City & Guilds 2391-51 case studies
City & Guilds 2391-51 · Put your knowledge to work in context.
City & Guilds 2391-51 is the Level 3 Award in Periodic Inspection, Testing and Certification of Electrical Installations. It is a competence-style qualification for practising electricians who already install and maintain circuits and now need to inspect, test, certify and condition-report existing installations rather than newly commissioned ones. The City & Guilds 2391-51 case studies are 5 cases and about 4,097 words.
1Agreeing the extent of a periodic report in an occupied care home
You are engaged to produce an EICR for a 42-bed residential care home built in 1998: one origin (TN-C-S, 100 A), a 12-way three-phase main board, four single-phase sub-boards and 96 final circuits. The previous report, issued in 2016, records 'satisfactory' with no schedules or test results attached.
751 words, about 4 min2Interpreting ring final circuit results on a periodic inspection
On a periodic inspection of a 1980s three-bed semi you isolate the ground-floor ring final: 32 A Type B BS EN 60898 MCB, 2.5 mm² line and neutral, 1.5 mm² cpc, protected by a 30 mA RCBO. End-to-end readings are r1 = 0.40 Ω, rn = 0.41 Ω, r2 = 0.68 Ω.
748 words, about 4 min3RCD behaviour and loop impedance on a village hall kitchen
A 1970s village hall kitchen is fed from a 32 A Type B MCB (2.5/1.5 mm² T&E); the whole installation sits behind a 30 mA Type AC RCD at the origin, shared with the lighting and an outside socket. Catering equipment includes a commercial dishwasher with a variable-speed drive, a 3 kW water boiler and a hand dryer.
871 words, about 4 min4Classification codes on an office EICR
An EICR of a two-storey office: TN-S, Ze 0.21 Ω, 100 A main switch, one main board in a locked riser and seven sub-boards. You record the following.
852 words, about 4 min5Safe isolation on an installation with PV and battery storage
The property is a 2019 four-bed detached house on TN-C-S with a 4 kWp roof array, a 3.6 kW hybrid inverter and a 5 kWh battery in the integral garage, plus a 7.4 kW EV charge point on the outside wall. The consumer unit is in the hall cupboard; the inverter has an AC isolator beside the consumer unit and DC isolators next to the inverter.
875 words, about 4 min