Explosion-proof is not 'the more expensive the better'
An explosion-proof motor must be chosen for the hazardous area. A higher class than needed wastes money; too low is a safety risk. The key is the gas/dust group and temperature class of the site.
How to read the code
A code like Ex d IIB T4 Gb breaks down as:
| Part | Meaning | Common |
|---|---|---|
| Ex | Explosion-proof mark | - |
| d / e | Protection type | d=flameproof, e=increased safety |
| IIA / IIB / IIC | Gas/dust group | IIC highest |
| T1~T6 | Temperature class | T4/T5 stricter |
| Gb / Db | Equipment category | Gb=high gas protection |
Two common protection types
Flameproof (Ex d): contains potential sparks in an explosion-resistant enclosure, the most common, suits many gas/dust areas.
Increased safety (Ex e): prevents ignition via reinforced insulation and over-temperature protection, suited to motors that do not normally spark. Lighter and often cheaper.
How to set the class
- Pick the type: d or e per the area.
- Pick the gas group: IIA/IIB/IIC per the gas present.
- Pick the temperature class: T group per the ignition temperature.
If unsure, tell the manufacturer the gas type, concentration and temperature, and let them set the class per the standard.
Wangpai explosion-proof range
Wangpai supplies YBX4 three-phase explosion-proof (7.5~355 kW), TBVP PMSM explosion-proof and TBGP HV explosion-proof, covering flameproof / increased safety, customised to the area.
FAQs
Can an explosion-proof motor run in a normal area? Yes, but it is unnecessary and costs more.
Does it need an explosion-proof VFD? If you need speed control, the VFD must also meet the explosion-proof requirement.
How do I confirm my area class? Refer to the hazardous-area classification or ask the manufacturer, based on gas group + temperature class.