New Ground Mount Installation in San Diego

[Hillsider]

Ground-Mount Optimizer Installation

I have been following your installation progress with much interest, as I am putting together my drawing package & budget spreadsheet for a similar ground-mount array. I noticed on one of your photos ( #7 ) from your 3/29/15 post, that the optimizers are installed in the side-slot of the IronRidge rail, parallel to the plane of the solar panel. The product description of the P300 optimizer shows a mechanical mounting slot on the optimizer that facilitates mounting flush with the rail, but perpendicular to the panel. Did the installer use a right-angle T-bolt to attach it, or does SolarEdge offer an adapter to allow for that manner of attachment? BTW, if it is convenient, I would appreciate a PM from you, regarding your installer, as I am still on the fence about a self-install vs. contract job.

[foo1bar]

I have been following your installation progress with much interest, as I am putting together my drawing package & budget spreadsheet for a similar ground-mount array. I noticed on one of your photos ( #7 ) from your 3/29/15 post, that the optimizers are installed in the side-slot of the IronRidge rail, parallel to the plane of the solar panel. The product description of the P300 optimizer shows a mechanical mounting slot on the optimizer that facilitates mounting flush with the rail, but perpendicular to the panel. Did the installer use a right-angle T-bolt to attach it, or does SolarEdge offer an adapter to allow for that manner of attachment? BTW, if it is convenient, I would appreciate a PM from you, regarding your installer, as I am still on the fence about a self-install vs. contract job.

What I've seen for optimizers they're mounted to the top of the rail (panel side of the rail) and they are parallel with the panel.
For example, at 1:05 in this video https://www.youtube.com/watch?v=wLoF9rMlmWk

The #7 photo in post #4 of this thread shows the same mounting - just viewing from below, while the video angle is shot from above the optimizer

My optimizers are mounted the same way - bolts in the top channel of the rail - using the same channel that is used for the clamps holding the panels.

BTW the bolts don't come with the rail or the optimizer - so plan on purchasing them separately. I bought those stainless-steel bolts, washers, and lock-nuts from Home-Depot.

[Hillsider]

Top Mounting of SolarEdge Optimizers

What I've seen for optimizers they're mounted to the top of the rail (panel side of the rail) and they are parallel with the panel.
For example, at 1:05 in this video https://www.youtube.com/watch?v=wLoF9rMlmWk

The #7 photo in post #4 of this thread shows the same mounting - just viewing from below, while the video angle is shot from above the optimizer

My optimizers are mounted the same way - bolts in the top channel of the rail - using the same channel that is used for the clamps holding the panels.

BTW the bolts don't come with the rail or the optimizer - so plan on purchasing them separately. I bought those stainless-steel bolts, washers, and lock-nuts from Home-Depot.

Thanks for the installation video reference. Photo #7 viewing direction obscured the side-slot of the rail, so it didn't really show the optimizer's point of attachment. From the video it looks like the only caution to be observed for top-mounting each panel's optimizer on one of it's rail-pairs ( between the mid-clamps ) is to use a mounting bolt that does not protrude above the surface of the optimizer, farther than the distance between the bottom of the panel frame, and it's lower surface.

[Hillsider]

Conduit Run Details

To the OP ... I have referred back to your pics & narrative several times, as I proceed to fine-tune my own ground-mount plans, & I have a couple of questions regarding the conduit run from your array up to your back yard; also one regarding your array junction box. Your narrative seemed to indicate that your wire-pull operation occurred after the down-hill conduit run was covered. I am planning to lay my 5 THWN-2 conductors from the array to the inverter inside the 120' 1" PVC & LFMC conduit as I assemble it & lay it in the trench. I have pulled as many as three #12 AWG conductors through 50' if conduit with lube & fisch-tape, but would hesitate to pull 5 #8 conductors 70-80'. One of your pics showed your red, black & green conductors "emerging" from the conduit, so I assume the pull was done before the trench covering (??). In the same pic, I couldn't tell how many conductors, total, that you ran underground. Did your installer run two parallel strings + EGC back to the inverter?
The open view of your junction box did not show any obvious bus-bars, so I could not determine how your installer joined the USE-2 cables to THWN building wire conductors. I am planning on using a Wiley ACE transition box, with DIN rails, to make the junction. I believe the 2011 NEC rules allow the run to be made without an OCPD device, as long as no more than 2 parallel DC strings are run together. Comments, anyone?

GS

[lkstaack]

Unfortunately, I wasn't present when they pulled wire, so my knowledge is limited to what you see in the photos.

[foo1bar]

I am planning to lay my 5 THWN-2 conductors from the array to the inverter inside the 120' 1" PVC & LFMC conduit as I assemble it & lay it in the trench.

Wires are always supposed to be pulled AFTER the conduit is completely in place.
Gluing up conduit around the wires is not a code compliant installation.
AFAIK gluing conduit around a pull rope is OK. (But a rag with a string and a vacuum cleaner works fine for getting the initial string through - at least on 50' it works well, I think it'd work fine even on 120' )

If you're really worried about it, for ~$50 I'd go for 1.5" instead of 1".
I'm guestimating $50, because 12 lengths at ~$3 extra plus a little for larger fittings.

[bcroe]

(But a rag with a string and a vacuum cleaner works fine for getting the initial string through - at
least on 50' it works well, I think it'd work fine even on 120' )

It worked at 220' here. Needed to run power out there to operate the vacuum. Bruce Roe

[Mojave]

Can you break down (or at least estimate) the pricing? $4.65/watt. I can look up pricing on the panels, but how much for the trenching, mounting, wiring, etc.? Or was it just a quoted price for the whole system?

