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.

Razred in stopnja	Temperatura vžiga in skupina
-	T1	T2	T3	T4	T5	T6
-	T＞450	450≥T＞300	300≥T＞200	200≥T＞135	135≥T＞100	100≥T＞85
I	Metan
IIA	Etan, propan, aceton, fenetil, en, aminobenzen, toluen, benzen, amoniak, ogljikov monoksid, etil acetat, ocetna kislina	Butan, etanol, propilen, butanol, ocetna kislina, butil ester, amil acetat Ocetni anhidrid	Pentan, heksan, heptan, dekan, oktan, bencin, vodikov sulfid, cikloheksan, bencin, kerozin, dizel, nafta	Eter, acetaldehid, trimetilamin		Etilnitrit
IIB	Propilen, acetilen, ciklopropan, koksarniški plin	Epoksidni Z-alkan, epoksidni propan, butadien, etilen	Dimetil eter, izopren, vodikov sulfid	Dietileter, dibutil eter
IIC	Vodni plin, vodik	Acetilen			ogljikov disulfid	Etil nitrat

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.

V smislu temperatura 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.