A common cause of power quality issues in underground systems is the improper torquing of underground separable connectors. During the installation of these products, achieving proper connections is one of the most important yet overlooked step in the installation process.
Importance of Proper Torque
Underground separable connectors are comprised of soft metals, such as copper and aluminum, and are usually rated for 200A, 600A, or 900A applications. It’s crucial to achieve the proper torque so that the products can carry the amount of current they are rated for. A loose connection will create heat while over-torquing the connection can damage the threads. Both of these conditions can contribute to a power outage.
Proper Tools and Torque Requirements
Depending on the type of product, loadbreak or deadbreak, the torque values can range from 110-inch pounds to 60-ft pounds. Bushing Inserts and Elbow Tap Plugs (ETPs) have similar appearances, but significantly different torque requirements. Bushing Inserts are properly torqued at 15 ft pounds while ETPs are torqued at 50-60 ft pounds.
There are torque tools available to accommodate both ranges. Be sure to use the correct tools for the correct part. Torque tools can get out of calibration, so check them yearly to ensure proper torque values are being achieved. Read the instruction sheets provided with each Cable Accessories product for the correct torque values and required tools. Some torque values differ according to other manufactures, always read the instruction sheet provided.
Below are common cable accessories and the torque values for them.
- Loadbreak Elbow Probe - 110 inch lbs
- Bushing Insert - 15 ft lbs
- Elbow Tap Plug - 50-60 ft lbs
- Basic Insulating Plug - 50-60 ft lbs
- Loadbreak Reducing Tap Plug - 20-25 ft lbs (after the shear pin has been sheared connecting the LRTP to the threaded connector)
- Connecting Plug - 50-60 ft lbs (torque both sides to 50-60 ft lbs)