Discussion on equipotential grounding
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I’ve just taken on a project. In just over 300 words, here’s the main point: The design requirements regarding grounding are as follows – since the motor is powered by a three-core cable, three wires must be used for the conduit installation. 1. Power cable. 2. Protective grounding (from the main grounding network to the equipotential grounding plate, and then connected to the equipment with flexible wires). 3. Neutral grounding (a flat steel bar is run from within the cable tray and then connected to the equipotential grounding plate). Are two equipotential grounding plates sufficient? Does a three-core cable necessarily require the neutral wire to be grounded? I seek advice from experts.
Is the motor 220V or 380V? Why a three-core cable? What does it mean to bury three pipes?
The model of the motors is not known yet; the drawings have not been received. From the wiring diagram, it can be seen that the smaller motors have a power rating of a few kW, while the larger ones have a power rating of around 60 kW. A three-core cable refers to the cable that supplies power to another cable. (The cable model specified in the design) Burying three pipes means: 1, power cable (three-core cable). 2. Use BVR wire for protective grounding. (From the grounding main network to the equipotential ground plate, and then connected to the equipment with flexible wires). 3. Neutral grounding BVR wire (led out from the tray using a flat steel bar and then connected to the equipotential grounding plate). I want to know: why must a three-core cable emerge from the grounding flat steel bar in the tray?
What you’re describing sounds a bit strange; I’ve never seen such a design. I wonder which design firm came up with it? We usually use 4-core cables, without a neutral wire, only a protective ground wire. Then perform repeated grounding.
There is indeed a problem with the design. It mainly depends on the power supply system you use; it seems to be a three-phase five-wire system, with three power lines – one N and one PE. A 5-core cable is already available; why must 3 pipes be buried? In this system, the N and PE wires are connected at the distribution cabinet, and then repeated grounding is done at the equipment. Increase protection for equipment and personnel. Raise objections with the design institute; some of them design carelessly, and their designers lack experience. Following their suggestions will result in higher costs