What is the difference between these two explosion protection ratings? Is there a big difference in price?
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This post was last edited by zb030121eric on 2022-12-9 11:00. What is the difference between the explosion protection ratings of ExdmbⅡCT4 and EXdⅡBT4? Is there a big difference in price? The solenoid valve was originally designated as EXdⅡBT4, but the manufacturer suggested changing it to ExdmbⅡCT4. Could this be a trick?
All are flameproof; changing from IIB to IIC represents an upgrade, while mb refers to potting. There should be no problem
EXdmbⅡCT4 refers to encapsulated flameproof type, while EXdⅡBT4 is flameproof type; the flameproof type offers a higher safety level than the encapsulated flameproof type. Moreover, category ⅡC has a higher safety level than category ⅡB. Therefore, in practical applications, the encapsulated flameproof type of category C is often used as a substitute for the flameproof type of category B
1. The explosion-proof type of electrical equipment installed in different hazardous areas shall meet the following requirements: Zone 0: ia, S； Zone 1: ia, ib, d, e (partial), m, p, O, q ； Zone 2: ia, ib, d, e, m, p, O, q, n. The above symbols represent: ia, ib – intrinsically safe ； d-exploding-proof type ； e-safety enhanced type ； m-cure type ； p-positive pressure type ； O-oiled type ； q-sand-filled type ； n-sparkless type ； S-Special type. 2. The category and temperature group of explosion-proof electrical equipment shall be higher than the classification and grouping of explosive gases in hazardous environments. When an explosive mixture is formed by a substance with two or more flammability properties, explosion-proof electrical equipment should be selected according to the higher level and category of hazard. Explosive gases or vapors can be classified into three categories: IIA, IIB, and IIC, based on their Maximum Test Safety Gap (MESG) and Minimum Ignition Current (MIC). For example: Group IIA gases include methane, styrene, toluene, carbon monoxide, propylene, etc.—in the T1 temperature category ； Propylene, ethylbenzene, methanol, ethyl formate, etc.—T2 temperature category ； Butane, petroleum, fuel oil, ethanol, etc.—T3 temperature category ； Ethyl nitrite—T6 temperature group. Class IIB gases include: acrylonitrile – T1 temperature group ； Ethylene–T2 temperature group ； Butyraldehyde—T3 temperature group. Class II C gases include: hydrogen – T1 temperature group ； Acetylene–T2 temperature category ； Carbon disulfide—T5 temperature group. Categories of explosion-proof electrical equipment: ⅡC > ⅡB > ⅡA ； Temperature groups for explosion-proof electrical equipment: T6 > T5 > T4 > T3 > T2 > T1 ； In addition to the IIA, IIB, and IIC classifications for intrinsically safe and flameproof explosion-proof electrical equipment, no classification rules exist for other types of explosion protection.
CT4 is expensive; I’m not sure how much more the solenoid valves cost. However, the motor for CT4 is significantly more expensive than that for BT4. Don’t end up losing money on this, though sometimes losing money can be seen as a blessing:lol
Changing from IIB to IIC is an upgrade; it’s really honest business practice on the part of the supplier to not raise the price.