hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
I have SE 14.4k inverter 208V three phase output. On the DC inverter side I have EMT condit with 6 #10 Thwn-2 + #8 Gnd from inverter which is inside the building to outside to roof. On the roof under solar panels I have junction box which transtion cable to 6 #10 PV wire + #8 Gnd which go to solar panel 3 strings without conduit.
Now when I do my calculation for cable sizing Thwn-2 copper is 90 degree C only column ampacity table ampacity of 40A.
My more than 3 current carrying derating is 0.8
My roof temp correction factor is 0.76
My optimizer worst case Isc is 18A.
40x0.76x0.8 = 24
18x1.25 = 22
24>22.
My questions are following is in regarding 110.14(C) temprature rating:
1. Do my terminals, device have to be rated 90C?
2. If terminals or device are 75C then 40A would not be the ampacity and 75C would apply? If yes then Thwn-2 is not in 75C. What would be new amapcitty be?
3. Is their such a thing inverter rated 90C or inverter terminal rated 90C?
4. How does 110.14(C) apply to inverter terminals or inverter temp rating?
I appreciate your input. Not trolling but trying to clear things up please if possible forgive my ignorance.
Sent from my SM-G935U using Tapatalk
Now when I do my calculation for cable sizing Thwn-2 copper is 90 degree C only column ampacity table ampacity of 40A.
My more than 3 current carrying derating is 0.8
My roof temp correction factor is 0.76
My optimizer worst case Isc is 18A.
40x0.76x0.8 = 24
18x1.25 = 22
24>22.
My questions are following is in regarding 110.14(C) temprature rating:
1. Do my terminals, device have to be rated 90C?
2. If terminals or device are 75C then 40A would not be the ampacity and 75C would apply? If yes then Thwn-2 is not in 75C. What would be new amapcitty be?
3. Is their such a thing inverter rated 90C or inverter terminal rated 90C?
4. How does 110.14(C) apply to inverter terminals or inverter temp rating?
I appreciate your input. Not trolling but trying to clear things up please if possible forgive my ignorance.
Sent from my SM-G935U using Tapatalk