How do you put a conduit through a corrugated iron roof in the neatest way possible? In my case, it's a carport, so I'm not worried so much about a tiny leak or two, but I do want it to look neat. Do you just drill a 20mm hole and silicon it tight? That feels hacky.

Looking forward to your advices :-)

It always worked for me.....

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@plonkster depending on the pitch of the roof I used a step drill to drill to exact size (20mm) and then used a 20mm rod to "bend" the whole into the right direction when you insert the conduit it will have a "flush" finish will be as good as anything. Alternatively you can look at something like this: 
https://hydroponic.co.za/hydroponics/grommets/

Should give the desired professional look.

Roof heat and sunlight is always a issue with rubber I found. I made a hole in the roof sheets and used roof products to seal the pipe, then I covered it all to get it out of the sunlight.

5 minutes ago, The Terrible Triplett said:

sunlight

Yup, that is my concern too. If it's not UV resistant, the sun will kill it. Conduit itself eventually goes brittle, but it takes many years before it gets there, so I am not too worried about that. The conduit will be in the shade of the panels too.

Come to think of it, I'm going to need something to drill a 20mm hole with. I think the biggest steel drill I own only goes up to about 12 :-)

Make sure you drill the hole through the top of a corrugation, not the bottom where the water runs.

19 minutes ago, DeepBass9 said:

Make sure you drill the hole through the top of a corrugation, not the bottom where the water runs.

Ja, that is some VERY appropriate advice ... wish someone told me that before the arse drilled the hole in the valley instead of the top.  

Use a 20mm hole saw that you can buy at Builders to drill through the sheet. To seal around the conduit I use Dektite from Kare industrial suppliers, they are on the corner of Vootrekker and Vanguard Dr in Maitland.

39 minutes ago, The Terrible Triplett said:

Ja, that is some VERY appropriate advice ... wish someone told me that before the arse drilled the hole in the valley instead of the top.  

I know. I made that mistake only once, way back in the day on the farm in Namibia. Dad came walking past and saw where I drilled the hole and the disappointment was palpable. Of course, given the weather, it hasn't rusted yet! (20 years later)... but the memory has remained.

33 minutes ago, DownTime said:

Dektite from Kare industrial suppliers, they are on the corner of Vootrekker and Vanguard Dr in Maitland.

Way too far to drive just for that :-) Maybe a local store has something similar, thanks.

8 minutes ago, plonkster said:

Way too far to drive just for that :-) Maybe a local store has something similar, thanks

Then try using WURTH's bond and seal around the hole when the conduit is in, it lasts much longer then normal silicone.  I inspected some installations I did 7 years ago with bond and seal and no leaks at all.

Hey check it out, these guys we never buy from has it... :-)

1 hour ago, The Terrible Triplett said:

Ja, that is some VERY appropriate advice ... wish someone told me that before the arse drilled the hole in the valley instead of the top.  

Its perfectly obvious once you have done it wrong once! Don't ask how I know that...

32 minutes ago, DeepBass9 said:

Don't ask how I know that...

Plus one and Amen to that. 

Sometimes some posts in this forum makes my day...  

Don't drill through the roof, run the pipe "around" the roof with some 90deg elbows. 

21 hours ago, SilverNodashi said:

Don't drill through the roof, run the pipe "around" the roof with some 90deg elbows. 

Indeed, I googled into that answer too and it would be the preferred answer. So on the one side I have an electric fence. Don't really want to run my PV right next to the fence wire. On the other side I have a wall, and due to the way that is constructed, I can't come out of the wall high enough to be above the roof. The third side has a gutter, going around that at right angles is going to look very odd. That leaves the back side, which, though feasible, doubles the total distance from 10 meters to 20. It's a car port, so how it looks and whether it rusts are the main concerns, not so much whether it is completely water tight.

I therefore opted to go through the sheet metal with a hole saw, because I already had the hole saw. I was concerned it wouldn't be up to the challenge of cutting metal, but it worked just fine.I then had the conduit run straight through into a junction box screwed onto the beam below so it is supported from below. Now I'll just seal it around the hole and we should be good to go. I now also have the conduit entirely in the shade until it pops up right under the panels.

if you have to, get a big enough cable/compression gland. speaking of,  I found these OBO ones to be really nice quality. http://www.obo.com.cn/userfiles/V-TEC VM cable glands_en.pdf

10 minutes ago, Weasel said:

if you have to, get a big enough cable/compression gland. speaking of,  I found these OBO ones to be really nice quality. http://www.obo.com.cn/userfiles/V-TEC VM cable glands_en.pdf

 

Mind you to do it right the hole needs to be nice and round and the right size else it will leak, a step drill will cost you more than one of those deklite flashings. 

11 hours ago, plonkster said:

Now I'll just seal it around the hole and we should be good to go.

Sikaflex instead of silicone. 

11 hours ago, Weasel said:

a step drill will cost you more than one of those deklite flashings

Yup, I already looked for one yesterday and decided to try the hole-saw instead. The hole is perfectly round, and because it's on the ridge and not in the valley and it's a carport and not the roof of the house, a silicon/sikaflex/mastic seal will do the job. I was also concerned that the conduit would be loose and disturb whatever seal I do try to put in, but this is sorted now.

 I found a supplier in Durban https://kareindustrial.co.za/  Dektite pipe flashing.