Neal30
Member
- Location
- Gainesville, ga, USA
I have been looking at an 1,000VDC Ungrounded string inverter. The manufacturer states that there is no fusing required on the DC side of this inverter. The reasoning behind this is that the inverter has three separate MPPT channels internally. Each channel only accepts two strings. The NEC code that they reference on OCPD is the one about no more than two strings and the sum of all potential currents not exceeding the amp rating of the conductor. It makes me a little weary not having any DC fuses, especially in this case where both the positive and negative would be fused. The manufacturer worked hard at explaining the logic and the interpretation, but from a risk reward standpoint, I would like to hear how some other industry professionals would weigh in here. We are talking about dropping 43 of these inverters in a field in a utility style project.
My thought is that even though the MPPT channels are separated the wires would all be in close proximity inside the inverters termination housing.
If none of the strings have a relationship to the ground anywhere, and they are not more than two parallel circuits inside the inverter, that could potentially impose more current due to the seperate mppt channels, than the instance where more than two circuits could be paralleling and have a combined current would be Nell? How are the MPPT channels isolated would be a question. It is very interesting, and I kind of rambled there for a minute but it seems that I answered my own question. I still would like to here some thoughts, if anyone is interested. Thanks!
My thought is that even though the MPPT channels are separated the wires would all be in close proximity inside the inverters termination housing.
If none of the strings have a relationship to the ground anywhere, and they are not more than two parallel circuits inside the inverter, that could potentially impose more current due to the seperate mppt channels, than the instance where more than two circuits could be paralleling and have a combined current would be Nell? How are the MPPT channels isolated would be a question. It is very interesting, and I kind of rambled there for a minute but it seems that I answered my own question. I still would like to here some thoughts, if anyone is interested. Thanks!