Radian Posted October 14, 2022 Share Posted October 14, 2022 I can't find anything on https://mcscertified.com/ that explicitly covers rules or recommendations about DC cable management. My expectations are based on the BS 7671 wiring regs. which would not permit cables to flop about unsecured. But that's what I see when I look up under the modules on my roof: Is this supposed to be acceptable? Link to comment Share on other sites More sharing options...
TonyT Posted October 14, 2022 Share Posted October 14, 2022 I agree but if you needed to lift a panel out for repair you would need the slack? Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 14, 2022 Share Posted October 14, 2022 The cables have a degree of ‘mechanical protection’ from being behind the panels. No harm will come to them in actuality, and they’re well insulated and further mechanically protected by the outer sheath of the cable type. As said, you need slack to install them, and likewise for downstream service / repair. Stand down red alert afaic 👍 Link to comment Share on other sites More sharing options...
Conor Posted October 14, 2022 Share Posted October 14, 2022 There has to be some slack or else you couldn't drop the panels or or remove them, each one is a good metre long. I looped up and excess slack but left enough so you could flip a panel up 90° in situ and access the connectors. And the MC4 connectors are well tough. Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 14, 2022 Share Posted October 14, 2022 Unless you specified conduit / other, which you’d have paid for, the norm / knee-jerk is what you have. Fwiw I won’t be doing anything more on my own install. Link to comment Share on other sites More sharing options...
Dillsue Posted October 14, 2022 Share Posted October 14, 2022 Panel cables are just loose on the MCS installed system we have and on the diy systems weve put in this year. Its possible to do a bit of tidying and cable tying as each panel goes in BUT..... If you want to remove a panel in the centre of a row for repair/replacement and youve tie wrapped all the slack into loops, its gonna be a twat of a job to lift anything but the perimeter panels Link to comment Share on other sites More sharing options...
Radian Posted October 14, 2022 Author Share Posted October 14, 2022 1 hour ago, Nickfromwales said: Stand down red alert afaic 👍 Just checking. Like you do when you're not sure. The subject of loose cables has come up before on electriciansforums.net and the general consensus seemed to be that they should be secured to prevent them rubbing on the roof. But that was 10 years ago so maybe practice has changed to be more pragmatic since then. Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 14, 2022 Share Posted October 14, 2022 You need a minimum of 600-800mm of slack just to install the panel. When the panel is down, that slack cannot practically be anchored. Move on to the next item, this ones fine afaic. Link to comment Share on other sites More sharing options...
Radian Posted October 14, 2022 Author Share Posted October 14, 2022 7 minutes ago, Nickfromwales said: Move on to the next item, this ones fine afaic. How on earth did you know there was more to complain about? 🤣 Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 14, 2022 Share Posted October 14, 2022 Just now, Radian said: How on earth did you know there was more to complain about? 🤣 90% done, only 90% left to do…… Link to comment Share on other sites More sharing options...
Radian Posted October 21, 2022 Author Share Posted October 21, 2022 OK, this one's rather awkward. Bear in mind that I only want an easy life, and that the installation co. are bending over backwards to keep me happy. The array performs well but it bothers me every time I look up at it from the path below. The modules are in landscape so the mounting rails sit directly on top of the rafters - which, at 175mm deep, are pretty darn straight. Yet the rail on the outside edge of the array is a bit of a rollercoaster at the top and the modules follow the bends: Now I get that there's no such thing as perfection and function-wise everything's fine. But this is the view we get every time we walk around the corner of the building and glance up. What I just don't get is how the roof hooks which are screwed onto the rafter could end up at different heights. To try and quantify the amount of deviation I got up on a stepladder and shone a laser plane at the side of the rail: The green laser wouldn't reflect off the side of the rail or modules but showed up OK around the vertical face of each roof hook where it meets the bottom of the rail. At least it did on the lowest two. looking up at the top two you can see it hits the bracket about half way up. That's about 25mm out of line. So what should be my expectations be here? I wouldn't expect it to be deviating from the rafters at all. It just seems as though something's wrong up there. If you could stand back from the roof I'm sure it'd look fine but its 1.5m away from our boundary so we only ever see it from close-up below. I showed the installer these photos and he is willing to return and strip off the first column and inspect the mountings but I don't want to put him to the trouble if people here think it's really no worse than they'd expect. So thought please... Link to comment Share on other sites More sharing options...
