Why is it important to test a line on a known energized source?

Testing a line on a known energized source is crucial for ensuring the accuracy and functionality of the testing device being used. By connecting the tester to a confirmed live source, linemen can verify that their equipment is working as intended, which is vital for safe operations. If the tester is not functioning properly, it may provide false readings, leading to potentially dangerous situations where workers might assume that a line is de-energized when it is not.

While validating grounding methods, confirming line safety, and checking voltage levels are all important aspects of line work, the primary purpose of testing against a known energized source is to establish that the testing equipment itself is reliable. This step ensures that all subsequent readings or evaluations about line conditions will be based on accurate and trustworthy information, thereby maintaining safety protocols and operational efficiency.