Technical Guides
Our technical guides are designed to help electricians, contractors, and specifiers select, install, and maintain Terelec products correctly and safely. These guides supplement the installation instructions supplied with each product.
Consumer Unit Selection Guide
Choosing the right consumer unit depends on the number of circuits, the type of incomer (main switch, RCD, or dual RCD), and whether surge protection is required under the latest edition of BS 7671. This guide walks you through the selection process and explains the differences between our main switch, RCD incomer, dual RCD, and SPD-integrated consumer unit ranges.
EV Charger Installation Guide
A practical guide covering the electrical requirements for installing a dedicated EV charger circuit. Topics include supply assessment, cable sizing, protective device selection (Type B RCD, RCBO, SPD), earthing arrangements, and compliance with BS 7671 Regulation 722 and the IET Code of Practice for Electric Vehicle Charging Equipment Installation.
MCB Selection — Type B vs Type C
Understanding when to use Type B or Type C miniature circuit breakers. This guide explains the tripping characteristics, typical applications (lighting, sockets, motors, commercial equipment), and how to select the correct MCB type and rating for the circuit.
Surge Protection — Amendment 2 Requirements
Amendment 2 to BS 7671 introduced new requirements for SPD installation in many domestic and commercial settings. This guide explains when an SPD is required, how to select the correct type and rating, and where to install it within the distribution board.
Type B RCD Requirements for EV Charging
EV chargers can produce DC fault currents that standard Type A RCDs cannot detect. This guide explains why Type B (or Type A with DC 6mA detection) RCDs are required for EV installations under BS 7671 Regulation 722.531.3.101, and how to correctly specify the protective device for your installation.
Need Help?
If you have a technical question about any Terelec product or need guidance on product selection for a specific installation, our technical support team is happy to help.
Phone: +44 7777 175890
Email: info@terelec.co.uk
