Why is the "CAT" rating necessary when purchasing a meter?

The "CAT" rating, or Category rating, is a critical factor when purchasing a meter as it is specifically designed to confirm that the meter is user safe for various applications. This rating indicates the meter's ability to withstand high voltage transients typically encountered in electrical systems, providing assurance that it can handle the specific environment for which it's intended. For instance, CAT ratings range from CAT I to CAT IV, with each category designed for different levels of electrical risk. A meter rated for a higher category will provide better protection against electrical surges and can be safely used in environments with higher voltage and energy levels, thus ensuring user safety during testing or troubleshooting activities.

The other options do not directly relate to the core purpose of the CAT rating. A meter’s battery life is not influenced by the CAT rating, nor does the rating indicate compatibility with previous models or assess the brand's overall quality. Instead, it is specifically focused on safety and appropriate usage in various electrical settings.