GT grounding question

[khanh dam]

Any help with grounding questions shown in pictures appreciated. I have an inspection on 11/27/20 and need to pass.
IMG_4769.jpgIMG_4766.jpgIMG_4767.jpgIMG_4765.jpgIMG_4768.jpg

[solarix]

All metal wireways need to be bonded to ground. The conduit does not have to be bonded to the boxes (the old way of bonding), your inspector is going to want grounded bushings on each conduit. Our inspector requires a bond bushing on each end of the DC conduit.

AC and DC wires can run together (they both have 600V insulation) alhough some inspectors won't allow it.

You can run the grounding wire either inside or outside the conduit. If outside it needs to be more durable (6awg minimum). If inside on a long conduit run, it is supposed to be bonded at both ends as the conduit acts as a choke to current spikes.

Ask your inspector what they want on the ground rod question. Opinions vary...

How come you are installing an ~8 year old inverter? That looks like a second generation SunnyBoy....

Do the next guy a favor and label your DC wiring please...

[khanh dam]

THANKS FOR THE ANSWERS. I will have to see if my local electrical supply company has the grounded bushings in stock early monday morning to be compliant with nec 250.97

. Also need to get proper green colored ground screws NEC says self tapping metal screws I used are not allowed.nec 250.8

I read that NEC requires the negative PV wires to be taped white to meet code nec 200.6 so will label them more clearly when I do that.

Still have not figgured out if I need to have a DC ground for each inverter? The sunny boy DC disconnect box has a specific grounding area for that. Any thoughts on that?
I got several of the new Sunnyboys still in box from a company going out of business several years ago. I think for around $400 each. Only downside is by the time you buy the DC disconnect and monitoring boards that adds about $300 to each inverter. Still cheaper than buying a " current inverter" I've read the old sunny boys are easier to fix as well, so that might be a plus going forward. sunny disconnect.jpg

[Mike90250]

New GT systems may need to meet current NEC requirements, not what was in effect when inverters were built. Maybe all the inverters need is a firmware update. Maybe the inspector won't notice.....

[khanh dam]

2008 sunny boy's meet current NEC standards for anti islanding, GFPD, grounding, etc. you are assuming something that is not an issue.

[Mike90250]

2008 sunny boy's meet current NEC standards for anti islanding, GFPD, grounding, etc. you are assuming something that is not an issue.

There's the Rule 21, which some areas (Calif & Hawaii) which mandates smart inverters. ( 2017 ) So it's not NEC but different states utilities are imposing this requirement, Look up the requirement for your location/utility. City may let you install gear, but you will be unhappy if the Power Company says you cant connect it to their grid.

https://www.solarpowerworldonline.com/2017/08/solar-new-rule/

excerpt :
Under the UL 1741 safety standard established in 2010, the old interconnection requirements only allowed inverters to operate within a narrow range of IEEE frequency and voltage requirements. “Because of all this, the capability of inverters wasn’t fully utilized,” John Drummond, applications engineer at Chint Power Systems, explained during a recent Solar Power World webinar. “But the revised rule is leading the way to expand that.”

The revised rule widens the range of conditions during which inverters may operate. The new rule and the addendum to the previous UL safety standard, UL 1741-SA, allow inverters to provide seven grid support functions:
-Voltage ride-through
-Frequency ride-through
-Soft-start reconnection
-Ramp-rate controls
-Fixed power factor
-Dynamic Volt-VAR management
-Changes to anti-islanding requirements

[khanh dam]

Luckily Duke Energy does not require rule 21 compliant inverters in my area. And since this install is not on a habitable structure, I dont' need rapid shut down.

[bob-n]

As you route the wire to the ground rod, consider the high current flowing in that wire when your roof gets a near hit or direct hit from lightning. If possible, you want that energy routed to earth without connecting to any other devices along the way. Best case is something like this:
ground.png