Green Building Forum - Attaching PV using clamps

Attaching PV using clamps

ComeOnPilgrim — Fri, 05 Apr 2024 15:34:27 +0100

Follow up question to my earlier one. I have a standing stream roof that uses S-5-E clamps. These have a vertical thread for an M10 bolt. Was wondering how to attach a rail for the panels to this and whether there needs to be a gap between the panels?

Attaching PV using clamps

philedge — Fri, 05 Apr 2024 17:27:02 +0100

Have a look at Renusol part 420131 which their rails fasten to. I don't know if gaps are necessary but it's standard practice. Ask the panel manufacturer??

Attaching PV using clamps

djh — Fri, 05 Apr 2024 20:38:21 +0100

The S-5-E has two vertical threaded holes, I believe, according to https://www.s-5.com/ (use the Project dashboard and then Configurator if necessary). The Mini clamps have just one, I think.

ejot have some useful looking guides at https://www.ejot.co.uk/Building-Fasteners/Products/Solar-products/Solar-fasteners/S-5-PV-Kit-/p/S-5_PV_Kit_excl_clamp such as:

https://www.ejot.co.uk/medias/sys_master/products/products/h5b/h4b/9107016286238/S-5-PV-Kit-Installation-guide-en-GB.pdf

The gaps arise naturally as a result of the clamping mechanism.

Attaching PV using clamps

philedge — Sat, 06 Apr 2024 09:33:58 +0100

If you use standard rails and mid clamps then yes a circa 25mm gap is needed for the clamp to fit between panels. That's not the case for a gap left between rows where there's no clamp but a gap always seems to be left. Maybe it's for aesthetics so there's a uniform gap all round the panel??

We have a ground array on a wooden frame where the panels are clamped to the wood with stainless wood screws and large washers bearing on the panel frame so the gap there is 6mm ish. If you bolt panels in place using the mounting holes on the backs of the frames then you could have no gap. Whether you need a gap I guess would be for the manufacturer to say??

Attaching PV using clamps

djh — Sat, 06 Apr 2024 11:09:51 +0100

Posted By: philedgeMaybe it's for aesthetics so there's a uniform gap all round the panel??

Or thermal expansion? Aluminium expands quite a lot when it gets hot.

If you bolt panels in place using the mounting holes on the backs of the frames then you could have no gap.

I'm curious; how do you tighten the bolts?

Attaching PV using clamps

RobL — Sat, 06 Apr 2024 12:20:51 +0100

Aluminium coefficient of expansion is 23E-6/degC, wood is around 4E-6/degC. So if a 1m wide panel heats up by 100C maximum from winter to summer, it needs a 2mm expansion gap I think, to avoid stress.

Attaching PV using clamps

philedge — Sat, 06 Apr 2024 16:57:48 +0100

@djh. For ground arrays there's access to the back of the panels. For roof mounted you'd need to hire an orangutan

Attaching PV using clamps

revor — Sat, 06 Apr 2024 17:06:28 +0100

My ground array is on an Renusol aluminium frame. The brackets holding down the panels comprise of a sprung "nut" which fits in the frame verticals, and a capping bracket which is rebated and fits over the adjacent panels, the rebates maintain a distance of 23 mm between panels. A bolt goes through the cap and is torqued up to the specified amount and as it tightens it pulls the bracket containing the nut tight into the verticals of the frame and clamps down the frame of the panel. What is often missed as far as I can make out is that the frame needs grounding with a ground earth rod and to ensure good contact throughout the entire array a special thin SS rectangular U shaped flat plate with slight barbs on it is fitted between the panel frame and aluminium frame which bite through the powder coating to make the contact. The panel earth must not be connected to the inverter/house earth.

Those interested will find a drawing in this guide.

https://www.renusol.com/files/content/Downloads/Zubeh%C3%B6r/20210915_All_Languages_P-Clip_InstallationGuide.pdf

Attaching PV using clamps

djh — Sat, 06 Apr 2024 18:12:53 +0100

Posted By: philedge@djh. For ground arrays there's access to the back of the panels. For roof mounted you'd need to hire an orangutan

Ah yes. I was still on a standing seam roof with its fittings.

