Electrical Load Calculation Findings - 47B American Spirit

Date: July 29, 2025 | Time: 06:54 PM MDT

Summary

This report details the electrical load analysis for a 6,525 sq ft home with a ~400A service (96,000 VA capacity; safe continuous ~80% = 320A/76,800 VA). New additions (3 × 1 HP hydraulic motors: 5,760 VA; electric floor heat: 5,760 VA; garage-style heater: 5,760 VA; total 17,280 VA) are assigned to Panel B. Calculations use NEC 220.82 optional method.

Demanded Load Table (NEC-Calculated Service/Feeder Requirement)

Panel/Feeder Connected Load (VA) Demanded Load Breakdown Demanded Load (VA) Demanded Amps @ 240V % of Safe Continuous Capacity (160A/Feeder) Notes
Panel B (200A Feeder) 68,960 (Lighting: 15,000; Small/Laundry: 4,500; Fixed: 49,460 incl. new additions) First 10k @100%: 10,000; Remainder @40%: 23,584; +HVAC @100%: 2,160 35,744 149 93% Marginal; code-compliant but limited growth room.
Panels A+C (200A Feeder) 82,233 (Lighting: 4,575; Small/Laundry: 9,000; Fixed: 68,658) First 10k @100%: 10,000; Remainder @40%: 28,893 38,893 162 101% Overloaded; exceeds 80% rule—recommend balancing or upgrade.
Whole Home (400A Service) 151,193 First 10k @100%: 10,000; Remainder @40%: 56,477; +HVAC @100%: 2,160 68,637 286 89% (of 320A safe) Marginal overall; sufficient per code but monitor peaks.

Continuous Load Table (Loads >3 Hours)

Panel/Feeder Key Continuous Loads Estimated Continuous VA Continuous Amps @ 240V % of Feeder Capacity (200A) Notes
Panel B Hot tub (11,520 VA); Lifebreath HVAC (2,160 VA); New floor heat (5,760 VA); New garage heater (5,760 VA) ~25,200 (sum; assumes simultaneous) 105 53% Safe; but if all run >3h (e.g., winter), approaches 80% limit—use timers.
Panels A+C Steam shower (10,080 VA; if long use); Heat tape (4,800 VA); Dehumidifiers (1,000 VA) ~15,880 (sum) 66 33% Safe; lower due to intermittent nature of most A+C loads.
Whole Home All above + minor others (e.g., AV racks if always-on ~8,400 VA) ~49,480 206 52% (of 400A) Safe overall; focus on balancing to prevent feeder overload.

Possible Peak Load Table (Worst-Case Simultaneous Draw)

Panel/Feeder Assumed Peak Scenario Peak Load Breakdown Peak VA Estimate Peak Amps @ 240V Risk Level Notes
Panel B Winter: Hot tub + HVAC + new heaters/floor heat + elevator/motors + garage doors + laundry + lighting/receptacles Hot tub/HVAC/heat additions: ~25,200; Motors/elevator: ~11,760; Other fixed/small: ~10,500; Lighting: 15,000 ~62,460 (~90% of connected) 260 High (130% of 200A—potential trip) Over feeder rating if all simultaneous; mitigate with load shedding (e.g., smart breakers).
Panels A+C Party: Full kitchen (range/oven/dishwashers/fridges ~25,000) + steam shower + heat tape + AV/shades + laundry + lighting Kitchen/appliances: ~35,000; Shower/heat tape: ~15,000; AV/other fixed: ~10,000; Small/laundry: 9,000; Lighting: 4,575 ~73,575 (~90% of connected) 307 Very High (153% of 200A—likely trip) Already risky; peaks could exceed even without additions—urgent balancing needed.
Whole Home Combined peaks (e.g., full house use) Sum of above ~136,035 567 High (141% of 400A—service overload) Unlikely all at once, but highlights need for monitoring (e.g., energy management system).