1. meets the grounding

Meets the grounding is refers to synthesis wiring system each kind of equipment and between the ground strap segment. All meets the grounding for the copper nature insulated conductor, its section should not be smaller than 4mm2. When the synthesis wiring system uses the shielded cable wiring, the information plug earth may meet grounding from Lian Zhimei using the cable shielding level achievement the level to match the line cabinet. When the synthesis wiring electric cable uses puts on the steel pipe or the metal line badly lays, the steel pipe or the metal line are bad should maintain the continual electrical connection, and should have the good earth in the beginnings and ends.

2. ground straps (level earth terminal)

The ground strap is the horizontal wiring meets the grounding to the system the public central junction. Each floor matches the line cabinet to be supposed to weld with this floor ground strap with the ground strap identical matches the metal which the space all syntheses wiring uses and the earth skeleton line should with this ground strap weld. The ground strap should be the copper generatrix, its most light-sized should be the 6mm thick ×50mm width, the length regards the project actual need to determine. The ground strap should use the electrotinning to reduce the contact resistance as far as possible, if is not the galvanization, then in fixes the wire to the generatrix in front of, must carry on the cleaning up to the generatrix.

3. earths skeleton lines

The earth skeleton line is draws out by the total ground strap, connection all ground strap earth lead. When carries on the earth skeleton line the design, should fully consider the building the structural style, the building size as well as the synthesis wiring route and the spatial disposition, and lays with the synthesis wiring electric cable skeleton line coordinates. The earth skeleton line should install in not physical and the mechanical damage protection place, in the building water pipe and the metal cable shielding level cannot take the earth skeleton line use. When in the building uses two or many vertical earths skeleton lines, between the vertical earth skeleton line each three and the top layer must with with earth the skeleton line constant section insulated conductor to weld. The earth skeleton line should for insulate the copper core wire, the smallest section should not be smaller than 16mm2. When when the earth skeleton line, its differential earth potentials is bigger than 1Vrm@S (有效�?, the floor matches the space to be supposed alone to use the earth skeleton line to meet to the host ground strap.

4. hosts ground strap (total earth terminal)

In the ordinary circumstances, each building has a host ground strap. The host ground strap took in the synthesis wiring earth system earths the skeleton line and the equipment meets the grounding the extension contact, its ideal position suitably supposes to the outwire introduction once in a while constructs matches the space. The host ground strap should arrange in the straight line way, simultaneously considered does not proclaim from the protector to the host ground strap welding wire excessively long. The earth directs the inlet, the earth skeleton line, direct current 配电�?to meet the grounding, the outwire introduction all meets the grounding, as well as identical matches metal with the host ground strap which the space all syntheses wiring uses to be supposed and the host ground strap good welding. When the outwire entrance cable has the shield or puts on the metal 保护�? this shield and the metal tube also should weld to the host ground strap. The host ground strap should use the copper generatrix, its smallest section size is 6mm the thick X100mm width, the length visible project actual need decides. Is same with the ground strap, advocates the ground strap also to be supposed to use the electrotinning to reduce the contact resistance as far as possible. If is not the galvanization, then the host ground strap in fixes must carry on the cleaning up to the wire in front of.

5. earths directs the inlet

The earth directs the inlet to refer to the host ground strap with to meet between the terrain the ties, suitably uses the 40mm width ×4mm is thick or 50mm×5mm galvanizes the flat steel. The earth directs the inlet to be supposed to make the insulation antiseptic treatment, should have in its unearthed spot guards against the mechanical damage measure, also not suitably puts with the warm air pipeline with the ditch cloth.

6. meets the terrain

Meets the terrain to divide the nature to meet the terrain and artificially to meet the terrain two kinds. When the synthesis wiring uses the alone earth system, meets the terrain generally to use artificially meets the terrain below, and should satisfy the condition:

(1) meets the terrain from the labor frequency low pressure exchange power supply system not to proclaim is smaller than 10m.

(2) meets the terrain from the building anti-radar system not to be supposed to be smaller than 2m.

(3) the earth resistance should not be bigger than 40 Omega.

When the synthesis wiring uses the union earth system, meets in the terrain general use building foundation 钢筋�?to meet the terrain as the nature, its earth resistance should be smaller than 1 Omega. Usually uses the union earth system in the practical application, this is because compares with former, the union earth way has following several remarkable merits:

(1) when the building suffers is struck by lightning, in the floor each potential distribution quite is even, the staff and the equipment peaceful versatilely obtains a better safeguard. At the same time, the building portal frame construction provides 10 ~ 40dB to the center wave electromagnetism field energy the shield effect.

(2) is easy to obtain the smaller earth resistance.

(3) may save the metal material, 占地 are few.

Carries on several questions which the synthesis wiring system the earth design should pay attention

When 1. syntheses cities line system uses the shield measure, all shields level should maintain the continuity, and should pay attention to between the guarantee wire the relative position to be invariable. The shield level commutation equipment (FD or BD) the end receives, the user (terminal device) looks carefully the special details directly, beginnings and ends earth: Should connect as far as possible to identically meets the terrain. When in the earth system has two, when different meets the terrain, its differential earth potentials should not be bigger than 1Vr.m.S (有效�?.

2. when the electric cable enters the building interior from the building to be easy to receive is struck by lightning, when power source 碰地, power source induced e m f or earth potential 上浮 substandard factor influence, must use the protector.

Below 3. when the line is in any kind of dangerous environment, should carry on to it has pressed has flowed the protection:

(1) is struck by lightning the dangerous influence which causes.

(2) the working voltage surpasses 250V the power source line 碰地;

(3) the earth potential rises the power failure which causes to 250V above;

(4) exchanges the 50HZ induced tension to surpass 250V.

4. syntheses wiring system 过压保护 suitably selects the gaseous tube protector. Because in the gaseous tube protector ceramic outer covering seals has two electrodes, during has the electric discharge gap, and sufficiently has the inert gas. When between two electrodes potential differences surpass the 250V alternating voltage or the 700V thunder and lightning surge voltage, the gaseous tube starts to appear the electric arc, and 地电�?between has provided a conductive path for the conductor.

5. syntheses wiring system the class has protected suitably selects can from the duplicate protector. Because on the electric cable possibly appears like this or such voltage, if the interconnection equipment has provided for it to the place low resistivity circuit, then is insufficient to cause 过压保护 the movement, but it produces the electric current actually possibly damages the equipment or causes the fire. Example: The 20V electricity line of force is possibly insufficient to cause 过压保护 the electric discharge, but has the possibility to have the big electric current input media interior to create the destruction, therefore while uses 过压保护 must use has flowed the protection. The request uses can from duplicate flow the protector, mainly is for the convenience maintenance.

In brief, along with intelligent construction unceasing development, the people will certainly to its earth system to set a stricter request. Will say regarding the general engineers and technicians, enhances the synthesis wiring earth system the stability and the reliability will be an item long-term and the arduous duty. The road is endless its 修远 about, we need seek.