HomeMy WebLinkAboutLoads Calcs.pdf
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Solar Installation Information
Vendor: Active Energies Solar LLC
PO Box 7627
Avon, CO 81620
(970-306-4233/info@activeenergies.com)
Site: Corrigan Residence
2722 Cortina Lane
Vail, CO 81657
All AC wiring to be completed by a Colorado licensed master electrician
All DC wiring to be overseen by NABCEP certified installer
Minimum Designed Temperature: -40°F
Maximum Ambient Design Temperature: 140°F
Panel Arrangement: Panel Arrangement: 5 rows of 8 panels between the snow fences, oriented in the portrait
position, mounted flush on the south facing metal roof
A: PV AC Disconnect
B: Meter
A
B
PV Panels: 40 Phono PS250P-20/U
Inverters: 40 Enphase M-215 240v
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Calculations
10.0kW System Size (STC)
40 Phono Solar PS250P-20/U solar panels @ 250 watts
40 Enphase M-215 240 micro-inverters –3 branch of 8/16/16 units each
Fixed array tilt angle: 11.77º
Array azimuth: 180° (where 180º is south)
Estimated annual power production: 13,603kWh
Maximum PV System Voltage: 690.7
Voc= 37.8V/module
37.8V x 1 module = 37.8V
Temperature correction factor 690.7(A)
STC = 25°C, Temperature Coefficient (Voc) = -0.31%/°K
(298°K- 233°k) = 65°K
37.8V + (-65°K x (-0.31%/°K x 37.8V) x 1 module) = 45.4V
Temperature correction factor Table 690.7
For -40ºF use 1.25
37.8V x 1.25 = 47.3V
Maximum PV Source Circuit (String) Current: 690.8 (A)(1)
Isc = 8.7A
8.7A x 1.25 = 10.9A
Maximum PV Output Circuit (Array) Current: 690.8 (A)(2)
10.9A x 1 strings = 10.9A
Inverter Output Circuit Current: 690.8 (A)(3)
.9A @ 240V
John Wiles, “Photovoltaic Power Systems and the National Electrical Code: Suggested
Practices”, 2005, pp. E1-E25.
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Conductor Sizing
Pass Thru Box on Roof to PV Sub-Panel (for a 16 panel circuit):
Nameplate maximum continuous output current:
.9A
Maximum Output Power 215 Watts AC
215W ÷ 240 V = .9A
.9A x 16 inverters = 14.4A per branch
14.4A x 125% = 18A
#10 NM-B Table 310.16
35A (75ºC column, see note 240.4(D))
Conduit fill adjustment Table 310.15 (B)(2)(a)
No Conduit Fill Adjustment
Temperature correction factor Table 310.16
No Temperature Correction
PV Sub-Panel to Disconnect to Service Panel (for a 40 panels):
.9A x 40 inverters = 36A per branch
36A x 125% = 45A
#8 NM-B Table 310.16
50A (75ºC column)
Conduit fill adjustment Table 310.15 (B)(2)(a)
No Conduit Fill Adjustment
Temperature correction factor Table 310.16
No Temperature Correction
Overcurrent Protection
20A two pole per Enphase circuit Per Manufacturer Specification
50A two pole backfeed breaker