7 Joo Koon Crescent Singapore 629024
Stay connected:
Understanding The Various Classifications Of Ex-Proof Motors

Understanding The Various Classifications Of Ex-Proof Motors

When it comes to operating in hazardous locations, using explosion-proof (ex-proof) electric motors is often recommended for the safety of the equipment and people. Ex-proof motors are designed to be used in dangerous environments with flammable gases, fibres, or dust.

Electric motors produce heat under normal operating conditions and can generate a spark in case of a motor coil failure. As such, it is essential for electric motors, even explosion-proof ones, to be chosen, installed, and set up correctly.

If you want to purchase an ex-proof electric motor, you should consider the motor’s class, division, and group. To understand more about them, here is everything you need to know about the classes, divisions, and groups of ex-proof electric motors.

Classes of Ex-Proof Motors

Ex-proof electric motors are divided into three classes. Class I motors are those that can be placed in an environment where there are explosive vapours. The apt locations for these motors may contain gases and vapours that can auto-ignite and cause explosions like acetylene and gasoline.

On the other hand, Class II motors are utilised in areas where there are vast amounts of dust that is electrically conductive. The suitable locations for these motors may involve the presence of flammable dust, such as coal and grain. Flammable fibres like textiles may be present in the locations of these motors. Lastly, Class III motors keep dust away and ensure that the motor temperature does not increase enough to result in an explosion. 

Divisions of Ex-Proof Motors

The appropriate locations of ex-proof motors are further categorised into two divisions. Division I locations are hazardous even in ordinary conditions. Here, flammable liquids or matter are generated, and they gather as a consequence of the conduct of manufacturing processes.

On the other hand, division II locations are those that become hazardous in abnormal conditions. Areas are usually considered a property belonging to division II when a burst, rupture, or leak resulting in seepage or spillage of flammable substances is present therein.

Groups of Flammable Agents

Aside from their locations, ex-proof motors are broken down into groups based on the principal flammable agents present in their environments. For groups A to D, the gases and vapours that may be present in an ex-proof motor’s environment include acetylene, acetone, ethylene, and hydrogen. On the other hand, groups E to G pertain only to flammable particulate matter and cover aluminium, corn, coal, and sugar.


Understanding and selecting the proper ex-proof motor classification is necessary because it can prevent explosions and save lives. Furthermore, by choosing the right ex-proof motor, you can also enhance the productivity of your personnel and the efficiency of your business operations while maintaining the appropriate levels of safety.

By having a profound understanding of the various classes, divisions, and flammable components involved in the applications of industrial electric motors, you can operate your facility in the safest way possible and avoid the need for frequent ex-proof motor overhauls or electric motor rewinds.

However, should your electric motor require overhauling, rewinding, or repair, seeking the assistance of companies that specialise in mechanical and electrical engineering in Singapore is highly advised. They typically have the expertise necessary to fix and maintain different types of electric motors, whether ex-proof or not. Their services are what your electric motor needs to last long.