Maximum Demand Table C1 May 2026

In the field of electrical engineering, safety and economy often exist in a state of tension. Designing a system with excessive capacity guarantees safety but wastes resources, while an under-sized system is economical but dangerous. The tool that resolves this tension for residential and similar installations is the Maximum Demand Table C1 . Far from being a mere reference page in a wiring standard, Table C1 is a critical instrument that allows electricians and engineers to calculate the expected total current draw of an installation, ensuring that main switches, cables, and supply equipment are neither dangerously overworked nor wastefully oversized.

Table C1 provides —statistically derived multipliers that reduce the theoretical full load to a realistic maximum demand. It acknowledges that not all loads operate simultaneously, and those that do may not do so at full capacity. By applying the table, a designer converts a mathematically impossible "worst-case" total into an economically and practically realistic figure. maximum demand table c1

The impact of Table C1 is felt directly in the cost and feasibility of an installation. Consider a small retail shop with 30 double socket outlets. The raw connected load might be 30 × 240W (a conservative appliance rating) = 7.2kW per phase. Without diversity, this would demand a 30A supply per phase. However, Table C1 typically allows a diversity factor of 0.5 for general socket outlets in commercial settings, dropping the demand to 3.6kW—requiring only a 16A supply. In the field of electrical engineering, safety and