2391 Inspection & Testing Pro

Three new on-site calculators, built from the IET On-Site Guide. • R1+R2 — predict the continuity reading for a circuit before you measure it. Pick the line and cpc sizes and the run length; you get the value at 20 °C and at operating temperature. • Zs from Components — Ze + (R1+R2), checked against the tabulated limit. Tell it whether your (R1+R2) is a 20 °C or an operating-temperature figure and it applies the right limit, so the temperature correction is never done twice. • Prospective Fault Current — Ipf from either loop, reporting the greater of PEFC and PSCC, which is the figure the certificate asks for. QUICK REFERENCE — 11 NEW CARDS • Maximum measured Zs for circuit-breakers, straight from Appendix B • (R1+R2) per metre and the temperature multipliers • A new Wiring identification & colours section — protective, AC and DC conductor marking • What the RCD test button does not prove, and when to test L2 and L3 • The six BS 7671 model forms and what a Schedule of Test Results must record PLEASE NOTE Ring Final has moved into the subscription tier. The free calculators are now Adiabatic, Max Zs and Prospective Fault Current.