Neutral earth bonding on backup systems.

[GCE]

Morning

I see Nersa have published the latest update for NRS-097-2-1 Ed3 which amplifies the ECA stance on Neutral Earth Bonding

Extract pasted below and full document attached

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

[ACElectric]

It is quite clear now that most such inverters, as it is in the box, INCLUDING a Sunsynk - needing EXTERNAL (or internal) MODIFICATIONS, does NOT COMPLY WITH REGULATIONS and SPECIFICATIONS and as such are not allowed to be connected and/or installed in an electrical installation as required by the regulations.

If i have to "modify" a 20A cbi breaker to trip at 20A whether you do the modification inside the breaker or outside, -that breaker NO LONGER COMPLIES with regulation. Same with V-O-V gennies, you cannot change the the internal wiring to "make them compliant" They would have to be re-certified 1st.

It could then be quite possible, and easy, to successfully proof in a court of law that most coc's issued in such inverter installations, where such modifications are effected to modify the electrical apparatus, is in fact, invalid, because such modification would render the electrical apparatus classification/certification and approval invalid.

[GCE]

It is quite clear now that most such inverters, as it is in the box, INCLUDING a Sunsynk - needing EXTERNAL (or internal) MODIFICATIONS, does NOT COMPLY WITH REGULATIONS and SPECIFICATIONS and as such are not allowed to be connected and/or installed in an electrical installation as required by the regulations.

If i have to "modify" a 20A cbi breaker to trip at 20A whether you do the modification inside the breaker or outside, -that breaker NO LONGER COMPLIES with regulation. Same with V-O-V gennies, you cannot change the the internal wiring to "make them compliant" They would have to be re-certified 1st.

It could then be quite possible, and easy, to successfully proof in a court of law that most coc's issued in such inverter installations, where such modifications are effected to modify the electrical apparatus, is in fact, invalid, because such modification would render the electrical apparatus classification/certification and approval invalid.

I disagree with you - There is an option to select an output to activate a bonding "relay " if required. The same way that adding a Lan card or wifi module would be acceptable.

If I buy a 250Amp C/Breaker and need a Normal open contact , I buy the contact block and ,on some CB, have to open the CB to install the block or a shunt coil is a similar exercise - Do I need to send that back to certify ?

I buy a car and 3 months later decide that I want to fit a towbar , or mag wheels - Do I need to take it back for road worthy/recertification ?

With regards to a court of law and COC I would point you in the direction of SANS10142-1 Clause 5.1 - The method to create an earth neutral bond is clearly described as an option on the equipment and you would use a suitable sized relay/contactor suited for the installation and fault levels which comes with it's own certification.


5 Fundamental requirements
5.1 General
All commodities in an electrical installation shall be installed in accordance
with the requirements in this part of SANS 10142 and with the manufacturer's
instructions, where applicable.
NOTE 1 This clause contains the general safety principles applicable to electrical
installations.
NOTE 2 The manufacturer's instructions may contain more stringent requirements.

[ACElectric]

I disagree with you - There is an option to select an output to activate a bonding "relay " if required. The same way that adding a Lan card or wifi module would be acceptable.

If I buy a 250Amp C/Breaker and need a Normal open contact , I buy the contact block and ,on some CB, have to open the CB to install the block or a shunt coil is a similar exercise - Do I need to send that back to certify ?

I buy a car and 3 months later decide that I want to fit a towbar , or mag wheels - Do I need to take it back for road worthy/recertification ?

With regards to a court of law and COC I would point you in the direction of SANS10142-1 Clause 5.1 - The method to create an earth neutral bond is clearly described as an option on the equipment and you would use a suitable sized relay/contactor suited for the installation and fault levels which comes with it's own certification.


5 Fundamental requirements
5.1 General
All commodities in an electrical installation shall be installed in accordance
with the requirements in this part of SANS 10142 and with the manufacturer's
instructions, where applicable.
NOTE 1 This clause contains the general safety principles applicable to electrical
installations.
NOTE 2 The manufacturer's instructions may contain more stringent requirements.

Thank you, i will have to agree to disagree - this sudden burst of push-through regs (regarding this bonding issue) all of a sudden, and the dubious article published here (https://ecasa.co.za/technical/neutra...ing-clarified/) smells like an elastoplast plaster trying to fix the real issues, equipment not complying with SABS regs and standards.

It is actually a requirement that it should comply as a piece of equipment. - it does not. Part of the job of the inverter is to comply with the bonding regs - it does not.

