HOLT Electricians Practice Exam

A boiler employing resistance-type immersion heating elements rated above 120 amperes must subdivide the heating elements into loads not exceeding how many amperes?

1. 80 amperes

2. 100 amperes

3. 120 amperes

4. 140 amperes

The correct answer is: 120 amperes

In electrical installations, particularly those involving heating elements, there are specific guidelines to ensure safety and efficiency. For boilers that utilize resistance-type immersion heating elements rated above 120 amperes, it is crucial to subdivide these loads in accordance with established electrical safety standards. The requirement to subdivide into loads not exceeding 120 amperes arises from the need to manage the thermal and electrical characteristics of the heating elements effectively. When heating elements are rated above this threshold, allowing them to operate at the full capacity without subdivision can lead to excessive heat and potential hazards. The standard of limiting the loads to 120 amperes helps in distributing the electrical load safely across multiple circuits, reducing the risk of overheating, and ensures compliance with wiring regulations to prevent any fire hazards or equipment damage. This standard aligns with best practices in electrical safety, ensuring that the system remains reliable and safe under normal operating conditions, while also facilitating maintenance or replacement procedures in the future without significant risk of failure. Overall, ensuring that no single load exceeds this rating enhances the longevity and safety of the entire heating system.