Technical specification for wiring of Small Power Distribution Unit (SPDU)

1. The conductor in the Small Power Distribution Unit (SPDU) shall be correctly connected to the designated terminal in strict accordance with the identification of the drawing.

2. Wire

A. The conductor section of the main circuit shall be identified according to the drawing. The conductor section of the control circuit is 1mm2 and that of the multi-core cable is 0.3mm2.

B. Conductors above 4mm2 (inclusive) are of black RV type, conductors below 4mm2 are of white RV type, and the color of cable sheath is black.

C. Special wire stripping tools shall be used to strip the wire insulation, and the wire core and the UN stripped insulation shall not be damaged. The notch shall be flat.

D. Set the insulation stripping length of the wire end as L. when the wire end is inserted into the terminal, take the length L1 of the wire core inserted into the tubular joint sleeve plus 1 ~ 2mm, i.e. L = L1 + (1 ~ 2). When the wire is stripped and crimped with the terminal, all copper wires must pass through the terminal sleeve, and the wires below 0.5mm2 must pass through the terminal sleeve after being folded in half.

E. For conductor joints that cannot use terminals, solder shall be applied after insulation stripping. Intermediate butt joint shall not be allowed during conductor laying. When butt joint is required in special occasions, welding method must be used, and heat shrinkable tube protection shall be provided after welding.

F. When connecting wires and components, the shortest path shall be selected. The wiring of PLC input circuit in the cabinet shall not be laid in the same trunking as the control lines of main circuit and other voltage grade circuits.

G. The wire is connected with the panel element, and the wireless slot of the panel shall be protected by winding pipe. When the panel harness is connected with the cabinet, it shall be considered that the harness shall not be subject to friction when the cabinet door is opened and closed.

H. Avoid connecting several wires to the same terminal. There shall be no more than 2 wire joints on the same terminal on the element. When two wire joints are connected to the same terminal, the contact shall be flat and good.

1. When there are many wires of the same wire number and it is impossible to fasten them all on the terminal, multiple crimping terminals can be used, but this method is only suitable for the control wire.

J. For the welding between conductor and grounding plug, solder shall be applied on the conductor and connector first, the welding shall be firm and reliable, and the welding place must be protected by heat shrinkable tube.

K. The conductor shall not be squeezed into a groove, and the conductor shall not be subject to additional tension.

3. Terminal

A. Cold pressed terminals must be pressed on the connection between wires and components. Except under special circumstances, the wires shall not be stripped and directly connected to devices.

B. The diameter of the wire number tube of the terminal must match with that of the conductor, and the shape of the connecting port must match with that of the component terminal post. Fork terminals can be used for control circuits. Ring terminals must be used for motor terminals, heating power terminals, grounding terminals and some main circuit terminals to increase the contact area, and needle terminals must be used for some connectors.

C. Special terminal crimping pliers must be used for terminal crimping, and the crimping interface used during crimping must match the terminal. After crimping, the contact between conductor and terminal must be good and firm.

D. After the wire terminal is crimped and connected with the element, it shall pass through the nearest trunking tooth, and the included angle with the end face of the element shall be maintained at 90 °, and the inclination shall not exceed 5 °.

E. When the terminal is connected with the element terminal, it shall be inserted into the terminal as far as possible, the contact shall be flat and good, and the torque used for screw fastening shall be appropriate.

F. All terminals must be sleeved with wire number sleeves. After crimping the main circuit terminals, if the sleeves cannot be sleeved, heat shrinkable tubes shall be used for protection.

4. Wire number sleeve

A. The wire number sleeve has two functions: one is to protect the insulation of the crimping part of the bare terminal, and the other is to mark the wire number of the conductor.

B. The selection of wire number bushing must match the conductor section. When printing the conductor number, the font size selected must match the pipe diameter of the bushing.

C. The length of control circuit wire number is 25mm, and the diameter of main circuit bushing is φ The length of 5mm wire number is 30mm.

D. Before crimping the terminal, the printed wire number sleeve must be put on first. The sleeve should cover the bare terminal sleeve part by more than 1 ~ 1.5mm, and the font direction is parallel to the front of the element.

E. After the terminal is fastened, the corresponding wire number is read from bottom to top when viewed in the vertical direction; When viewed in the horizontal direction, it reads from left to right.

F. The wire numbers at both ends of each wire are unique. It is strictly prohibited to have different wire numbers on one wire.

G. When the cross section of the conductor is large and the corresponding sleeve cannot be selected, the nylon tie can be used to fix the sleeve on the conductor. The reading flow direction is the same as above, and the same method is used for the marking of the cable.