【正文】 ounding, multiple branching of single point grounding. 2 single point grounding method Tandem type single point grounding: or first grounding ways. Method : the number of low voltage electrical equipment grounding terminal equipment with the same root near the ground wire connecting, then through this grounding and grounding device. The grounding system is: save manpower, material resources。 Grounding。 1 Lightning protection grounding Abstract The significance of lightning and mitigation on very little money to prevent large losses, and its function is to use scientific means avoid natural disasters. Grounding is to make the system has been included in the lightning protection lightning energy discharge into the earth, and good grounding can effectively reduce the online guide overvoltage, avoid counterattack. Avoid ground is the most important aspect of technology, whether sings rem, induction lightning, or other forms of ray, ultimately the lightning current into the earth. Therefore, no reasonable and good grounding device is can39。t reliably the lightning strikes. The smaller the grounding resistance, e loose flow is quicker, lightning objects the time to maintain high potential more short, the less risk Key Words: Lightning protection。 Current。 while the disadvantage is that: when the public grounding line open circuit, if the grounding system has a device leakage, can cause other equipment which occurred on voltage, a threat to the safety of personnel. Backup ground terminal introducing a grounding line, and then the number of lines at the same time received a grounding device. The grounding system is: when the grounding system in which a device grounding wire broken circuit, will not cause other equipment enclosure voltage, to ensure personal safety. This grounding mode is: if it is not perfect on the interference of high frequency electronic equipment or other highly sensitive electrical equipment, high frequency interference from other devices ( such as converter, intermediate frequency stove thyristor converter parts) will be from the mon place of string, causing the device is not working properly. Multiple branching of single point grounding: or third grounding ways. Grounding method: each equipment grounding terminal alone received a grounding device. Earthing method and second kinds of grounding is the difference: the device has a separate grounding body ( or a change of: received directly from the grounding body recent grounding device ( or grounded source office ), each device in the electrical ground loop on the distance is far more (for example, more than 50meters ) ). This effectively avoids the mutual electrical equipment Magic this grounding mode timeconsuming, laborious and separate grounding the source is not good for. 3 In the usual construction, in fact the grounding of PLC way adopts the second grounding ways, as for electromagic interference: if the cabi is provided with a plurality of high power frequency converter, can be in the PLC power supply is installed in front of a singlephase power filter can be, generally designed in the inverter PLC near the front end are equipped with power supply filter. The interference effect of DC and AC equipment, can be connected together even if the DC and AC circuits because of some reason connectivity, because they are not the same as a loop ( grounding is not part of the loop ), will not cause damage to the equipment. People have AC220V power and DC24V circuit connected to it, but the equipment work remains normal. Digital and analog ground suggested separately ( unless you39。 (2) each welding head。 (4) the horizontal grounding body,Anti corrosion measures,grounding body using copper, copper clad steel earth body or hot galvanized materials。 use of cathodic protection. One, ground resistance test requirements: a. AC grounding, grounding resistance should be less than4 ohm。 C DC grounding, grounding resistance should be according to the puter system specific requirements determined。 e for shielding system if the joint grounding, grounding resistance should not be greater than1 ohms. Two, ground resistance tester ZC8grounding resistance meter is used for measuring the power system, electrical equipment, lightning and grounding resistance value. Also measuring low resistance conductor resistance and resistivity of soil. In three, the instrument by hand generator, current transformer, a slide wire resistor and galvanometer etc., all arranged in the plastic shell body, and the shell is convenient for carrying. Accessory auxiliary probe wires, installed in the accessory working principle of the voltage paring type. In four, before use to check whether the plete tester, tester prises the following device. In 1, ZC8 type grounding resistance tester, a2auxiliary grounding rods two root of 3,5m,20m,40m wire a Ground resistance tester, usually hand ZCXX series, including a short black lines, a20M line, a40M line, testing line connected at one end of a tested object whose the other end is connected with a shake table on each of two short connecting terminals, and the remaining 2terminal 20M line with P terminal,40M line C terminal to terminal, after the 20M and 40M line according to the ribbon (that is, to shake table for the endpoint of a triangle ) or linear pletely out, hit