Grounding issue
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This is how I carry out grounding in the new factory facility: (1) The neutral wire of the transformer and its casing are connected together for grounding; (2) Around the distribution room, angle steel of 50X5 size and flat steel of 40X4 size are used to form a circular connection, which is then linked to the foundation anchors of the low-voltage distribution panel; (3) Several pieces of angle steel are installed near the crane tracks, and flat steel is used to connect these to the tracks; (4) The foundation anchors of the on-site distribution panels are connected to the tracks. The grounding systems of the distribution room and the tracks are not connected to each other. Is there any problem with this approach to grounding?
There’s a problem with the first rule: the neutral wire and the enclosure cannot be connected together before being grounded; they should be connected to the grounding system separately. Otherwise, in the event of a fault or similar issue, if current flows in the neutral wire, then current will also flow in the enclosure. If workers come into contact with the enclosure, they can get an electric shock, and the grounding of the enclosure will then be ineffective
(1) As mentioned above, the transformers are each connected to the grounding system. The tracks should be grounded at regular intervals and connected to the grounding grid, with more than 2 connection points; jumper wires should be used at the joints between the tracks. It is also best to connect the tracks, low-voltage equipment in substations, etc., to the grounding grid separately, thereby forming a combined grounding grid. It’s safer to use more material.
I’ve been learning by following tutorials, and I have a question from an outsider: what’s the difference between the ground wire and the neutral wire?
Grounding is used to prevent electric shock accidents caused by a charged enclosure. . It is based on safety considerations ； The neutral wire is the working line. Single-phase ~220 means that 1 live wire and 1 neutral wire are required to form a circuit. Three-phase unbalanced loads also require the neutral wire to carry unbalanced current. . . . In a three-phase balanced load, the vector sum of the three-phase currents exactly cancels each other out. So a neutral wire isn’t necessary! ~~!
Grounding should be connected to the grounding grid separately; as for the embedments, the depth and material also matter.
The requirement for existing low-voltage distribution systems is a TN-S system; that is, from the transformer to the low-voltage distribution cabinet, there should be three phase wires and five wires in total, including three phase power wires, one neutral wire, and one PE protection wire – this constitutes the standard configuration. When the low-voltage cabinet is installed, depending on the load requirements, there may be no neutral wire, but there must always be a PE wire. :victory:
The tracks, low-voltage equipment in the substation, etc., form a combined grounding grid. The remaining equipment is connected to the grounding grid via grounding wires respectively.
I’m sorry, but there’s no internet access here. Since this is an industrial facility, we use a TT system, and the grounding method should be fine. Also, I’d like to ask the moderator: why can’t I give ratings?