Guidance Note 6: Protection Against Overcurrent is a key guide to this important area of BS 7671. It is intended for all involved with specifying, designing, installing or verifying electrical installations and has been fully updated to BS 7671:2018.

• Chapter 1: The regulations concerning protection against overcurrent
• Chapter 2: Protection against overload
• Chapter 3: Protection against fault current
• Chapter 4: Determination of fault current
• Chapter 5: Equations for the calculation of short-circuit current
• Chapter 6: Equations for the calculation of earth fault current
• Chapter 7: Selection of conductor size
• Appendix A: Calculation of reactance
• Appendix B: Calculation of k for other temperatures