In multi-unit developments, communal loads (e.g., car park lighting, lifts) are calculated separately and added to the unit totals using specific factors found in later sections of the table or by referring to Table C2 for non-domestic equipment like lift motors.

Maximum demand is defined as the greatest average load (typically measured in amperes or kilovolt-amperes) likely to be drawn by an electrical installation under normal operating conditions over a specified interval. It is not a simple sum of every circuit breaker’s rating; if one added every light, power point, and appliance rating in a house, the total would be far higher than any actual real-world draw. This is where Table C1 comes into play.

When you are designing an electrical installation, you follow this general workflow:

3A for the first 20 points + 2A for each additional 20 points. Socket-outlets (≤ 10A)

Here is a breakdown of what Table C1 is and how it is used in conjunction with Maximum Demand calculations.