Mounting hooks - numbers and spacing

[Tadmeister]

Hi everyone,
Hope you are well.
Im trying to work out how many hooks I need and the max spacing of the hooks for roof mounted panels. I have a shallow pitched roof with concrete tiles and want to have 1 line of 5 panels and 1 line of 4 panels above - all in portrait. The panels are canadian solar ones and are 1.048m x 2.108m. For the 5-panel row, If I had 5 hooks on each rail and the two end ones were 30cm in from the ends then the spacing would be 1.20m at best (depending on positioning of the rafters). For the 4 panel row with 4 hooks it would be 1.236m. So in both case the spacing would be slightly wider than the panel width possibly a bit wider depending on the rafters.
I appreciate that ideally a structural engineer should be working out the stresses/forces involved but I was wondering if there was a rough rule of thumb on this. Looking at my neighbours set up, the hook spacing seems very far apart. I cant seem to find anything on this on the installation guide published by renusol (https://www.renusol.com/files/content/D ... nGuide.pdf).
Any insights would be greatly appreciated.
Cheers
Tom

[smegal]

Have a look at the "renusol configurator" if you put your details in, it should give you a parts list.

[Sim_C]

I would expect the 'Renusol Configurator' will provide the minimum number/maximum spacing of hooks required to resist the relevant forces on the panels, but the spacing on your roof rafters will actually dictate how many you need to fit.

If Resusol state every 800mm, and your rafters are every 600 mm, then you need a hook for each rafter.

If Resusol state every 800mm, and your rafters are every 400 mm, then you need a hook for every other rafter.

[ClockmanFRA]

With your PV rail support brackets at 1.23m sounds okay, but depends on what the PV Rails can actually take.

I don’t have anything to do with the UK loadings. France and Europe have some strange roof constructions.

Depends on roof joist spacings and weight of panels and type of PV mounting rails.

15 years ago, PV rails, Grasol, Rensol, Fisher and the like, were made with plenty of material, today they are minimal.

Rule of thumb here in France for the latest panels is 1.4m max spacing but 1.3m is probably safe with the heavy duty K2 rails for Rail support brackets.

Whenever a new PV rail comes out, they are always changing, i actually do a physical test on it to see what the deformation and loading is, especially as the PV panels get bigger and bigger and very heavy and no longer a single person job.

I have detailed and put a rough guide with photos on my rambling web site.....

The Different stages of fitting a 3.6kW PV Photovoltaic Installation to a Slate Roof.

https://www.bryanhorology.com/pv-photov ... ations.php

I Trust this helps.

[Joeboy]

My last set of panels up were on a 10 deg roof and I set the brackets at 1.2mtr separation. Still there.