First DIY 6k install. How do the plans look so far?

Dustinbrwn

Hello everyone, New to the forum here but I have been lurking plenty trying to get a good grasp on things.
I recently purchased a home in central AZ and my location and home are about perfect for solar. I picked up 20 of the LG 300w ACe modules. (LG300A1C-B3) for a pretty good deal so no I have been reading up and working on the plans to turn in.
I plan on doing as much as the install as I can myself. The one thing I am lacking knowledge in is the electrical side of things, and more trying to make sense of the codes, and remember them.
I will be having a licensed electrician make all the necessary connections to the sub panel and make sure everything else is up to code. 
So quick rundown of what my plans are....(and forgive me if i misuse terminology here, feel free to correct me)

The inverter specs are 305w, at 96.5% efficiency and 1.27amps.

This will be a roof mount on a standing seam metal roof. Using the S-5-N mini clamps with the S-5! PV kit to attach. 4 attachment points per panel.
I will have the panels split into runs of 11 or 12 and 8 and 9. Those will combine at a J-Box on the roof, then to 6g XHHW-2 through 3/4 conduit down the roof, through the eve to a production meter, AC cutoff, and 100 amp, (125 buss) sub panel, which is feed by a 200a main panel. (200a buss) So far so good? A quick few questions. First about grounding..with the "built in" mico inverters, they have internal GEC, so no need to worry about that, just the L1, L2, and neutral correct? With the EGC, do I have to run that to my main breaker box or could I tie that into a pre-existing lighting protection ground? I have multiple lighting rods on my roof peak, all tied together with the mesh style grounding wire running to multiple grounding rods on opposite corners of the house.
Another quick question about the neutral. With a 240v single phase, I read here that I could go lower AWG with the netural, up to 2 lower or possibly more? If I can save a dime on wire im all for it.
Thats just the basic setup with a few questions I have at this point. 
Any Input would be appriciated
Thanks
Dustin

Ethan Brush

Dustinbrwn said:

Hello everyone, New to the forum here but I have been lurking plenty trying to get a good grasp on things.
I recently purchased a home in central AZ and my location and home are about perfect for solar. I picked up 20 of the LG 300w ACe modules. (LG300A1C-B3) for a pretty good deal so no I have been reading up and working on the plans to turn in.
I plan on doing as much as the install as I can myself. The one thing I am lacking knowledge in is the electrical side of things, and more trying to make sense of the codes, and remember them.
I will be having a licensed electrician make all the necessary connections to the sub panel and make sure everything else is up to code. 
So quick rundown of what my plans are....(and forgive me if i misuse terminology here, feel free to correct me)

The inverter specs are 305w, at 96.5% efficiency and 1.27amps.

This will be a roof mount on a standing seam metal roof. Using the S-5-N mini clamps with the S-5! PV kit to attach. 4 attachment points per panel.
I will have the panels split into runs of 11 or 12 and 8 and 9. Those will combine at a J-Box on the roof, then to 6g XHHW-2 through 3/4 conduit down the roof, through the eve to a production meter, AC cutoff, and 100 amp, (125 buss) sub panel, which is feed by a 200a main panel. (200a buss) So far so good? A quick few questions. First about grounding..with the "built in" mico inverters, they have internal GEC, so no need to worry about that, just the L1, L2, and neutral correct? With the EGC, do I have to run that to my main breaker box or could I tie that into a pre-existing lighting protection ground? I have multiple lighting rods on my roof peak, all tied together with the mesh style grounding wire running to multiple grounding rods on opposite corners of the house.
Another quick question about the neutral. With a 240v single phase, I read here that I could go lower AWG with the netural, up to 2 lower or possibly more? If I can save a dime on wire im all for it.
Thats just the basic setup with a few questions I have at this point. 
Any Input would be appriciated
Thanks
Dustin

Hi Dustin.  Nothing jumps out at me as being incorrect.  Run your EGC with the other conductors back to the sub panel.  Note  you will also need to bond the panels to the EGC.  The size of a neutral conductor is technically sized by a load calc, but cant be smaller than the size in table 250.122.  The "two sizes smaller" rule is very common rule of thumb for residential stuff and I have never been questioned on it.  If the neutral conductor is carrying negligible current and just being used for phase and voltage reference purposes, I would just go with the smallest size allowed. 

westbranch

  

Dustinbrwn said:

The inverter specs are 305w, at 96.5% efficiency and 1.27amps.

This  (305W, 1.27A)  looks like your PV specs...??? not the inverter which may be 96.5% efficient

Dustinbrwn

Ethan,
Thanks for the feedback. Yes, I will be bonding the panels. I was hoping I could just tie it into the lighting grounding cable and rod and save a bit of time and wire but its a short run so not a big deal. and thanks for the clarification on the neutral.
Westbranch,
noted. Yes. 300w panels. the inverter is rated at 305w at 96.5 efficient. 

Im sure as i progress I will be back with more questions and hopefully some pictures of the install soon!
Thanks!

vtmaps

Welcome to the forum,
Have you run your plans by your power company?  Have you spoken to your AHJ inspector?  The opinions you get here are irrelevant, compared to what the AHJ and power company say.

Just curious... why are you using microinverters?   One of the best reasons for using them is the impending requirement in NEC for module level disconnect from the ground.  Microinverters are perfect for that, but there are also other reasons to use microinverters.

--vtMaps

Dustinbrwn

vtMaps,
I am working on the plans now, and trying to get everything in order before i submit them, whats the reason for the questions. After months of research and reading the NEC, (my town on the 2011 edition)  power company and town requirements, along with searching this and other forums I believe I have most of it sorted out. Just a few questions arise here and there that is a bit confusing and just want to make sure im understanding things correctly.
As far as mico inverters go, I did go back and forth, but found a great deal on the LG AC modules for $1.05w. Also, doing the majority of the install myself I came to the conclusion that the micro would be a bit easier to install, as well as to expand in the future.