How should the cross-sectional area of the control cable for the ammeter on the operation column be selected? ?
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A current transformer with a secondary side current of 1A is installed in the distribution cabinet of the substation. An ammeter is installed on the field operation panel, which is located 260 meters away from the substation. Questions: 1. Is it acceptable to use a copper cable with a cross-sectional area of 2.5 square millimeters for the control cable leading to the ammeter on the field operation panel? 2. Can the wire core of the current meter at the operation column share the same control cable as the wire cores of the control buttons and signal lights at the operation column? The ammeter on the field operation column is of the pointer type.
1. A 2.5 square millimeter wire will suffice. 2. The low-voltage AC circuit can share the same cable as the control line ； High-voltage motors equipped with DC control should use separate current circuit cables whenever possible.
Answer: 1. A 2.5-square-meter control cable can be used. 2. A multi-core control cable can be used.
This post was last edited by mui on 2019-12-19 at 14:08: 1. It is correct to choose a current transformer of type 1A; 2.5 square millimeters should be sufficient. 2. Are the wires of the ammeter, as well as the control buttons and signal lights on the control panel, of the same voltage type or rating?； If different, it is recommended to use a computer cable
Around 260 meters; for the secondary side of the current transformer, 1A should be selected. Use 1.5 mm² control cables, and employ two-core cables for the ammeter circuit. If a 2.5 mm² control cable is chosen, that will also work; it just has more conductors, which results in a larger cross-sectional area for the control cable. Personally, I don’t think it’s necessary to use 2.5 mm² cables just for operating ammeters on-site; it increases costs. With more conductors, the cable cross-section becomes larger, which makes installation easier but also takes up more space in the cable tray: lol
Around 260 meters; for the secondary side of the current transformer, 1A should be selected. Use 1.5 mm² control cables, and employ two-core cables for the ammeter circuit. If a 2.5 mm² control cable is chosen, that will also work; it just has more conductors, which results in a larger cross-sectional area for the control cable. Personally, I don’t think it’s necessary to use 2.5 mm² cables just for operating ammeters on-site; it increases costs. With more conductors, the cable cross-section becomes larger, which makes installation easier but also takes up more space in the cable tray: lol