Poor Contact Of Terminal Blocks? These Solutions To Help

Poor contact of terminal blocks is a common problem in electrical connections, which can lead to equipment malfunctions, overheating, and even safety accidents. The following analysis will be conducted from two aspects: the cause of the problem and targeted solutions, to help quickly locate and solve the problem.

1、 Common causes of poor contact

Surface oxidation or contamination:

Long term exposure of the terminal metal surface to humid or corrosive environments can easily form an oxide layer or accumulate dust, leading to an increase in contact resistance.

Insufficient fastening force:

The screws are not tightened or loose, causing gaps between the wires and terminals, resulting in local overheating when current passes through.

Mismatch of wire material:

When copper wire is directly connected to aluminum wire, the contact surface deteriorates due to electrochemical corrosion.

Vibration or external force influence:

Vibration or human error during equipment operation may cause loose terminals.

2、 Targeted solutions

Cleaning and protection:

Clean the oxide layer: Use sandpaper or specialized cleaning agent to polish the surface of the terminal and remove the oxide layer.

Applying conductive paste: Apply conductive paste on the contact surface to reduce oxidation and decrease contact resistance.

Enhance fastening force:

Regular inspection: Use a torque wrench to re tighten according to the standard value (such as 1.2-1.5N · m for M4 screws).

Anti loosening design: using terminals with spring washers or anti loosening nuts to reduce looseness caused by vibration.

Material matching and transition:

Avoid mixing copper and aluminum: If connection is necessary, use copper aluminum transition terminals or tin plated copper joints.

Choose the appropriate wire diameter: Ensure that the cross-sectional area of the wire matches the rated current of the terminal to avoid overload heating.

Optimize installation environment:

Moisture and dust prevention: Use sealed terminal boxes or install dust covers in humid environments.

Reduce vibration: Install shock-absorbing pads on vibration source equipment or switch to seismic resistant terminals.

3、 Preventive measures

Regular maintenance: Check the terminal fastening status and contact surface condition every six months.

Choose high-quality terminals: prioritize terminals made of corrosion-resistant materials such as nickel plating and silver plating.

Standard operation: When wiring, ensure that the wire stripping length is appropriate (usually 8-10mm) to avoid copper wire exposure or loose crimping.

Through the above methods, the problem of poor contact of terminal blocks can be effectively solved, and the reliability and safety of electrical systems can be improved.