Lightning protection and/or bonding

[Isetech]

What is the purpose of this thread (in fact all my posts)? firstly it is not a pissing contest, it is an attempt to get the facts correct.

Lets get it right, it not about us, its is about public safety.

Now that we have that out the way.

When do you install lightning protection and when is only bonding or earthing required, is there a difference between lightning protection, bonding and earthing?


6.13 Bonding
NOTE 1 The aim of bonding is to bring all the bonded parts to the same electrical
potential.
NOTE 2 No external conductor is required if compliance with the requirements for
continuity can be proved by the test in 8.6.2.


8.6.2 Continuity of bonding
Confirm the continuity of the bonding conductors between all exposed
conductive parts within arms reach (or see annex A) of each other. When a
test device or instrument is used, it shall have a supply that has a no‐load d.c.
or a.c. voltage of 4 V to 24 V, and a current of at least 0,2 A. In each case, the
resistance shall not exceed 0,2 Ω.


6.13.1 Bonding conductors
A bonding conductor shall
a) have a nominal cross-sectional area of at least 2,5 mm2
copper or
equivalent, and
b) be so arranged that it cannot be tampered with.

[Isetech]

1.3 Where this part of SANS 10142 is not applicable

g) external lightning protection of buildings and structures as it is covered by
SANS 10313,



6.7.6 Surge protection

6.7.6.1
Surge protective devices (SPDs) may be installed to protect an
installation against transient overvoltages and surge currents such as those
due to switching operations or those induced by atmospheric discharges
(lightning).

NOTE A risk assessment may be performed in accordance with annex Q.
The Installation of SPDs is necessary where structures are equipped with
external lightning protection systems (LPS) as in accordance with
SANS 10313.

6.7.6.2
Where SPDs are to be installed in low-voltage installations, their
selection, connection and application shall be in accordance with
SANS 61643-11, SANS 61643-12 and annex I.

NOTE SPDs installed for lightning protection will automatically cover switching surges.

6.7.7
External lightning protection
NOTE Where external lightning protection is installed, it should be in accordance with
the requirements of SANS 10313.

[Isetech]

The question I hear being asked, if you install solar panels, do you have to install lightning protection, surge protection and bonding and do you link them all together?

Is it a good idea to link the frame of your class II device (solar panel) directly to your external lightning protection, are you not doing this by installing a 16 mm earth wire directly to an earth spike in the ground, which would now require class I surge protection and class II surge protection?

[Isetech]

Reading up about large solar installations, in many cases, external lighting protection is required to protect the anodized frame of the solar panel/PV module from being hit by lightning.

The next question would be, was a lightning assessment done at the same time the roof assessment and the safe battery location assessment was done ?

If the location was deemed a high lightning risk, surely you would have to then start looking at a proper external lightning protection arrangement, class 1 SPD's and certainly not link it to the frame of the aluminum frame of the panel.

How would you do it in a situation where there is a risk of lightning strikes, just link the panel bonding conductor directly to the 25 mm lightning conductor installed around the roof ?

Do you install a separate spike for the backup system and a a separate spike for the external lightning arrangement?

Too many question for a Sunday

[Isetech]

Every single solar installation that I have visited, has 3 wires from the roof red/black and green/yellow into a PVC 20 or 25 mm pipe down to the DC control box, from the DC control box to the AC control box, then from the AC control box to an earth spike knocked in the ground close to the building.

They say just because everyone is doing it, doesnt mean it is right.

So who can tell us what is the right way to do it, the DOL, the ECA, the ECA, SAPVIA, SSESA, AREP.

There seems to be this confusion that every electrician/installer must know the regulations, I agree, but we DONT make the regulations. When someone comes up with the correct regulations please let us know, and stop confusing everyone with a bunch of different people tell everyone what they feel is the right way to do it. It shouldnt be a trick question, nor should a percentage of people do it one way another percentage do it another way and other percentages do it their way.

We seem to loose focus on the goal...PUBLIC SAFETY.

The aim of this part of SANS 10142 is to ensure that people, animals and
property are protected from hazards that can arise from the operation of an
electrical installation under both normal and fault conditions. An electrical
installation has to provide protection against:
– shock current,
– overcurrent,
– fault current,
– overvoltage,
– undervoltage,
– excessive temperatures, and
– electric arcs.


This South African standard was prepared by National Committee
SABS/TC 067/SC 06, Electricity distribution systems and components –
Installations, in accordance with procedures of the South African Bureau of
Standards, in compliance with annex 3 of the WTO/TBT agreement.
This document was approved for publication in xxxxx 2021.
This document supersedes SANS 10142-1:2020 (edition 3)

Start enforcing refresher courses relevant to the electrical field the electrician works in, in other words if you are an MIE and work in the pharmaceutical industry, then you should have to prove you have attended courses relevant to that filed, which will keep you up to date with amendments to the regulations.

