Shenhai Explosion-Proof
Explosion-proof electrical equipment is categorized into six types based on their maximum surface temperatures: T1, T2, T3, T4, T5, and T6. These categories align with the ignition temperature groups for combustible gases.
| Temperature level IEC/EN/GB 3836 | The highest surface temperature of the equipment T [℃] | Lgnition temperature of combustible substances [℃] |
|---|---|---|
| T1 | 450 | T＞450 |
| T2 | 300 | 450≥T＞300 |
| T3 | 200 | 300≥T＞200 |
| T4 | 135 | 200≥T＞135 |
| T5 | 100 | 135≥T＞100 |
| T6 | 85 | 100≥T＞8 |
The term ‘maximum surface temperature’ denotes the highest temperature that can be reached on the surface or parts of the explosion-proof electrical equipment under both normal and the most adverse conditions deemed acceptable, with the potential to ignite surrounding explosive gas mixtures.
The guiding principle for temperature classification in explosion-proof electrical devices is as follows:
The peak surface temperature generated by the device must not be capable of igniting adjacent combustible gases, and it should not exceed the ignition temperature of these gases. For safety ratings, T6 devices rank the highest, while T1 devices are at the lower end.
This demonstrates that for explosive materials with identical temperatures, it reflects the lower boundary of their ignition temperatures. Conversely, for explosion-proof electrical equipment, it denotes the upper limit of their maximum surface temperatures, showcasing a clear distinction in characteristics.
Given that explosion-proof electrical equipment utilized in explosive dust environments clearly states the device’s maximum surface temperature, the “Electrical Equipment Design Code for Explosive Hazard Environments” no longer divides explosion-proof electrical equipment into temperature groups.