How to Terminate a Cable Lug onto an Earth Bar

Terminating a cable lug onto an earth bar can be a source of confusion within the industry. For example, it is often unclear whether the cable lug should be bolted face down directly onto the copper bar or if it should be positioned ‘floating’ between the nuts.

 

This article, based on guidance from A.N. Wallis, aims to provide clear instructions for proper cable lug termination on an earth bar, eliminating common errors that occur during installation.

Understanding Earth Bar Termination Components

Before discussing the correct installation process, it’s crucial to become familiar with the termination components of the earth bar.

Each standard termination point in a typical AN Wallis setup includes the following components:

  • 1 No. x M10x35 Phosphor Bronze Hex Head Set (7)
  • 1 No. x M10 Phosphor Bronze Flat Washer (4)
  • 1 No. x M10 Phosphor Bronze Spring Washer (8)
  • 2 No. x M10 Phosphor Bronze Full Nuts (5)

When assembled, these components are arranged on the earth bar in the following order:

Hex Head Set → Flat Washer → Nut → Spring Washer → Nut

Recommended Method for Terminating
a Cable Lug onto an Earth Bar

The suggested method for terminating a cable lug onto an earth bar is to ‘fix’ the flat side of the cable lug directly to the copper bar. This approach ensures full contact between the connecting cable and the earth bar, preventing any reduction in cross-sectional area.


Based on the components provided by AN Wallis, we recommend the following sequence for securing the cable lug to the earth bar:

  1. Lug over the Hex Head Set (in direct contact with the Copper Bar)
  2. Flat Washer
  3. Spring Washer
  4. Nut
  5. Nut

    Under typical conditions, using a spring washer and one nut should be sufficient for securing the cable lug. However, AN Wallis goes above and beyond by supplying two nuts. The second nut acts as a lock against the first nut, making the installation even more secure and safe.

Incorrect Method for Terminating a Cable Lug onto an Earth Bar

Sometimes, people mistakenly believe that the two nuts supplied should be used to ‘sandwich’ the lug between them, with the lug ‘sitting’ on one nut and tightened by the other. This method is incorrect and not recommended, as it does not allow full contact between the connecting cable and the earth bar, resulting in a reduced cross-sectional area.

 

Two possible reasons for using this incorrect method are a lack of knowledge or training in proper installation procedures and the ‘laziness’ of the installation contractor, who might want to save time and effort by not fully disassembling the termination components to attach the lug and reassemble correctly. While this may save some installation time, it is incorrect and, more importantly, unsafe.

 

In conclusion, the recommended method for terminating a cable lug onto an earth bar is to ‘fix’ the flat side of the cable lug directly to the copper bar, ensuring direct contact between the cable lug and the copper bar. This approach allows for full contact between the connecting cable and the earth bar, preventing any reduction in cross-sectional area.

A.N. Wallis Earthing Solutions and Al Sabah’s Expertise

AN Wallis designs, manufactures, and supplies thousands of earth bars every year, making it one of their core product ranges. Al Sabah, as a partner of AN Wallis in the Kuwait region, benefits from their extensive experience and expertise in earth bars. This places Al Sabah in an ideal position to address questions or concerns related to earthing protection and earth bars. Together, they ensure the production of high-quality, affordable earth bars that are designed and tested according to relevant standards – manufactured from hard-drawn copper bar per BS EN 13601 and tested to BS EN 62561-1 Class H.

Need Assistance? Contact Al Sabah Today!

Al Sabah is here to help with any questions you may have about our product range or any specific items required for your project. Don’t hesitate to reach out to our expert team at +965-2240-9913 for personalized support and guidance.