Hi All,

 

Hope you all are doing well,

Please can you help me with 3 questions I have?

I currently have a 16mm flat twin + earth cable running from my house to an outside building, spanning about 4.5 meters, and about 2.5m overhead above ground. It runs in a PVC conduit.

The conduit and cable does not sag, as they have been run through a larger aluminium pipe which is fixed between house and the carport.

 

1. I want to know if this meets the SANS requirements for outdoor wiring please? I tried looking for this info however I was not successful.

 

2. If the answer to question 1 is Yes, then I would like to run a second 16mm flat twin + earth cable in a seperate PVC conduit fixed to the first one. I will then use both these cables to connect an Inverter. From what I understand, I would need to run a seperate Earth wire to and from the inverter, as the one included in the Flat twin + earth cable is not large enough. Should I be using a 16mm Earth wire for this? Also, do i also use the earth wire in the flat twin + earth cable or do i cut it short.

 

3. Regarding solar panel grounding, which size cable should be used? Also, can this be solar wire (6mm), or do I need to use green/yellow GP wire?

 

Thank you all for your expert advise

 

 

 

 

Edited August 21, 20242 yr by faultydaveza
added the word "overhead"

1 hour ago, faultydaveza said:

Hi All,

 

Hope you all are doing well,

Please can you help me with 3 questions I have?

I currently have a 16mm flat twin + earth cable running from my house to an outside building, spanning about 4.5 meters, and about 2.5m overhead above ground. It runs in a PVC conduit.

The conduit and cable does not sag, as they have been run through a larger aluminium pipe which is fixed between house and the carport.

 

1. I want to know if this meets the SANS requirements for outdoor wiring please? I tried looking for this info however I was not successful.

 

2. If the answer to question 1 is Yes, then I would like to run a second 16mm flat twin + earth cable in a seperate PVC conduit fixed to the first one. I will then use both these cables to connect an Inverter. From what I understand, I would need to run a seperate Earth wire to and from the inverter, as the one included in the Flat twin + earth cable is not large enough. Should I be using a 16mm Earth wire for this? Also, do i also use the earth wire in the flat twin + earth cable or do i cut it short.

 

3. Regarding solar panel grounding, which size cable should be used? Also, can this be solar wire (6mm), or do I need to use green/yellow GP wire?

 

Thank you all for your expert advise

 

 

 

 

1.   I see no problem but let's await a reply from @TaliaB

2.   As long as the earth wire is 6mm² for each 16mm² phase and N conductor. 

3.   I would use bare copper earth wire. If it is insulated it has to be green/yellow AFAIK. 

Thank you Scorp for your reply!

1. Ok thanks

2. Oh that's great news, that saves me some time and money

3. That makes sense, thank you

9 hours ago, faultydaveza said:

The conduit and cable does not sag, as they have been run through a larger aluminium pipe which is fixed between house and the carport.

 

1. I want to know if this meets the SANS requirements for outdoor wiring please? I tried looking for this info however I was not successful.

1. For above question no problem it runs in pvc conduit within aluminium pipe so acceptable within Sans regulation. Normally for outdoor use round Surfix or Norsk is used as the inner core insulation is UV protected due to extra insulation layers but in your case it is adequate.(conduit and aluminium pipe)

2. 16mm² flat or round Surfix has a earth conductor of 6mm² that is adequate up to 60A. As the cable is rated for 87A above 60 Amps a seperate bare 6mm² copper earth conductor should be run  with the cables connected to the Surfix earth( paralleled).

3. I normally run 10mm² green/yellow Gp earth conductor connected to frame of panels to ground rod.

@faultydaveza @Scorp007

 

Edited August 21, 20242 yr by TaliaB

Hi @TaliaB,

 

Thanks very much for the answer, i really appreciate it.

 

So for question 2, For now I'll be using 32A MCBs for this 16mm² cable, but should I upgrade the inverter in future, and I stick to lets say a 50A MCB, then I wouldn't require the extra earth conductor? Or do I need the extra conductor solely on the fact that the cable is capable of more than 60A?

 

Thanks again

1 hour ago, faultydaveza said:

Hi @TaliaB,

 

Thanks very much for the answer, i really appreciate it.

 

So for question 2, For now I'll be using 32A MCBs for this 16mm² cable, but should I upgrade the inverter in future, and I stick to lets say a 50A MCB, then I wouldn't require the extra earth conductor? Or do I need the extra conductor solely on the fact that the cable is capable of more than 60A?

 

Thanks again

2. No if you are using 32A the 6mm² earh cable in the Surfix is good but should you in future exceed the 60 amps you need the additional 6mm² earth conductor. Any current draw below 60A the 6mm² earth wire would suffice.

Edited August 21, 20242 yr by TaliaB

Awesome thank you very much @TaliaB

Hi there,

From what you’ve described, your setup looks well done since the conduit and cable are properly supported by the aluminium pipe without any sagging. For outdoor wiring, SANS standards require cables that are UV-resistant and protected from weather and physical damage. If your PVC conduit is rated for outdoor use, then it should be acceptable. When you add the second 16mm flat twin and earth cable for the inverter, using a separate PVC conduit as you mentioned is the right approach. The earth wire in the flat twin and earth cable is not large enough for the inverter, so running a separate 16mm earth wire is the correct option. Keep the existing earth wire connected as it still provides bonding for the circuit. For grounding the solar panels, a 6mm cable is generally suitable, but it should be a proper green and yellow earth wire instead of regular solar cable to meet safety and grounding requirements.

Edited October 29, 2025Oct 29 by brook