Patdown45
New User
- Location
- North Berwick Maine
- Occupation
- Mechanical Engineer
I have installed a 7.2 kw ground mounted solar array that is running 48 modules consists of (46)180 watt Trina modules & two 100 rich solar modules. Running four pairs of modules that are in parallel to create 360 watt inputs to each of the 6 QS-1 1200 watt microinverters. The manufacturer instructions that 3 QS-1 be on a 20amp circuit so I have 2 strings that are going back to my subpanel in the garage that is a 125 amp bus so I am allowed up to 50amps backfed however the main panel is a 200 amp and thus I am only allowed 40amps because the breaker feeding the subpanel is at the end of the bus in the main and the 20amp backfed breakers are also at the end of the buss in the subpanel but are on the same side. My questions are as follows:
Q1 should I put the 2 backfeed breakers one on each leg on the subpanel at the end to more evenly distribute the load?
Q2 there is only 3 wires in the trunk line from the microinverters L1 L2 and a green ground no neutral, will this present problems in the future? I have already passed my AHJ but he was here for 3 minutes and had no questions a little disheartening after studying the 2014 NEC for 2 weeks I had been prepared for the worst but was unable to get a master electrician to come out.
Q3 What is the best way to prevent lightning protection for a ground mounted system where there is no high voltage DC using microinverters? Currently besides the ground on the microinverters that is going thru the subpanel to the main panel to the ground rod at the main panel ground rod. I also installed 2 additional ground rods at both ends of the solar array which has all the metal piping and metal frames of all the modules as well as the metal exterior of the microinverters all connected with #6 bare continuous as well as the 2 disconnect metal switch boxes.
My real concern is the lack of history and reviews on the AP systems microinverters and my main breaker in the garage subpanel recently failed and was only delivering one leg, it was new in 2007 and I replaced it with the same and everything seems fine, but I find the timing too coincidental....not a believer in that. Also earl in my testing I noticed one of the legs on the trunk cable got so hot it melted the connector as it was only visible after I was able to pry the connector apart I no that the heat was internal not from the outside but from the current. I repaired the connector and have had no issues since, but am I being paranoid or is there something I have done wrong here?
Q1 should I put the 2 backfeed breakers one on each leg on the subpanel at the end to more evenly distribute the load?
Q2 there is only 3 wires in the trunk line from the microinverters L1 L2 and a green ground no neutral, will this present problems in the future? I have already passed my AHJ but he was here for 3 minutes and had no questions a little disheartening after studying the 2014 NEC for 2 weeks I had been prepared for the worst but was unable to get a master electrician to come out.
Q3 What is the best way to prevent lightning protection for a ground mounted system where there is no high voltage DC using microinverters? Currently besides the ground on the microinverters that is going thru the subpanel to the main panel to the ground rod at the main panel ground rod. I also installed 2 additional ground rods at both ends of the solar array which has all the metal piping and metal frames of all the modules as well as the metal exterior of the microinverters all connected with #6 bare continuous as well as the 2 disconnect metal switch boxes.
My real concern is the lack of history and reviews on the AP systems microinverters and my main breaker in the garage subpanel recently failed and was only delivering one leg, it was new in 2007 and I replaced it with the same and everything seems fine, but I find the timing too coincidental....not a believer in that. Also earl in my testing I noticed one of the legs on the trunk cable got so hot it melted the connector as it was only visible after I was able to pry the connector apart I no that the heat was internal not from the outside but from the current. I repaired the connector and have had no issues since, but am I being paranoid or is there something I have done wrong here?