erickench
Senior Member
- Location
- Brooklyn, NY
Okay here's another doozy that I would like to share with you guys as I get my proposals ready. The above exception seem's to be in conflict with the OCPD/Ampacity rules of NEC 690.8(B). It states the following:
(b) The short-circuit currents from all sources do not exceed the ampacity of the conductors or the maximum overcurrent size specified on the PV module nameplate.
Now here's my argument:
Part (b) of this exception permits a code user to ignore the ampacity and overcurrent protection rules in NEC 690.8(B). It is already a given that conductor ampacites and overcurrent protection must be sized at a minimum that is well above the module rated short-circuit current in accordance with NEC 690.8(B). Also, the maximum OCPD nameplate rating is always going to be much higher than the module rated short-circuit current, so this is also a given. If the ampacity is somewhere between the module rated short-circuit current and the values calculated in NEC 690.8(B)(2) this would be a violation of that NEC section. If the ampacity is somewhere between the maximum OCPD nameplate rating and the values calculated NEC 690.8(B)(2) this would be in compliance with that section because conductor ampacity must not be less than the OCPD rating as calculated in NEC 690.8(B)(1) unless NEC 240.4(B) would apply. However, in both cases overcurrent protection is still required by NEC 690.8(B)(1).
So tell me what you guys think.
(b) The short-circuit currents from all sources do not exceed the ampacity of the conductors or the maximum overcurrent size specified on the PV module nameplate.
Now here's my argument:
Part (b) of this exception permits a code user to ignore the ampacity and overcurrent protection rules in NEC 690.8(B). It is already a given that conductor ampacites and overcurrent protection must be sized at a minimum that is well above the module rated short-circuit current in accordance with NEC 690.8(B). Also, the maximum OCPD nameplate rating is always going to be much higher than the module rated short-circuit current, so this is also a given. If the ampacity is somewhere between the module rated short-circuit current and the values calculated in NEC 690.8(B)(2) this would be a violation of that NEC section. If the ampacity is somewhere between the maximum OCPD nameplate rating and the values calculated NEC 690.8(B)(2) this would be in compliance with that section because conductor ampacity must not be less than the OCPD rating as calculated in NEC 690.8(B)(1) unless NEC 240.4(B) would apply. However, in both cases overcurrent protection is still required by NEC 690.8(B)(1).
So tell me what you guys think.