Article 520. Lightning and earthing Wire
Refer to Section 5 for the overhead ground wire in this Guideline.
Section 4 INSTALLATION OF INSULATOR AND WIRING ACCESSORIES
Article 521. Installation of insulator
Insulators should be lifted up right before the conductor is fixed to them to prevent the damage. Insulators should be protected by cloth sheetto avoid being damaged by the contact between insulators, with the pole and the conductor.
The standing insulator should be confirmed thatthe insulator endures the bending force by the maximum tension of the conductor at the bend location on the line.
Section 5 INSTALLATION OF CONDUCTION WIRE AND LIGHTNING SYSTEM
Article 522. Protection of wire
The conductor gripper is the part where strands ofa conductor are cut easily due to the vibration by slight wind. Especially, it tends to be cut easily at the suspension clamp, the strain clamp of a copper conductor and the strain clamp of a thin aluminum conductor with cross sectional area of 100mm2 or less.
As a preventive measure from strands of the conductor being cut off, there is a method of winding the armor rod which is the same material as outer strands of the conductor at the grip section. The armor rod should be wrapped tightly to the edge so thatthe decentering at the center position is 5 cm or less, and there is no strand gap.
The example of the tying to the standing insulator is shown in the following figure.
(In case of a bare copper conductor) |
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(In case of a insulated conductor) |
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Figure 522 (Sample) Tying to the standing insulator
Article 523. Requirements for specification of wire
Cross sectional area of the supporting wire should beselected to have the strength to bear the pole or the conductor, and should not be less than the design material.
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The connection of supporting aluminum wire or supporting aluminum wire with steel core should be in accordance with the connection of the conductor. (Refer to Article 524 in this Guideline)
Article 524. Connection of wire
Refer to the requirements for connection of the conductor in Chapter 3-3 in Technical Regulation Vol.1.
However, the cable with voltage up to,000V,1 communication network, roadway network and railway network, etc., and the conductor with cross sectional area of240mm2 or more are allowed to be connected within the span on heavy traffic roadwayThe. connection is prohibited around clamps where there is the contact between the connection part and the clamps, the tiredness by the vibration and the interference of installation of the damper, the distance between the connection point and the clamp should be 5 m or more.
The connection sleeve which has defects by the manufacture or the compression work should not be used
Article 525. Jointing pipe
The connection of conductors should be confirmed as shown in following table.
Table 525 Connection of conductor
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Confirmation contents |
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Position of connection sleeve |
According to the specifications. |
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Cutting length of steel core |
According to the standard cutting gauge. |
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Diameter of compressed sleeve |
According to the compression gauge. |
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Displacement of sleeve |
The center point of a sleeve should be at the center point of |
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the connection. |
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Tying of soft aluminum wire |
According to the specifications |
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Polishing conductor |
There is no problem with the electric characteristic. |
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Aluminum conductor : 7 to 12 % |
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(Reference value) |
Steel core of conductor : 18 to 23 % |
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Copper conductor : 8 to 13 % |
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Expansion of conductor |
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However, it is acceptable for the expansion ofthe conductor |
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when there is no significant difference. |
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Article 526. Heat fusion welding method
The cable connections by welding should be ensured the expected strength and damp-proof carefully. The cable shall be sufficiently cleaned up not to penetrate impuritiestointhem. The connection by
heat fusion welding method shall not be conducted at points with mechanical loads are |
stressed |
because the mechanical strength of the connection points are very weak. In addition, If the connection |
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points by heat fusion welding method are loaded mechanically, the connection points |
shall be |
removed in advance and exchange other connections (connection sleeves, etc.) with |
sufficient |
mechanical strength. |
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Figure 526 Heat fusion welding method
Article 527. Wiring work
The strength andthe power transmission capacityof the conductorare reduced greatly when the conductor is damaged. To avoid this, theconductors should be in the state that makes them pending with pulleys etc., and avoid the contacto ground and the plant in the string work. The offset distance from the conductor tothe road should be in accordance with Article291 in Technical Regulation Vol.1.
Article 528. Installation of power wire and lightning wire
In the sag of conductors and overhead ground wires, the difference from the design value should be within 10 cm.In addition, in case of multiple conductors,the difference of the sagbetween the conductors should be smaller than the external diameter of the conductor.
Article 529. The distance from power wire to ground
The offset distance fromthe conductor to the ground, the pole, and the other conductor should be in accordance with Chapter 3-3 in Technical RegulationVol.1.
Section 6 NUMBERING AND PAINTING
Article 530. Painting for anti-rust
The metallic part of steel tower, etc. should be conducted antirust treatment to prevent reducing the strength due to rust.The antirust treatment includes galvanizing or antirust painting, and should be conducted under proper management at the factory.
The following parts should not be painted.
-The connection of the earthing conductor : The earthing resistance might be increased by painting.
-The part buried in concrete : The adherence between the part and concrete might be reduced by painting.
The painting should not be mixed with the water or the foreign substance becausethese substances cause the reduction of the painting quality and hastening progression of rust.In addition, the painting should not be executed at the low temperature that the paint can not dry and harden properly.
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Table 530 Prohibited condition of painting |
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Items |
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Prohibited condition of painting |
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When the rain or the snow might fall before the paint dries firmly. (The paint |
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Weather |
should be dried until it does not adhere to hand when it is touched.) |
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When it is windy or whenthere are a lot of dust because foreign substances are |
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mixed with the paint easily. |
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When the air temperature is 5deg C or less. |
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Temperature |
When the temperature of the metal |
part significantlyis high due to sunlight |
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because the paint |
causes bubbles by |
the heat, and it is impossibleo tpaint |
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properly. |
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Humidity |
When humidity is 85% or more. |
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When the metal part has the humidity by rain or dew. |
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