Progress Solar/Wind SLT 700 Series Operator's Manual page 130

APPENDIX A - Wire Sizing
Minimum Wire Sizing
Wire sizing requirements are based on the ampacity (or current carrying capacity) of conductors. The
NEC includes Ampacity Tables which are used to determine the ampacity for a given wire size as
indicated in Section 310.15.
TriStar MPPT power terminals are rated for 75ºC. When wires with a 90°C temperature rating are
used with terminals that have a 75°C temperature rating, wire ampacity at 75°C must be used.
Wire ampacity requirements for the battery and PV array circuits are as follows:
Controller battery wire ampacity must be greater than or equal to 125% of maximum continuous
current (battery current rating of the controller)
PV array wire ampacity must meet both of the following requirements:
Must be greater than or equal to 156% of PV Array Isc without correction and adjustment factors
Must be greater than or equal to 125% of PV Array Isc with correction and adjustment factors
Correction and adjustment factors may also be required to account for the following:
• maximum ambient temperature
• temperatures at different parts of the circuit (rooftops or engine rooms for example)
• wire terminal temperature ratings
• multi conductor cables
• conduit fill and other factors
70 Specifications
Minimum Battery Wire Sizes - 75°C or 90°C Rated Stranded Copper
Wire Size in a raceway, cable,
or earth 1
MODEL
@30ºC 30º-45ºC
TS-MPPT-30 #8 AWG #8 AWG
TS-MPPT-45 #6 AWG #4 AWG > 40°C
#3 AWG > 40°C
TS-MPPT-60/M #4 AWG
Per NEC 2021 [see NEC Table 310.15(b)(16)], ampacity for not more than three current-carrying
1
conductors in a raceway, cable, or earth (buried)
Per NEC 2021 [see NEC Table 310.15(b)(17)], ampacity for conductors in free air
2
Estimated. See local code requirements for metric cable sizing
3
Table A-1. Minimum Battery Stranded Wire Sizes for 75°C or 90ºC Rated Copper
Celsius to Fahrenheit Conversions
ºCelsius
Table A-2. Celsius to Fahrenheit Conversions
TriStar MPPT Operator's Manual
Wire Size in free air 2
@30ºC 30º-45ºC
#10 AWG #10 AWG
#8 AWG #8 AWG
#6 AWG #6 AWG
ºFahrenheit
30 86
35 95
40 104
45 113
Metric
Wire Size 3
(mm 2 )
6 - 10
10 - 18
16 - 25
71