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Wires through roof


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A stupid question, but is there a good way of taking your wires from solar panels through the roof?

As I understand regulations it can not be just through a hole because that can damage the wires  (Google showed some overseas products but nothing in SA that Icould find)
Will something like this be OK? 1545.11.07,1545.11.10.jpg

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46 minutes ago, Otto ES said:

Will something like this be OK?

If you are going through roof tiles I think this gland will not work because its thread is to short to catch on the tile.

I personally prefer a galvanised conduit for going through the roof tiles and siliconed and saddled for sturdiness. The conduit can than also be earthed to your earthing system for extra protection.

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4 hours ago, Gerrie said:

If you are going through roof tiles I think this gland will not work because its thread is to short to catch on the tile.

That cable gland is also (most likely) not UV-resistant.

I see a few sellers selling the dektite aluminium flashing. Sustainable has it for around R700 (a tad steep), also look on bidorbuy, or just google it. No idea how good a product it is, but looks similar to what is available internationally.

 

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Yes Gerrie, you are right, that is not going to work. I will look at the galvanised conduit. Must just figure out how to connect it to the tray or channel in the roof.
Thanks plonkster. I did not find these in my search. While expensive as you say they will surely work!

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8 hours ago, plonkster said:

I see a few sellers selling the dektite aluminium flashing. Sustainable has it for around R700

In case someone else is trying to do the same: there are different models and options which can vary quite a lot in price. The Dektite Aluminium Multicable Solar Flashing (Metal Roof ) is quite affordable if it fits your purpose (less than R150). 

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11 hours ago, Otto ES said:

Must just figure out how to connect it to the tray or channel in the roof.

On my own installation I just went straight through the roof with a  armoured cable. I drilled a 25mm hole through the roof tile, pushed cable through, than glanded the cable in the ceiling to another junction box inside the ceiling, from there I have a long run to my garrage. (about 20mtrs but used 4mm2 gp wire doubled up and inside, partial galvanized, partial pvc conduit)

At the roof tile hole, I just used lot of silicone and straped the cable to prevent movement. According to me this method is ok because the armoured cable has its own mechanical protection. 

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Something I have seen done in ANY areas that an get damaged via abrasion, crimping, etc: Use a short piece of cable with connectors each side that goes through the area likely to be damaged. This short piece can then be replaced without major cost/time impact on installation when ness.

As an example: I use this method for ANY cable that runs from the inside to outside my Camper Van. It breaks, it is quick and simple and cheap to fix.

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52 minutes ago, Gerrie said:

Do you know which regulation that is?

Oh dear... that is actually true. Section 5.3.5.2 (which concerns earthing):

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Where conduit is used for DC cables, it shall be metal conduit. Conduit shall be bonded at all junctions to ensure electrical continuity of the conduit. The metal conduit shall be bonded to earth at a suitable location.

Also 6.2.8:

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Where a system features DC cables longer than 50m, the cables shall be installed in earthed metal conduit or using armoured cable.

So the loophole seems to be... if you are not using conduit for <50m lengths (trunking?)... then it doesn't have to be metal.

 

3 hours ago, Clint said:

Aluminium ok or not

Apparently Aluminium would be okay then, since it is a "metal". Searching the SANS document for "steel" yields no useful info, but "metal" yields plenty 🙂

 

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6 hours ago, plonkster said:

Oh dear... that is actually true. Section 5.3.5.2 (which concerns earthing):

Ah!! thanks plonkster, Now I see proof is’s never to late for me to learn.

 

6 hours ago, plonkster said:

Where conduit is used for DC cables, it shall be metal conduit.

This is new to me, or I geuss I never read that portion 😬 luckily I used armoured cable from roof to a pvc junction box that’s in the roof, from there I used a 32mm  bosal conduit to my garage to another  pvc junction box. From here I have a steel trunking with plastic lid to my combiner DB I did bond all conduits and bends with 4mm earth straps. (I geuss my installation is ok but I do need to remove some other wire out of the bosal like my keypad comms wire and even my inverter ac supply cable is in there, I’m still searching for that loophole🤫)

I think it will be the cheapest to just run a armoured cable straight to inverter DB to pv panels, because bosal conduit is not cheap and is lots of labour.

