A detailed document containing every formula used in Electrical Installation Level 2, detailing what each formula letter means and it's SI unit of measure.
 
Also included is a detailed wiring diagram, that which is used in the exam questions. Showing the earthering arrangments for a TT, TNC and TNCS earthing system.
 
This is a useful, and powerful revision aid that you can read anytime. It has also been custom made to fit directly into your On Site Guide, so you can always have it with you whilst in class. 
 
These formulae pages are available for free to all members who hold an annual subscription.