Maximum Demand Calculation Jun 2026

Start by auditing your last 12 utility bills. Identify the maximum demand recorded. Then walk through your facility with a power logger. You will likely find that you are paying for capacity you do not need – or dangerously close to tripping your main breaker.

A facility with a real demand of 400 kW at PF=0.7 has an MD of . Correcting to PF=0.95 reduces MD to 421 kVA . At $10/kVA, that's a monthly saving of $1,500.

At its heart, Maximum Demand (MD) is the greatest average load (typically in kW or kVA) that an electrical installation draws during a specific time interval over a billing period. It's not the absolute highest instantaneous current, but the highest sustained demand, usually averaged over a 15, 30, or 60-minute window.

Assume measured PF = 0.85 [ MD_kVA = \frac109.150.85 = 128.4 \text kVA ] maximum demand calculation

Scenario:

Ensures cables and switchgear are sized correctly to prevent overheating or fires.

To accurately perform a maximum demand calculation, you must understand several foundational power engineering concepts: Start by auditing your last 12 utility bills

Diversity Factor=∑(Individual Max Demands)System Max DemandDiversity Factor equals the fraction with numerator sum of open paren Individual Max Demands close paren and denominator System Max Demand end-fraction Coincidence Factor ( The reciprocal of the diversity factor (

While specific formulas vary by region, the logic generally follows these steps:

Isockets=10 A+15 A=25 Acap I sub sockets end-sub equals 10 A plus 15 A equals 25 A 3. Calculate Cooktop Group to full current, then apply the diversity factor: You will likely find that you are paying

Utilizes standard and optional calculation methods outlined in NEC Article 220. It employs fixed volt-ampere (VA) allocations per square foot for general lighting and specific demand reduction tables for household electric ranges and clothes dryers.

To better understand how diversity factors prevent over-scoping, consider how power fluctuates over a