I'm also in San Diego and looking to do a ground mounted system but on flat ground. I'm on a canyon, but it's north facing and I have shading on my roof, and the roof itself is very new. The land has no shading except maybe mid-winter and sits empty with only ice plant.

Also, what is the total square footage of the 7x3 panel layout?

Thanks for a great and informative read.

[Lpotter86]

Looks good.

[Hillsider]

Pulling conductors through conduit

Wires are always supposed to be pulled AFTER the conduit is completely in place.
Gluing up conduit around the wires is not a code compliant installation.
AFAIK gluing conduit around a pull rope is OK. (But a rag with a string and a vacuum cleaner works fine for getting the initial string through - at least on 50' it works well, I think it'd work fine even on 120' )

If you're really worried about it, for ~$50 I'd go for 1.5" instead of 1".
I'm guestimating $50, because 12 lengths at ~$3 extra plus a little for larger fittings.

I couldn't find a specific NEC prohibition re "gluing PVC around the wires, but I'll take your word for it. Likewise, your suggestion to go to 1-1/2" PVC has merit. I am not too concerned about the added cost of the larger PVC run, as I am planning on 7 10' lengths, but boosting the remaining 50' of Liquid-tight flex conduit to 1-1/2" can get really pricey. To make the entire run in PVC would be a labor-intensive nightmare, as the last stretch has to navigate around a couple of trees, under a low block wall & under a walkway behind the house. I have never tried using string for pulling any conductors farther than 30' in 1/2" EMT, & prefer the "security" of a 50' fisch-tape. For those like Bruce, who have used cordage for pulling cables through 100'+ of conduit, is it correct to assume you initially vacuum through a light cord, tied to some light material, then progress to heavier cordage to actually yank the conductors through. Is it allowable to do a partial pull through buried PVC, then do a separate pull through un-buried LFMC ( since that type of conduit is ok both buried & exposed ), and then bury it after the pull? Just asking.

[foo1bar]

I couldn't find a specific NEC prohibition re "gluing PVC around the wires,

https://ia700805.us.archive.org/20/items/gov.law.nfpa.nec.2011/nfpa.nec.2011.pdf

300.18

PVC conduit is a raceway - and it says raceways shall be installed complete "prior to the installation of conductors"

50' of Liquid-tight flex conduit to 1-1/2" can get really pricey. To make the entire run in PVC would be a labor-intensive nightmare, as the last stretch has to navigate around a couple of trees, under a low block wall & under a walkway behind the house.

I'd look at another option if possible...
Maybe a direct-burial cable would be better option. (Not sure what the rules would be for that - haven't had to look into that)
With your current plan - I'm not sure how you'd transition to liquid tight flex.
And I don't know how well that's going to work pulling through 50' of it as it snakes around trees and such.

[SunEagle]

I couldn't find a specific NEC prohibition re "gluing PVC around the wires, but I'll take your word for it. Likewise, your suggestion to go to 1-1/2" PVC has merit. I am not too concerned about the added cost of the larger PVC run, as I am planning on 7 10' lengths, but boosting the remaining 50' of Liquid-tight flex conduit to 1-1/2" can get really pricey. To make the entire run in PVC would be a labor-intensive nightmare, as the last stretch has to navigate around a couple of trees, under a low block wall & under a walkway behind the house. I have never tried using string for pulling any conductors farther than 30' in 1/2" EMT, & prefer the "security" of a 50' fisch-tape. For those like Bruce, who have used cordage for pulling cables through 100'+ of conduit, is it correct to assume you initially vacuum through a light cord, tied to some light material, then progress to heavier cordage to actually yank the conductors through. Is it allowable to do a partial pull through buried PVC, then do a separate pull through un-buried LFMC ( since that type of conduit is ok both buried & exposed ), and then bury it after the pull? Just asking.

Off the top of my head I believe there is also a maximum of 4 of 90 D bends allowed in a conduit run before you are required to add a fitting (C or LB) or box as a "pull" point.

You can also rent those blowers that will push a "plug" with a "pull" string attached through a long conduit run.

[foo1bar]

Off the top of my head I believe there is also a maximum of 4 of 90 D bends allowed in a conduit run before you are required to add a fitting (C or LB) or box as a "pull" point.

Yes - 360-degrees of bends.
(could be four 90s, or two 90, three 45s, and three 15's. Or any other combination)

BUT IIRC, I think C/LB/LL/LR aren't allowed to be buried. Couldn't point you to what section of code that's from offhand though.
A christy box with a heavy or locking cover is how you should do a pull point.

[bcroe]

Yes - 360-degrees of bends.
(could be four 90s, or two 90, three 45s, and three 15's. Or any other combination)

BUT IIRC, I think C/LB/LL/LR aren't allowed to be buried. Couldn't point you to what section
of code that's from offhand though.
A christy box with a heavy or locking cover is how you should do a pull point.

As I recall, we pulled 4 #6 and a #8 through 220' of pretty much straight 1.5" PVC with
plenty of wire hanging out the ends. I would hate to try pulling that around even one
right angle. All that was underground, then an angle and 2 foot riser were glued on to
the ends to bring it out of the ground to a box. Bruce Roe

[SunEagle]

As I recall, we pulled 4 #6 and a #8 through 220' of pretty much straight 1.5" PVC with
plenty of wire hanging out the ends. I would hate to try pulling that around even one
right angle. All that was underground, then an angle and 2 foot riser were glued on to
the ends to bring it out of the ground to a box. Bruce Roe

That is why they make that Blue and Yellow pulling soap. It does cut down on the friction but you have to use the correct one for either inside or outside conduit runs or that stuff hardens up like concrete.