Position of rails/clamps

[ktech]

The rail spacing wouldn't be acceptable for us. Also looks like no thermal expansion gap has been allowed between rows. We generally use a 20mm spacer to line up between rows. Apart from the thermal expansion this gives a nice uniform look to the array. Ge them back to sort it.

 

[jupestar]

yep get them to fit an expansion gap between the rows. this is very important otherwise there is continual pressure on the frames, which will slowly damage them. Also need better positions on the clamps to be honest. We nearly always cross rail it to get the fixings on the large side. Regardless of manufacturers warranties.

 

[Vegelen]

Are they connected to transformerless inverters?
If so, earthing of the array frame may need to be done.

 

[Gavin A]

Are they connected to transformerless inverters?
If so, earthing of the array frame may need to be done.

thread takes off.

 

[Vegelen]

Lol

 

[Gavin A]

*gives thread a kick*

[h=2]Array frame earthing and transformer-less inverters[/h]One reason I am frequently asked about the publication date for the new guide is due to the proposed changes to array frame earthing on systems with transformer-less inverters. This section of the guide has not changed significantly from the published draft and I do not foresee any alterations prior to publication. As the new (draft) guidelines are widely accepted throughout the industry many of the MCS certification bodies (eg Elecsa) permit installers to operate to the new guidelines. My message to any installers who ask about this, is to suggest talking to their certification body and seeing if the CB can provide, in writing, that you can follow the new guidelines.

[source - one of the DTI guide vs3 teams blog]

 

[wstevew]

Are they connected to transformerless inverters?
If so, earthing of the array frame may need to be done.

Strange you should say that I believe they are going to try bonding the array to see if the 601 errors go away.

Apparently they are going to arrange a date to re-scaffold and re-fit the whole lot (both east and west arrays).

 

[Vegelen]

I once saw a SMA 3000 TL get installed with the array frames not earthed.
I monitored this system versus a similar local solar pv system.
I watched the 2 systems comparitive efficiencies change over time with the weather.
The array frame then got earthed and the comparitive performance between the 2 systems radically changed.
The 2nd system started to outperform the 1st. I never fully understood why.
SMA recommend their transformerless TL inverters should have the solar array frames earthed.
Solar pv arrays create stray capacitance.
Earthing the arrays creates a pathway for stray capacitance to discharge.
If you earth the arrays and still get the same error, it may be caused by something else.

 

[wstevew]

Yes he said industrial welding nearby can dump. Dc. Into the grid.

I said highly unlikely they time there welding to be approx 15 mins before or after feed in. (That's when I get the error)

 

[wstevew]

I have had this response from my installer.


"I have spoken to everyone, and the solution we have come up with is to take off the panels from the roof put in the extra cross rail and re site the panels on to both rails.

Doing this however will cause the panels to sit around 200mm from the roof itself. Would this be acceptable to you?

If you would like to go ahead we would need to erect scaffolding to reach the panels."


Now I'm a bit concerned as I think they are not far off 200mm already and have had pigeons going under them.

Your opinions will be appreciated as always.

I have replied with my concern and asked how many cross rails and how they will fit when the existing rails are cut to length. Also if they intend to leave the current rails where they are.

 

[SolarCity]

Why do you need cross rails? Can the rails be positioned better instead?

 

[wstevew]

I don't know why perhaps they want to fix cross rails to the existing rails without moving them. I have no idea if that will work anyway. I thought moving 2 rails on each array would be the answer.

In my reply I suggested moving the top rail up a course and bottom rail down a course. As suggested on here and I await their response.

 

[Gavin A]

how many tiles are there above the top panel before the gutter?

only justification I can see for using cruciform mounting is if they'd be needing to put a bracket under the first or second tile below the ridge and they're worried about disturbing the ridge.

whatever they did they'd need to be sure the panels weren't over 200mm off the tiles or it'd breach the permitted development regs.

 

[wstevew]

how many tiles are there above the top panel before the gutter?

4 Tiles above panels (10 tiles from ridge to gutter).

 

[moggy1968]

no bother then