HSE DOCUMENTS-CONTACT RESISTANCE TEST FOR BUS DUCT FORM AND PROCEDURE

 

Why contact resistance test is essential? 

A. A contact resistance test is essential for assessing the quality and performance of electrical bus ducts. 

B. It helps identify potential issues with electrical connections within the bus duct, ensuring the system's reliability and safety. 

The following is a basic procedure for conducting a contact resistance test on a bus duct:

Remember: 

1. Before performing any electrical tests, make sure you are a qualified electrician or have the necessary training and equipment to safely conduct these tests. 
2. Ensure the bus duct is de-energized and properly isolated before starting the test.

Equipment Required:

• Digital Multimeter (DMM) with low-resistance measurement capability (mΩ range).
• Kelvin test leads (four-terminal measurement) to minimize lead resistance.
• Safety equipment, including gloves, safety glasses, and appropriate personal protective equipment.

Procedure:

Safety Precautions:

• Ensure that the bus duct is completely de-energized and properly locked/tagged out to prevent accidental energization.
• Wear appropriate personal protective equipment, including safety gloves and glasses.

Visual Inspection:

Visually inspect the bus duct, connections, and termination points for any visible damage or loose connections. Repair any visible issues before proceeding.

Prepare the Test Setup:

• Connect the Kelvin test leads to the digital multimeter.
• Set the multimeter to the low-resistance measurement mode (typically in the mΩ range).
• Zero the test leads to compensate for lead resistance. This ensures accurate measurements.

Measurement Points:

• Identify the specific connection points within the bus duct that you want to test. Typically, these are the main busbar joints, branch connections, and any critical connections.
• Clean the contact surfaces of the connections using a wire brush or contact cleaner to ensure a clean and low-resistance contact.

Perform the Resistance Measurement:

• Connect the Kelvin test leads to the contact points under the test. Ensure a secure and stable connection.
• Record the resistance reading displayed on the digital multimeter. This reading represents the contact resistance between the two points.
• For accurate results, ensure there is no external current flow or magnetic fields affecting the measurement.

Repeat for Multiple Points:

Repeat the resistance measurement process for all the critical contact points within the bus duct.

Comparison and Analysis:

• Compare the measured resistance values with the manufacturer's specifications or industry standards. Generally, lower resistance values indicate better contact quality.
• Identify any connections with high resistance values, as they may indicate loose or deteriorating connections that require immediate attention.

Documentation:

• Document the test results, including the location and resistance values of each tested connection.
• Highlight any connections that fall outside acceptable limits.

Maintenance and Remediation:

• Based on the test results, schedule maintenance, and remediation activities for connections that do not meet the required standards.
• Retest repaired or replaced connections to ensure they now meet the acceptable resistance levels.

Re-Energize the System:

Once all necessary repairs and maintenance are completed, and you have verified that the contact resistance is within acceptable limits, you can safely re-energize the bus duct.

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