Cable length calculation rules
In the process of laying the cable, whether it is through the pipe laying or laying in the bridge, the cable is not in a completely straight state, it is laid with a certain degree of relaxation, waveform curvature crossing, etc., then we need to calculate the length of the cable when this length is also counted, according to the calculation rules, the laying coefficient is 2.5%.
Then the total length of the cable should be: (total cable length + reserved length) * 1.025
How is the reserved length calculated?
Note: The additional and reserved length of the cable is an integral part of the cable laying length and should be included in the cable length engineering quantity. That is to say, the additional length of cable laying relaxation, waveform curvature and intersection should be calculated based on the sum of the horizontal and vertical laying lengths shown in the design diagram plus the reserved lengths.
1 Cable slack, waveform arc, crossing
Cable laying relaxation, waveform curvature, etc., require an additional factor of 2.5% of the total length.
2 Cables into the building
Mainly when the outer line of the municipal road (or the traffic safety engineering cable) enters the site, it is necessary to consider the minimum value of 2m reserved by him.
3 The cable enters the trench or hanger
When the cable enters the trench or hanger, the minimum value of the upper (lower) reservation is 1.5m.
4. Incoming and outgoing lines of substation
Consider reserving a minimum of 1.5 m
5 Cable terminations
The minimum value of the power cable termination is 1.5m. Reserved for overhauls
6 cable mid-header
Leave 2m at each end of the splice box in the middle of the cable. Reserved for overhauls
7. Cable inlet control, protection screen and analog panel, distribution box, etc
Cable inlet control, protection screen and analog panel, distribution box, etc. According to the disk surface (or box surface): height + width, that is, the half circumference of the computer we commonly use.
8. High-voltage switchgear and low-voltage switchboard and box
For high-voltage switchgear and low-voltage switchboard and box, consider 2m of inlet and outlet lines under the panel.
9 Cable to motor
Cable to motor: +0.5m from motor junction box.
10 Factory transformers
厂用变压器:从地坪算+3m预留
11 Cables bypass beams and columns, etc
The length of the cable is increased by bypassing the beams and columns, etc., and the length is increased according to the cross-section of the winding object.
12 Elevator cable and cable rack fixing point
Elevator cable and cable rack fixed point, 0.5m each.