6 hours ago, plonkster said:

So the loophole seems to be... if you are not using conduit for <50m lengths (trunking?)... then it doesn't have to be metal.

This is one of those regulations written to cause one big debate. 😁

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23 minutes ago, Gerrie said:

This is one of those regulations written to cause one big debate. 😁

I suspect this is about EMC. The regulation says it must be on conduit, the conduit must be bonded at the junctions (ie a clamp on either side with some copper to make sure you have a good connection across the coupling), and then the entire length must be earthed at some convenient point. IE... it's creating a massive shielding for the PV wires.

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Good morning all. To which code are you referring to? Also, would it be possible to post a list of codes, standards and legislation one needs to follow shoul you wish to install a solar setup?

I think a list of the above, compiled by the informed members on the forum, would be very valuable. I wish I could help but my knowledge stops at red = + and black = -. 😉

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Reading the SANS doc is a real mission, it makes for very difficult reading, x refers to Y , Y to Z etc., etc, one would think that the engineering types would have created a decent doc that provides a "click" to x and Y to make it easier to get to the bottom of what is required...They should get the IT guys to make a plan😬

 

Ok, so we have the first requirement;

1) Its either armoured cable or steel conduit, no PVC

2) All Panel mountings must be grounded to earth spikes at least 3 of 1.2m long with a 8mm min diameter of earthing cable (NOT the DB board) (This needs to be checked, confirmed, this is the one item I was actually looking for when I found the PVC item).

3) Inverter grounded to DB board.

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4 hours ago, plonkster said:

I suspect this is about EMC

That is probably what I experienced a few months back my kids told me the shower tap shocked them, I said now ways everything is earthed. But than after a test I felt the shock, for me it wasn’t to bad my resistance is higher than the kids but I than felt it.

I than added lots of more earthing over a period of about a month. I added lots of bonding even extra spike directly to my geyser and a spike on my pv panel side and another spike on inverter side, I don’t know which earth was the one that solved the shocking problem but it eventually came right. 

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12 hours ago, Corné said:

Good morning all. To which code are you referring to?

It looks like SANS 10142-1-2 for EGI installations, but than this only apply to grid tie installations as per reg 6.3 if you are off grid it seems you need to comply with the normal SANS 10142-1

 

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On 2020/02/25 at 11:29 AM, Gerrie said:

That is probably what I experienced a few months back my kids told me the shower tap shocked them, I said now ways everything is earthed. But than after a test I felt the shock, for me it wasn’t to bad my resistance is higher than the kids but I than felt it.

I than added lots of more earthing over a period of about a month. I added lots of bonding even extra spike directly to my geyser and a spike on my pv panel side and another spike on inverter side, I don’t know which earth was the one that solved the shocking problem but it eventually came right. 

Hi Gerrie

I also had that problem in my house.

It turned out that the municipal common wire was stolen from the power lines outside.

I would be concerned that you are leaking electricity into the ground somewhere.(I hope this makes sense)

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On 2020/02/24 at 11:31 PM, plonkster said:

Where conduit is used for DC cables, it shall be metal conduit. Conduit shall be bonded at all junctions to ensure electrical continuity of the conduit. The metal conduit shall be bonded to earth at a suitable location.

Does "Where conduit is used" imply that it is only applicable when you use conduit?  Can you use pvc trunking? 
In reality most installations that I have seen uses trunking around the inverters and DB's. Is this illegal?

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1 hour ago, Otto ES said:

Does "Where conduit is used" imply that it is only applicable when you use conduit?  Can you use pvc trunking? 

I'm not an electrician, but if I understand it correctly, it says that for long distances you must use conduit (ie, for shorter distances it might be optional), and where conduit is used it must be earthed in the prescribe manner. That would seem to imply that for shorter distances something else can be used. What that something  else is is not specified.

PVC trunking is of course not water tight nor UV resistant, so can't really be used unless its inside.

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1 hour ago, Corné said:

Good day Everyone

@plonkster, what is the name/code of the standard you are referring to here? I must be missing something?

SANS 10142-1, the 2017 edition. Of which I got a draft copy (not the final one).... because it costs money to get the official one 🙂

 

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