Attaching PV using clamps

philedge — Sun, 07 Apr 2024 14:29:13 +0100

I had a look at the rear frame fixing holes on our ground array panels and the holes are only 300mm in from the ends so easily reachable for a single row of roof mounted panels if you wanted to do away with the clamps to close up the gaps. 2 or more rows of panels would be a challenge to get the fourth bolt in, but maybe doable with sliding channel nuts in unistrut and a long reach spanner??

Attaching PV using clamps

revor — Mon, 15 Apr 2024 13:10:40 +0100

I am truly stuck cannot start new thread as says am not signed in when I am so cannot post. If I may will hijack this discussion to post following.

Getting an EV at last this week. Been looking at Octopus Intelligent Go and the way I read it you can get your cheap electricity at night as well as exporting during the day at fixed 15p per Kwh. Last time I looked into it you could not have both when you had outgoing tariff.
.
Seems win win if I read correctly. I would instinctively charge during the day using solar that would normally go to export but looks like best to export for 15p and buy back at 7.5p at night during the 6 hour slot. Seems to be to good to be true.

Anyone on here that can comment on it.?

Attaching PV using clamps

djh — Mon, 15 Apr 2024 17:57:25 +0100

Posted By: revorI am truly stuck cannot start new thread as says am not signed in when I am so cannot post.

I just used Firefox to start a new discussion for you without any problem. I'd recommend changing your browser.

Attaching PV using clamps

ComeOnPilgrim — Fri, 26 Apr 2024 00:06:38 +0100

I think the small gap (20-25mm) is for ventilation / cooling the panels to improve efficiency.

Attaching PV using clamps

ComeOnPilgrim — Fri, 26 Apr 2024 00:11:14 +0100

@revor, how are the rails attached to the roof itself?

Attaching PV using clamps

revor — Fri, 26 Apr 2024 07:50:24 +0100

Posted By: ComeOnPilgrim@revor, how are the rails attached to the roof itself?

My array is ground mounted to concrete blocks rebared and concreted in the ground and levelled in between with gravel. If you google Renusol think you will find roof mounts as my system is designed for roof mounting.
Bing brought up this link.

https://www.renusol.com/en/

and google this

https://www.bing.com/search?q=renusol+mounting+system&form=ANNNB1&refig=9fe50d2a5f494dbd8fd91e4727842e51&pc=HCTS&adppc=EDGEESS&sp=2&lq=0&qs=AS&pq=renusol+&sk=LS1&sc=10-8&cvid=9fe50d2a5f494dbd8fd91e4727842e51

Attaching PV using clamps

djh — Fri, 26 Apr 2024 10:22:07 +0100

Posted By: ComeOnPilgrim@revor, how are the rails attached to the roof itself?

I'm not revor. But you said at the start that your roof used S-5-E clamps? How the rails are attached to the roof depends entirely on what brand/type of standing seam roof you have. You might want to ask the manufacturer if you're not sure. It will affect their warranty.

Attaching PV using clamps

ComeOnPilgrim — Fri, 26 Apr 2024 12:18:40 +0100

@djh, I know how S5N clamps are attached to the roof, but I was wondering how the Renusol system attaches to the roof, ie, it is the connection to the rail side that I am interested in as somehow I will need to replicate this using the S5N connection. Ie the S5N connection has two sides - 1. to the roof (I know how this works) and 2. to the rail (I don't know how this works). The second one is what I am trying to find out.

Attaching PV using clamps

ComeOnPilgrim — Fri, 26 Apr 2024 12:21:41 +0100

@revor, thanks! I think the L-bracket and clip shown in the photo here is what I need: https://www.renusol.com/en/solar-panel-mounting/metal-roof/standing-seam-connections/

Attaching PV using clamps

revor — Sat, 27 Apr 2024 11:24:31 +0100

Posted By: ComeOnPilgrim@revor, thanks! I think the L-bracket and clip shown in the photo here is what I need: https://www.renusol.com/en/solar-panel-mounting/metal-roof/standing-seam-connections/

If you contact Renusol for information you will find them very helpful. They did a wind load calculation for our location and a list of all the parts I needed including the size of the Hilti anchor bolts to hold it all down to the blocks. One of the most helpful companies have dealt with.

Attaching PV using clamps

djh — Fri, 24 May 2024 17:54:29 +0100

https://www.altenergymag.com/story/2024/05/metal-roof-solar-project-survives-category-5-hurricane-winds/42102/