Neutral/earth bond Sans 10142

[Derlyn]

I have looked and found the reg stating that the neutral shall not be earthed beyond an earth leakage relay.

Where in Sans does it state that the neutral shall not be earthed on the load side of the point of control ?

Cannot find it. Help please. I have a dispute.

[GCE]

These are the clauses that are relevant to your question



From SANS 10142-1 ed3.2
6.1.6 The neutral conductor shall not be connected direct to earth or to the
earth continuity conductor on the load side of the point of control except as
allowed in 7.16.4

7.12.3.1.3 Where alternative supplies are installed remotely from the
installation, or from one another, and where it is not possible to make use of
a single neutral bar or neutral conductor which is earthed, the neutral of each
unit shall be earthed at the unit and these points shall be bonded to the
consumer's earth terminal (see 6.12.4). The supply from each unit which
supplies the installation or part of the installation, shall be switched by means
of a switch that breaks all live conductors operating substantially together
(see figures P.2 and P.4), to disconnect the earthed neutral point from the
installation neutral when the alternative supply is not connected (see also
6.1.6).



Under Distribution systems
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.

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

[Derlyn]

@GCE. Thank you, my brother. Much appreciated.

That should settle my dispute convincingly. 👍👍👍

[GCE]

And then we have NERSA requirements which the naysayers will tell you is not a regulation but it is a requirement for utilities to adhere to as good practice
Utilities will generally insist on the below

Extract from NRS 097-2-1:2024

5.4 Neutral to earth bonding when forming an intentional island
5.4.1 To prevent a SSEG neutral connection to the the utility neutral through an earth conductor when the SDU opens, the SSEG shall not have a permanent neutral bonding to earth.
5.4.2 A hybrid system intended to form an intentional island on the load side during utility supply interruption shall open the SDU to prevent unintentional island on the utility side.
5.4.3 Since the SDU opens the neutral on the utility side, the intentional island neutral shall be bonded to earth within 200 ms after the SDU operation using a neutral to earth bonding unit (NEB).
5.4.4 The NEB shall open within a time period of 200 ms before the SDU reconnects the inverter to the utility supply.
5.4.5 The NEB shall consist of an electromechanical switching device rated at the nominal current rating of the inverter.
5.4.6 The total clearance between the inverter neutral and earth conductors when the NEB is switched off, shall be equal the clearance of the SDU in its open state or more.
5.4.7 The NEB shall be an internal inverter component or an external device that is activated by a dedicated control port of the inverter.
5.4.8 The inverter data sheets shall indicate that it contains an internal NEB or a dedicated NEB control port for external devices.
5.4.9 Installation requirement: Inverters equipped with the NEB control port only, shall have external electromechanical NEBs installed that are SANS/IEC 60947-1 and SANS/IEC 60947-4-1 certified.

[GCE]

Then you often bump heads about point of control and point of supply

A person you supplies his own electricity is a consumer , not a supplier and therefore the solar system does not have its own point of control as recognized by the regulations


Definitions from SANS 10142-1
3.56
point of control
point at which a consumer can, on or in any premises, switch off the electrical
installation from the electricity supplied from the point of supply

3.58
point of supply
point at which a supplier supplies electricity to any premises

3.77
supplier
in relation to a particular installation, any local authority (see 3.47), statutory
body or person who supplies, contracts or agrees to supply, electricity to that
electrical installation

3.16
consumer
person who is supplied (or who is to be supplied) with electricity by a supplier
(see 3.77); or a person who supplies his own electricity

[Derlyn]

Wow! Have I got sufficient ammunition now, or what. 🤣👍👍

[Derlyn]

Thank you GCE. Dispute settled thanks to that ammo. At least there are another couple of guys that have been converted to doing it the right way. 👍👍👍

[Leonsparky]

@Derlyn, if a bond is installed past the earth leakage it will constantly trip. So it cannot be installed there.

There references of 7.12.3.1.3 as (as stated above by GCE) specifically refers to alternative supply as a switched alternative. This sections says neutral SHALL be bonded to EARTH. It refers then that live conductors will disconnect substantially together with the NEB. This is done with a change over switch.
I am taking a wild guess that you are referring to the relay that should make the bond? this section definitely does not say use a relay, and your live conductors (Live and Neutral) shall disconnect at the same time as the NEB.

As the inverter is a supply, you have essentially created another point of control. @GCE, please refer to the EIR for the definition. It is another section of an installation because your point of control - main switch - supply from eskom has a main switch which disconnects a part of the installation and anothr point of control that switches off the loads under the secondary supply.


The next section of reference mentioned by GCE is also distribution networks which does not apply to houses. a distribution network is a reticulation system. A TN-S system is 3 wire system. TNC is a 2 wire system. in no way are you creating a tnc if you bond neutral and earth. this is called a TN-C-S.



We further move on to NRS specifications
Yes it is not a requirement to comply, because it is not a SANS standard, it is a document for the supplier and its workers, not the general public.
This is also for parallel systems (grid tie).

We have made quite a lot of progress and have done a few tests with the NRS to come to a conclusion.
Under no circumstance are you allowed to connect a neutral earth bond through a relay. This connection must be done permanently if it is not done internally of the inverter.