How To Prevent Poor Contact Of The Neutral Block?
Poor contact of the neutral block can easily cause abnormal heating, unstable voltage, and even electrical fires in equipment. It is necessary to control the entire cycle from design to maintenance:
Material selection control
Choose copper silver plated terminals or copper aluminum transition joints, whose conductivity is 1.6 times that of ordinary brass. The cross-sectional area of the wire should match the terminal specifications. For cables larger than 16mm ², it is recommended to use crimped terminals to avoid virtual contact caused by winding wiring.
Installation process
Adopting the double bolt locking method: pre tighten at 80% of the standard torque value for the first time, and finally tighten at full torque value for the second time, ensuring that the crimping area is greater than 1.2 times the cross-sectional area of the wire. After installation, an infrared thermometer is needed to detect the temperature rise. If Δ T>20 ℃, rework is required.
antioxidant defense
In humid environments (RH>70%), an electric composite grease should be applied to form a sealing layer. It is recommended to upgrade the use of silver tungsten alloy terminals in coastal or chemical sites, as their salt spray corrosion resistance is 40 times higher than that of ordinary copper terminals.
intelligent monitoring
Install temperature sensor+AI diagnostic module to monitor real-time changes in contact resistance. When the resistance value exceeds 1.5 times the initial value, an automatic warning is issued with an accuracy of 0.01m Ω, which is 6-8 months earlier than traditional manual inspection to detect hidden dangers.
Maintain standards
Establish a "three-year full inspection+annual sampling" system and use torque calibrators to check the tightening status of bolts. After each maintenance, a current test must be conducted to ensure that the current carrying capacity reaches 95% or more of the nominal value.
By implementing the above measures, a certain power grid company has reduced the zero line terminal failure rate from 0.83% to 0.09%, saving over one million yuan in annual repair costs.
