On-site control cabinet, explosion-proof electrical cabinet
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Is there anyone who is an expert in electrical engineering? I work in the field of process engineering and have a question I’d like to ask. In areas where there is a risk of explosion, control cabinets and power distribution cabinets need to be explosion-proof. Does this explosion-proofing refer to the cabinets themselves or to the electrical components inside them? If it’s only the cabinets that need to be explosion-proof, that’s simple; but if it’s the components inside that need to be explosion-proof, it becomes more complicated. Does anyone know the answer? Could you please let me know? It would be better to let us know where the standards are based on, by the way.
Use explosion-proof cabinets or positive-pressure fume hoods that meet the local explosion protection requirements; the components inside need not be explosion-proof. Of course, the simplest way is to avoid areas at risk of explosion, that is, by placing it more than 15 meters away from the source from which explosive substances may be released. For specific areas, refer to the explosion hazard zone classification diagram prepared by the electrical engineering team during the design process.
If the components inside the cabinet are not explosion-proof, such as ordinary relays, circuit breakers, PLCs, etc., then an explosion-proof or positive-pressure control cabinet is required. If the components themselves are explosion-proof, such as Huarong’s explosion-proof relays, the cabinet can be designed with enhanced safety features. If it is just a terminal box containing only terminals, an increased-safety type terminal box is generally used, as it facilitates maintenance and repair without the need to remove screws.
Bro, there’s a project here to relocate and renovate the control room. The cabinets and control panels were previously located in the on-site operation rooms within the equipment area, but they now need to be moved to the newly built area control room. The preliminary plan is to move all the original control stations and operation panels to the new control room, while replacing the positions where the control stations used to be in the original on-site operation rooms with transfer boxes. Multi-pair cables will be used to transmit signals to the new operation room, ideally with a one-to-one correspondence (each original control station corresponding to a specific transfer box). The transfer box needs to be explosion-proof; for now, enhanced safety type boxes are being used. How many signals can an enhanced safety type transfer box handle (what is the maximum number of input and output terminals)? Is it possible to establish a one-to-one correspondence with the original control stations?
This post was last edited by hl1357978 on 2019-12-23 09:20. If the PLC control cabinet is placed in a safe area and the cables coming from the field are armored, then: 1. Can this PLC cabinet be non-explosion-proof? 2: Are explosion-proof connectors needed for the incoming and outgoing wires of the PLC cabinet? Should all the incoming DI/DO signals be passed through isolation safety barriers? 3: If explosion-proof distribution boxes are used on-site, and there are many three-wire or two-wire photoelectric devices, does the distribution box need to have an explosion-proof interface for each of these photoelectric devices?