1. Level 1 Diploma in Electrical Installation © 2013 City and Guilds of London Institute. All rights reserved. 1 of 11 PowerPoint presentation Outcome 4: Be able to use technical information Unit 107: Electrical science and technology

2. Level 1 Diploma in Electrical Installation © 2013 City and Guilds of London Institute. All rights reserved. 2 of 11 Drawing types (4.1) All electricians and engineers need drawings and diagrams to work from: Circuit drawings –Shows how circuit operates –Good for finding faults Wiring diagram –How system put together –Location/routing/length of runs Architect (layout) drawing –Location of systems –Scale Other drawings used: –Schematic/block diagrams –As fitted drawings

3. Level 1 Diploma in Electrical Installation © 2013 City and Guilds of London Institute. All rights reserved. 3 of 11 Drawing types (4.1) Typical circuit diagram

4. Level 1 Diploma in Electrical Installation © 2013 City and Guilds of London Institute. All rights reserved. 4 of 11 Drawing types (4.1) Typical wiring diagram

5. Level 1 Diploma in Electrical Installation © 2013 City and Guilds of London Institute. All rights reserved. 5 of 11 Drawing types (4.1) Typical architect (layout) drawing

6. Level 1 Diploma in Electrical Installation © 2013 City and Guilds of London Institute. All rights reserved. 6 of 11 Drawing types (4.1) Other drawings: block or schematic diagram

7. Level 1 Diploma in Electrical Installation © 2013 City and Guilds of London Institute. All rights reserved. 7 of 11 Common electrical symbols (4.2) To understand drawings the following symbols must be known:

8. Level 1 Diploma in Electrical Installation © 2013 City and Guilds of London Institute. All rights reserved. 8 of 11 Calculations with scales (4.3) Installing an electrical system from a drawing will mean understanding how to work with scales – failure to read scales could be expensive!

9. Level 1 Diploma in Electrical Installation © 2013 City and Guilds of London Institute. All rights reserved. 9 of 11 Working with scales (4.3) Most drawings are produced at a scale that make the information easy to read and follow – if a diagram of a house were life-size it would be very difficult to use! Represent a real-life measurement by a smaller number Scales are ratios Left side is the ‘paper’ Right side is the ‘reality’ For example:1 : 50 1mm on the paper : 50mm in reality

10. Level 1 Diploma in Electrical Installation © 2013 City and Guilds of London Institute. All rights reserved. 10 of 11 Working with scales (4.3) Once you have the ratio, all you need to do is multiply or divide depending on which way you are going and what you are trying to find: the size on the paper or the size in reality! Example: A light is shown on a diagram 10mm from one wall and the scale on the diagram says it is 1:50 1mm on the paper means 50mm in reality (1:50 scale) We need to find the real measurement so, 10 x 50 = 500mm or 0.5m The light needs to be fixed 0.5m from the wall

11. Level 1 Diploma in Electrical Installation © 2013 City and Guilds of London Institute. All rights reserved. 11 of 11 Any questions?