FeederSpec
NEC feeder/branch sizing + service load calc. For specification & estimating — verify against project fault current and terminations.
Feeder / Branch Sizing
Design current188 A
OCPD (breaker/fuse)200 A
Conductor3/0 AWG Cu
Conductor ampacity200 A
Voltage drop0.62% (3 V)
Wire (Cerrowire)THHN/THWN-2
Cerrowire THHN/THWN-2 Building Wire — Default feeder/branch conductor pulled in conduit (dry or wet, dual-rated).
- Continuous load: OCPD & conductor sized at 125% (NEC 210.20/215.2/215.3).
Service / Feeder Load Calc (NEC 220)
General lighting (20000 sq ft × 3.5 VA/sq ft)70,000 VA
Receptacle load (220.44)30,000 VA
HVAC80,000 VA
Motors25,000 VA
Largest motor +25% (430.24)6,250 VA
Total connected211,250 VA
Demand current254 A
Service size300 A
- Largest-motor adder approximated as 25% of total motor VA — refine with the actual largest motor.
- Demand factors not applied — this is a connected-load calc. Apply Article 220 Part III/IV demand factors where permitted.