Which Explosion-Proof Level Is Higher, BT4 or CT6

The BT4 model is classified under Explosion-proof Class B with a temperature rating of T4, stipulating that the equipment’s surface temperature cannot exceed 135°C.

Class And Level	Ignition Temperature And Group
-	T1	T2	T3	T4	T5	T6
-	T＞450	450≥T＞300	300≥T＞200	200≥T＞135	135≥T＞100	100≥T＞85
I	Methane
IIA	Ethane, Propane, Acetone, Phenethyl, Ene, Aminobenzene, Toluene, Benzene, Ammonia, Carbon Monoxide, Ethyl Acetate, Acetic Acid	Butane, Ethanol, Propylene, Butanol, Acetic Acid, Butyl Ester, Amyl Acetate Acetic Anhydride	Pentane, Hexane, Heptane, Decane, Octane, Gasoline, Hydrogen Sulfide, Cyclohexane, Gasoline, Kerosene, Diesel, Petroleum	Ether, Acetaldehyde, Trimethylamine		Ethyl Nitrite
IIB	Propylene, Acetylene, Cyclopropane, Coke Oven Gas	Epoxy Z-Alkane, Epoxy Propane, Butadiene, Ethylene	Dimethyl Ether, Isoprene, Hydrogen Sulfide	Diethylether, Dibutyl Ether
IIC	Water Gas, Hydrogen	Acetylene			Carbon Disulfide	Ethyl Nitrate

Conversely, the CT6 model holds a Class C explosion-proof rating, covering the requirements of BT4 and applicable to zones with dangerous gases like hydrogen and acetylene. T6 equipment must maintain a surface temperature no higher than 85°C.

In terms of temperature categories, T6 represents the highest safety level, suggesting that a lower equipment surface temperature is preferable.

As a result, CT6 possesses a superior explosion-proof classification.