Grounding Device Inspection and Maintenance
After a newly installed grounding device is completed, it must be inspected before being put into use. The first step in inspection is to visually examine the exposed parts of the grounding device, such as whether the grounding wire is intact, the color is correct, and whether it is flat, continuous, and without breaks. The connection between the grounding wire and the grounding electrode (or, for anti-static grounding, the entire grounding grid and grounding wire) should be checked for reliable contact, whether the welding meets requirements, and whether the wall bushing has anti-corrosion measures.
The second step is to measure the grounding resistance. There are many methods, but the following are generally simple methods:
1. Grounding resistance measuring instruments
2. Ammeter-voltmeter method
3. Ammeter-electric meter method
4. Bridge method
5. Three-point method
Each method has its advantages and disadvantages; the method used depends on the available instruments. However, methods using dedicated resistance measuring instruments are generally preferred because they have their own power supply, are portable, provide continuous readings, are simple to use, and come with auxiliary grounding electrodes and grounding rods. This type of device is designed with very low resistance, effectively eliminating the influence of stray currents at the boundary. Currently, the ZC-8 and ZC-29 models produced in my country are actually ZC-8 type grounding megohmmeters. However, instruments are often limited by their resistance values. Therefore, when the measurement range is large, the ammeter-voltmeter method can be used. Its range can measure from 0.1 ohms to over 100 ohms, making it more suitable for measuring the low resistance grounding requirements of telecommunications equipment rooms.
Grounding device maintenance: Grounding devices should be inspected regularly. In the first year, measurements should be taken monthly. After one year, intervals can be appropriately extended, but should not exceed six months. The main checks include the tightness of connections, corrosion protection, and the reliability of insulated conduits.
Since anti-static grounding is one aspect of all grounding, to illustrate the relationship between anti-static grounding technology and its grounding system, other grounding issues have also been introduced. However, this is not a complete overview of grounding technology.