[Isetech]

Before I continue with this thread, 2 things need to be addressed before you start applying any method/s which might not be relative to your supply nor your installation.

1/ Lighting protection, have you carried out a risk assessment ?

As you are continuously reminded, read the regs :

NOTE A risk assessment may be performed in accordance with annex Q

If you decide to do a risk assessment make sure you apply all the regulations, including class 1 surge protection. You cant half apply the regulations, you either install external lightning protection or you dont.

2/ Type of supply.

This is where I believe 99 percent of the confusion is happening, social media is all around the world, not just in your specific area.

Do you understand enough about electricity to know which earthing arrangement is feeding the property where you are working.

[Isetech]

Lets discuss earthing arrangements and why it is so critical to know which arrangement applies to the electrical installation where you are working.

The neutral earth bond, until we get to the bottom of this or someone is seriously injured, people will just keep doing what they think is right.

What are the different arrangement:

TN-C

TN-S

TN-C-S

TT

IT

At no point on any installation should these types of earthing arrangements be mixed.

Before you rush out and apply a method discussed on a social media platform which might not be relevant to your installation, which could create a really dangerous installation, take note.

Something else to point out, at no point under "normal" operation should you ever have current flowing on the earth wire, Some one mentioned that it had something to do with the internal electronics, then it should be managed within the device, not floating around outside the device, dont you agree ?

Just so that we are on the same page, the earthing arrangement in our part of the world is a TN-S.

7.12.3 Earthing requirements and earth leakage protection

7.12.3.1 Neutral bar earthing

7.12.3.1.1 Protection in accordance with the requirements of 6.7 shall be
provided for the electrical installation in such a manner as to ensure correct
operation of the protection devices, irrespective of the source of supply or
combination of sources of supply. Operation of the protection devices shall
not rely upon the connection to the earthed point of the main supply when the
generator is operated as a switched alternative to the main supply.
Where there is no existing earth electrode installed in the electrical installation,
a suitable earth electrode may be installed in accordance with SANS 10199.
When installed, the electrode shall be bonded to the consumer's earth terminal
and to the earthing point on the alternate supply by a conductor of at least half
the cross-section of that of the phase conductor, but not less than 6 mm2
copper, or equivalent. This also applies to a single-phase supply
(see also 5.2.3.1).
NOTE 1 In a TN system earthing of electricity supply, an earth electrode is normally
not required in an electrical installation.
NOTE 2 Protection of photovoltaics can be by means of or surge protective device
(SPD).



7.16.4 Neutral earthing

7.16.4.1 Whereas TN-C systems may be implemented along the distribution
system backbone, the individual service connections at every distribution
kiosk shall be TN-S.

7.16.4.2 From the point of supply to each user or part of a communal
installation, the neutral and earth conductors shall be separate conductors.

7.16.4.3 Wherever the neutral is connected to the earth, a warning notice
shall be fitted to the outside of each distribution kiosk in the distribution
system, indicating "Neutral earthed inside".

7.16.4.4 A clear notice shall be fitted at the combined neutral-earth
connection inside each distribution kiosk in the distribution system, that
prohibits the removal of this connection while the supply is alive, or might
become alive.

7.16.4.5 The neutral shall not be earthed beyond any earth leakage unit.

7.16.4.6 A TN-S system shall not be converted to a TN-C system.


The way I understand it, and by the way I might be way off the mark, so feel free to correct me if you know better, I am trying to wrap my head around it.

You cannot link a TN-C and TN-S arrangement at any point of a individual service.

You have an inverter installed on the property which is a class II device, and this is where the confusion originates, the power goes through the inverter, the output is still the from the grid supply, therefore the earthing arrangement must be separated from the inverter power supply. What this means, if you test the voltage on the input of the inverter and the voltage on the output, it is exactly the same.

An inverter is "not" and inline/online UPS, it switch over to inverter power once the grid power is lost.

This is where the confusion with neutral bonding is the problem. Once the inverter power switches OFF, the inverter will then go into ISLANDING MODE, which from my understanding means the inverter is completely separated from the GRID TN-S earthing arrangement, which is why you have to at that point create A TN-C as close to the inverter as close to the inverter as practically possible and at no other point in the installation. And you need to install and earth spike/electrode in case the grid earth is lost.

[Isetech]

12.534.4.4.101.2 Selection of SPD test class


Generally SPDs will be class II test. If protection against effects of direct lightning strokes is
specified and separation distance S is not kept in accordance with IEC 62305 (all parts), class
I test SPDs shall be used (generally in conjunction with class II test SPDs).

[Isetech]

Is creating a really good low resistance earth bond such a good idea?

How would you make sure that your earth is not better than the grid earth, does it really matter?

Some many questions.