Even experienced engineers fall into these traps:

Pro Tip: Do not trust one day of data. A single anomaly (testing a backup generator, a heatwave) could set an unrealistic MD.

1. Cost Reduction (The "Diversity" Factor) The single greatest advantage of a proper MD calculation is capital expenditure (CAPEX) reduction. By applying diversity factors (e.g., not every power point will draw 10A at 5 PM), you can size a main switch for 400A instead of 800A. In one commercial tower review, an accurate MD saved $47,000 in cable and transformer costs.

2. Preventing Nuisance Tripping When MD is calculated accurately, the main circuit breaker holds during peak hours. Conversely, an overestimated MD (sizing too large) is dangerous because a fault might not trip the breaker quickly enough. A good calculation balances thermal limits with fault tolerance.

3. Utility Bill Management Most commercial tariffs include a kVA demand charge (e.g., $15 per kVA per month). An accurate MD calculation allows you to negotiate a lower contracted capacity with the utility. Overestimating by 200 kVA could cost you $36,000 annually in wasted demand charges.

Demand charges typically constitute 30–60% of a commercial/industrial electricity bill. For example: