equipment is resistant to external explosions based on the naming practise. This is untrue, though. The capacity of the equipment to contain any internal explosion or spark that occurs inside the enclosure is referred to as being "explosion-proof".
Explosion-proof enclosures are created to contain any explosion or spark that originates inside the enclosure in order to safeguard the surrounding environment. To prevent the fire from escaping the cage, the equipment must be able to withstand extremely high temperatures. These enclosures therefore act as a safety precaution by keeping any spark produced by faulty machinery from escaping and igniting any nearby combustible materials in the potentially dangerous environment.
Let's examine the two most popular forms of explosion-proof enclosures, as defined by the IEC (International Electrotechnical Commission) standard, namely Ex d and Ex e enclosures, now that we have defined what an explosion-proof enclosure is.
Ex d enclosures are made to securely confine both an explosion and the pressure it creates. They stop fire or sparks from erupting from the cage and into the explosive space. Containment is prioritised above prevention.
Ex e enclosures are created with a focus on greater safety. As a result, these enclosures need to be able to endure high internal and exterior temperatures as well as sparks. Additionally, they are made to run cool, which eliminates the possibility of arcs, sparks, and hotspots. Ex e enclosures, in contrast to Ex d enclosures, emphasise prevention above confinement.
Ex d and Ex e enclosure setup and maintenance
To contain an explosion and the pressure that goes along with it, an explosion-proof enclosure has to be thicker. Ex d enclosures are often larger, thicker, and heavier than Ex e enclosures as a result. Ex e enclosures are simpler to install and maintain since they are lower in weight and have a more compact design.
Ex e enclosures also don't have any flame routes, which makes maintenance considerably simpler. Ex d enclosures must have flame pathways in their designs since they are designed to confine an explosion. These flame trails are essential for putting out fires before they may spread to the surrounding area.
The difficulty in maintaining an Ex d enclosure lies in the quantity of bolts (needed to maintain an appropriate flame gap) that must be tightened to a specified tension. To access the internal components for maintenance operations, a technician must remove these bolts in the proper order. The procedure becomes more difficult and time-consuming as a result. The technician must make sure the proper flame gap is preserved when putting the housing back together once the repair is finished. The Ex certification will be void if this isn't done.
Additionally, it could be difficult to locate Ex d enclosures that are approved for IIC gas groups. Ex d enclosures made for locations where gases in the IIC gas group are present must have narrower flame gaps because they are considered to pose a substantial danger. Consequently, it takes more work to produce them. Since fewer Ex d enclosures are available for IIC applications, the ones that are generally more costly and difficult to maintain. Ex e enclosures do not have this problem because they do not have flame routes.
The majority of Ex d enclosures are not appropriate for installation in conditions below -20° C, which is one last point to be made. This is due to changes in a gas or vapour's properties at low temperatures. On the other hand, Ex e enclosures are likely to have a significantly wider temperature rating since they are made to stop an ignition source from happening. They are therefore more adapted to cold climates.
We really hope that the information we have provided has helped you decide which explosion-proof enclosure is best for your company. No matter what choice you make, when installing the explosion-proof enclosure, you should pay attention to its maximum voltage.
For instance, at Supermec, the maximum voltage for our Ex d and Ex e junction boxes is 1000V. They are therefore inappropriate for any transformer with a voltage rating higher than 1000V. The operations of your company and the safety of your employees might be put in danger if you don't follow the safety regulations. The product specifications of your explosion-proof equipment must thus always be carefully read.
Contact our helpful sales staff at bwzm18@ledbenweilighting.com or give us a call at +86 18588981645 if you need help deciding whether explosion-proof electrical equipment is best for your company. We'd be happy to tell you more about our explosion-proof products.
