Tap boxes are an enclosed junction box that connects incoming and outgoing cables to a mechanical lug to ensure a strong connection between power sources. Tap. Enclosed tap boxes are great product to make splices in an enclosed, secure electrical junction box. These are available in carbon steel or stainless steel upon request. Starting from the main distribution, the TAP box supplies power to your individual tunnel applications, such as the lighting and evacuation. Square D Meter Centres provide a compact and versatile metering and distribution centre for today's residential, commercial, and industrial markets.