Using your 250A CB argument, I then can sell a 250A breaker but, i 1st require you to install another device in series that makes sure it trips at 250A, my breaker simply does not meet the 250A standard. The car and towbar analogy i fail to understand as there are a complete different set of regs and the electrical regs does not apply.

It seems, as is the norm in this country, that double standards exist everywhere.

[Justloadit]

It is actually a requirement that it should comply as a piece of equipment. - it does not. Part of the job of the inverter is to comply with the bonding regs - it does not.

Can you provide the reference to this statement in the regs please.

[Dave A]

this sudden burst of push-through regs (regarding this bonding issue) all of a sudden, and the dubious article published here (https://ecasa.co.za/technical/neutra...ing-clarified/) smells like an elastoplast plaster trying to fix the real issues, equipment not complying with SABS regs and standards.

Oh boy. The regulators can't win.
Sometimes they're accused of not being responsive and dragging their feet on issues. Other times they're accused of rushing through patch job changes to plaster over the cracks.

Can't we just accept that it is a relatively new issue in SA that we didn't have with backup generators, but has become a significant issue with the small scale (dare I suggest what should actually be called "micro scale") embedded generation rooftop PV segment that has flourished in the past few years.

It is actually a requirement that it should comply as a piece of equipment. - it does not. Part of the job of the inverter is to comply with the bonding regs - it does not.

And there is a manufacturer specified solution that falls in the category "as intended in the original design."
It is widespread practice to have standard patch solutions to cover the different situations a piece of equipment might find itself deployed into.

Or should we just have banned the Sunsynk inverters until the manufacturer built their solution option into the box?

[ACElectric]

Or should we just have banned the Sunsynk inverters until the manufacturer built their solution option into the box?

(or approve ones that complies with N/E bonding for alternative supplies as per sans) - in order to force the manufactures of a $$$$$$$ expensive inverter, to comply and fit a decent built in relay WITH a failsafe and warning system should there be issues with N/E bond, unlike now if the contactor fails the bond is lost - no warning)

But, i rest my case. My point is NOT getting across, one of my weak points i guess. Sorry about that.



last try....From now on we should be able to buy "approved" cbi plugs without an earth terminal, circuitbreakers wihout ratings, connect V-o-V gennies as long as we modify the gennie, (and certify it ourselves) and cars without brakes or wipers until the manufacturer builds it into the box.

anyway have a good day i am off on my ktm 1290 r for the weekend.

[Justloadit]

(or approve ones that complies with N/E bonding for alternative supplies as per sans) - in order to force the manufactures of a $$$$$$$ expensive inverter, to comply and fit a decent built in relay WITH a failsafe and warning system should there be issues with N/E bond, unlike now if the contactor fails the bond is lost - no warning)

But, i rest my case. My point is NOT getting across, one of my weak points i guess. Sorry about that.



last try....From now on we should be able to buy "approved" cbi plugs without an earth terminal, circuitbreakers wihout ratings, connect V-o-V gennies as long as we modify the gennie, (and certify it ourselves) and cars without brakes or wipers until the manufacturer builds it into the box.

anyway have a good day i am off on my ktm 1290 r for the weekend.

Depending on the generator, it has an earth terminal connection, it does not have an internal earth bond as per your statement, as an alternative supply, it requires an earth neutral bond for proper operation, which is done at the time of installation, just as with an inverter. There is no fail safe mechanism on the generator either. Not connecting Neutral to earth, will not trigger the ELU when there is an earth fault, and the reason for doing this when the inverter is in islanding mode.

[ACElectric]

""" Can you provide the reference to this statement in the regs please.""""



page 260 AS PER MY POST

[ACElectric]

""""Depending on the generator, it has an earth terminal connection, it does not have an internal earth bond as per your statement, as an alternative supply, it requires an earth neutral bond for proper operation, which is done at the time of installation, just as with an inverter. There is no fail safe mechanism on the generator either. Not connecting Neutral to earth, will not trigger the ELU when there is an earth fault, and the reason for doing this when the inverter is in islanding mode.""""

excuse me --- what statement??????

and yes, some generators (quite a lot) does have a permanent N/E bond directly on the winding side, built into the gennie.

I have been repairing generators before the dead sea was even sick and i have seen a lot of gennies in my 60 years with a permanent N/E bond INSIDE the gennie.

anyway - i see no use debating this further following this somewhat biased narrative.

good day.