Description

The Extension Box Metal Hollow Deep Square 4 in. × 4 in. × 1½ inch is a robust, pre‑galvanised steel extension ring designed to increase the depth and wiring capacity of standard 4″ square electrical boxes. With a generous 21 cu in interior volume and 1½″ added depth, it accommodates additional conductors, connectors, and devices while maintaining a compact footprint. Its durable steel construction CSA compliance make it ideal for rough‑in applications in residential, commercial, and light‑industrial settings, ensuring electrical systems remain code‑compliant, organised and safe.