Regarding the notation for explosion protection ratings

Your understanding is basically correct. "The notation “Ex d IIB T4 Gb” – under IEC standards, all the details related to this classification are usually indicated on the component itself, thereby providing a more detailed description of the device’s explosion-proof properties. Dense dates are divided into two main categories; “Ga” denotes equipment safety, meaning there is no possibility of explosion under either normal or abnormal operating conditions ； "Gb” denotes device safety, meaning that an explosion is impossible only under normal operating conditions; fault conditions are not included. Therefore, “Ex d IIB T4 Gb” means that the device is an explosion-proof device, with explosion protection achieved through separation; “IIB” identifies the gas group, “T4” denotes the temperature group, and “Gb” indicates the device’s explosion safety level, ensuring that an explosion is impossible under normal operating conditions. Thus, “Ex d IIB T4” omits the equipment’s explosion protection rating to some extent; however, generally speaking, explosion-proof equipment is usually classified under “Gb”, so it can be understood as having the same meaning. However, to avoid any possible confusion, it is more accurate to follow the instructions of the equipment manufacturer and the regulations set by the International Electrotechnical Commission (IEC) or other relevant organizations when stating the explosion-proof rating of the equipment in full, thereby ensuring that all parties involved can clearly understand the correct classification and usage conditions of the equipment. If professional clarity is required or you need to explain these devices to others, it is better to use the full names in a detailed and accurate manner. .