Exam Question

### (a) Precautions for Portable Electrical Equipment in Confined Spaces (10 Marks)
Safe operation of portable electrical tools and lighting within a confined space, such as a boiler, is governed by a multi-layered safety approach designed to mitigate the primary risks of electric shock, fire, and explosion. The metallic, damp, and enclosed nature of such spaces significantly elevates these risks.
**1. Electrical Shock Prevention (Primary Hazard)**
* **Use of Reduced Voltage (SELV):** The most critical safety measure is the use of a Separated Extra-Low Voltage (SELV) supply. This is achieved by using a portable step-down transformer, typically with a primary voltage of 230V or 110V and a secondary output of **24V AC**.