2008 commercial service sizing 2008
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Copyright 1999-2006 Dan Dudley
Commercial Service Sizing
Commercial Service Sizing
Calculations
Commercial Service Sizing
Copyright 1999-2007 Dan Dudley
Standard Commercial CalculationsStandard Commercial Calculations
• Six loads are considered:– Lighting Loads– Receptacle Loads– Special Appliance Loads– Heating or A/C Loads– Motor Loads– Largest Motor Load
Commercial Service Sizing
Copyright 1999-2007 Dan Dudley
• Lighting Loads considered:– General Lighting Loads– Show Window Loads– Lighting Track Loads– Outside Lighting Loads– Sign Lighting Loads
Standard Commercial CalculationsStandard Commercial Calculations
Copyright 1999-2006 Dan Dudley
Commercial Service Sizing
Given:
50’ X 60’ Store (3000 Sq Ft)
30’ Show window lighting
Total of 80 duplex receptacles
240/120 V, 1 phase, 3 wire service
Actual connected load of 8500 VA
Commercial Service SizingCommercial Service Sizing
Copyright 1999-2006 Dan Dudley
Commercial Service Sizing
Solution: Calculation Code Citation
Continuos Loads:
3000 Sq Ft X 3 VA X 125% 11,250 VA T220.12 / 215.2(a)(1)
Sign Lighting 1200 va X 125% 1,500 VA 600.5
Show Window 30’ X 200 VA X 125% 7,500 VA 220.14(G)(2)
20,250 VA
Other Lighting Loads
Non-Continuos Loads:
Receptacles 80 X 180 VA 14,400 VA 220.14(j)
first 10,000 Va @ 100% 10,000 VA T220.44
Remaining 4,400 Va @ 50% 2,200 VA
Existing load 8,500 VA
TOTAL VA 40,950 VA
220.14(G)(1) and 210.62 state that the PER RECEPTACLES LOAD is calculated at 180VA per receptacle and there must be at least one (1) per 12 linear feet.
Copyright 1999-2006 Dan Dudley
Commercial Service Sizing
TOTAL DEMAND 40,950 VA
Line = 40,950 VA / 240 V = 170.625 Amps
Neutral = 170.625 Amps = 170.625 Amps
Service Feeder = # 2/0 THW, THHN T310.16
Service Neutral = # 2/0 THW, THHN T310.16
Grounding Electrode Conductor = # 6 T250.66
Equipment Grounding Conductor = # 6 T250.122
NOTE** Article 110.14(c) 1 & 2 still applies and you select the conductor size according to the AMPACITY. (75°C rating)
Neutral note* 220.621(B)(2) Allows 70% neutral after first 200AMPS is taken at 100%.
Copyright 1999-2006 Dan Dudley
Commercial Service Sizing
Receptacle Load unknown
T.220.12 note b