Dillsue Posted October 22, 2022 Share Posted October 22, 2022 Arent the roof hook to rail connections adjustable? This may allow someone to reach in from the side and raise the rail where it dips?? Certainly Renusol rails are straight when they dont have a load so its pretty hard to install them bowed unless its at the joint of 2 sections. Im not one for creating unnecessary work so if it can be lifted from a ladder crack on, otherwise get the installer back as it should be straight to the casual glance. Link to comment Share on other sites More sharing options...
Radian Posted October 22, 2022 Author Share Posted October 22, 2022 41 minutes ago, Dillsue said: Arent the roof hook to rail connections adjustable? No, they bolt down straight on top of the flat. The hooks are solarflash from geniusroofsolutions If I had been doing it, I'd have treated it like any other job where you're placing things in-line, like fence posts or shelf brackets, and used a laser or simply a string line to make sure everything lines up. But I can't understand how we ended up about 25mm out of line when four of these were attached to the same rafter (geniusroofsolutions own photo is a bit odd as it seems to be vertical slate cladding but at least it shows the bracket we've got): Link to comment Share on other sites More sharing options...
billt Posted October 22, 2022 Share Posted October 22, 2022 Having installed similar brackets I can say that roof timbers aren't precision made and you will get height variation. My brackets could have the height adjusted slightly by controlling the torque on the fixing screws. Tighten the back one and the front rises, tighten the front one and it falls, but that's only a very small adjustment. For anything more than that I used packers between the bracket and the rail. Unfortunately it's a bit time consuming if there are several that need adjusting. Link to comment Share on other sites More sharing options...
Radian Posted October 22, 2022 Author Share Posted October 22, 2022 I've just clocked that the brackets themselves may differ from the ones in the above photo. geniusroofsolutions don't actually provide the brackets (hooks), just the flashing kit that goes around them. So I can't say for sure what the bracket looks like. 39 minutes ago, billt said: Having installed similar brackets I can say that roof timbers aren't precision made and you will get height variation These were recently manufactured chunky attic trusses so I wouldn't expect them to be this much out of true. Having said that, I would expect the greatest deflection under roof load to be acting somewhere between the collar and wall plate. Based on that, I can see how the shape the rail has taken might have come about simply by following the natural deflection. It could be that the lower two brackets need shims between them and the rails. Again, a simple string line would reveal the 'truth'. Link to comment Share on other sites More sharing options...
Dillsue Posted October 22, 2022 Share Posted October 22, 2022 Plenty of sagging roofs around so very naive of the mounting system designer not to have included a means of fitting straight rails, if thats the case. Lining up the rails takes time so maybe they rushed things and left out packers or slotted angle brackets?? If your roof was sagging, and that was the cause, youd be able to see the panels/rails running parallel to the roof but in one of the pictures the roof looks to be straight?? Link to comment Share on other sites More sharing options...
Radian Posted October 22, 2022 Author Share Posted October 22, 2022 46 minutes ago, Dillsue said: If your roof was sagging, and that was the cause, youd be able to see the panels/rails running parallel to the roof but in one of the pictures the roof looks to be straight?? Yes the roof looks perfectly straight to me. When I zoom in on the photo in the OP of this topic I can see the bottom of the top two hooks, where they enter the flashing hoods, appear to bend up and away from the slates. These are the two that the laser line meets half way up so suggesting that these two push the rail up (rather than the bottom two being too low) If this is the case then the hooks are either bent up or aren't sitting flat on the rafter. Link to comment Share on other sites More sharing options...
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