Jack knowledge about cable:knowledge of ground wire

In life, the ground wire is more commonly used as a cable, Here we give a brief knowledge of the ground wire! 
Ground wire is directly connected to the earth wire, also called safe return route, it put pressure direct danger to pass the Earth, considered a lifeline. 
Household appliances due to the poor insulation or humid environment will cause its shell with a certain static, in severe electric shock. In order to avoid such occurrences in the electrical wires may be connected to a metal housing at the other end of the wire to earth, once the electrical leakage occurs into the static ground line will release the earth. In addition to electrical maintenance personnel in the use of electric iron welding circuit, sometimes because of the charged electric iron and damaged electrical breakdown of the integrated circuit, which is more important. Friends sometimes use the computer to ignore the main case is grounded in fact, connected to the host computer root shell ground, to a certain extent, can prevent crashes phenomenon. 
In the power system ground: an important tool to have when the power voltage of equipment and lines appear unexpectedly assurance staff. By ministerial regulations, the ground wire must be more than 25mm 2 soft bare copper wire.

Brief introduction

Appliances, ground wire is connected to the electrical equipment enclosure and other parts in a timely manner will be due to various causes unsafe charge or leakage current export lines.

(1) high-voltage ground wire effect: high ground wire is used for lines and substation construction, to prevent near the charged body to ensure the safety of the use or misuse of electrostatic induction shock closing time. 
(2) high-voltage ground wire structure: portable high voltage ground wire from the insulated operating rod, wire clips, short routes, grounding wire, grounding terminals, bus clip, earth clamp. 
(3) high-voltage ground wire production process: the fine craftsmanship - wire clamp, earth clamp is made of high quality aluminum die casting; operating rod using epoxy color tube, good insulation properties, high strength, light weight, bright appearance smooth; soft ground using multi-strand copper wire twisted together high quality soft, and covered with soft, high temperature transparent insulating sheath can be worn on the ground to prevent the use of copper, copper wire fatigue testing requirements, ensure workers safety in operation. 
(4) ground wire Specifications: according to ministerial regulations, the ground wire must be more than 25mm 2 soft bare copper wire.

Resistance requirements

High short-circuit ground wire to ground resistance requirements determine the quality of the ground wire, generally in accordance with the power industry DL-T879-2004 technical requirements of each cross-sectional area of ​​the ground wire to ground resistance is not greater than the following values: 
DC resistance is measured between the lugs, 
For 16mm2, 25mm2, 35mm2, 50mm2, 70mm2, 95mm2, 120mm2 various sections, 
Average per meter were less than the resistance value should 1.24mΩ, 0.79mΩ, 0.56mΩ, 0.40mΩ, 0.28mΩ, 0.21mΩ, 0.16mΩ.

High voltage ground wire classification

(1) high-voltage ground wire in accordance with the use of the environment can be divided into: indoor busbar grounding wire (JDX-NL) and outdoor line-type ground wire (JDX-WS). (2) high-voltage ground wire in accordance with the voltage level can be divided into: 10KV ground wire, 35KV high voltage ground wire, 110KV grounding line, 220KV high voltage ground wire, 500KV high voltage ground wire 
Instructions for use 
(1) When mounted ground: first link earth clamp, followed by electrical connection clip; When removing the grounding line, the program must first disconnect power clip, after the demolition of the grounding clip. 
(2) Installation: soft copper phase grounding copper nose on his eyes fixed on the ground rod grounding Clips (electrical connection there are the fixed and movable) corresponding position on the monocular copper nose on the ground conjunct fixed on the ground or ground pin clip, constitute a complete set of ground wire. 
(3) verification of voltage levels and ground rod to operate the equipment are the same voltage level. 
(4) Ground partakers with soft copper and modular, grounding rods have flat type and double reed hook clamp.

Maintenance

Before using portable short-circuit ground wire should confirm a priori power outage, make sure no voltage on the device after the. First grounding clamp connected to the ground network or flat iron, then stick with a ground operation wire end line classes were tightened on the device leads. When removing the short-circuit ground wire, coinciding with the opposite order. 
Short-circuit ground wire installed from it and live equipment, taking into account the impact of the grounding wire pendulum, its safe distance should not be less than the value of the new regulations, "electricity safety regulations."

Prohibited method but with winding is shorted to ground without clamp.

Suspension points if ground, use copper for grounding clamp or a dedicated ground connection; If no fixed ground available; are available temporary grounding, grounding buried depth should not be less than 0.6m. 
Portable short-circuit ground wire should be properly kept. Before each use, check carefully whether it should be in good condition, no bare annealed copper wires exposed, no loose nuts shall not be used. 
Portable short-circuit ground wire test cycle every five years, with factory inspection test items. After passing the test of portable short-circuit ground wire after being subjected to short-circuit, short-circuit current withstand should be based on the size and appearance inspection judgments in general should be scrapped