Neutral earth bond

[Tradie]

The nest question is at what point do you connect the neutral earth bond, at the load terminals, after the inverter output double pole breaker, or just any random point that is most convenient?

How would you identify if someone has installed a permanent neutral earth bond.

Its all these "silly" questions that nobody wants to ask that are creating the challenges we face on a daily basis.

What happens is one person start a narrative, and every one just follows blindly, because they dont want to ask the silly questions or dont know any better.

I am surprised nobody has started telling people you have to install a DC fireman's switch on the side of the building for the panels, if not trust me it is coming. It might no be a bad idea.

Due to the theft risk becoming a reality, apparently an electric fence energiser could be a new way to prevent theft. You can connect it to the rails because the energiser does require 3 earth spikes and the panels are double insulated, it could prevent panel theft and it is also DC

[Justloadit]

Mmmmmm the pulsing of the electric fence will charge the glass and would transfer this charge to the electrical system via the DC cables. Hence the reason for earthing the frames, to prevent static buildup, and to reduce any influence of a lightning strike close by.

[Tradie]

So it would prevent theft of the panels

Mmmmmm the pulsing of the electric fence will charge the glass and would transfer this charge to the electrical system via the DC cables. Hence the reason for earthing the frames, to prevent static buildup, and to reduce any influence of a lightning strike close by.

[Derlyn]

@Justloadit. Yep. How many times have I heard guys refer to the panel earthing as "lightning protection" and just smile. Earthing and lightning protection, of course, being 2 totally different beasts.

Interesting story of where earthing didn't work..... Many decades ago whilst working on the Saldanha Sishen project, the electrical department received reports of shunters shocking whilst busy with shunting duties on coaches in the harbour. Investigations started. It was found that this phenomina only happened occasionally, so it was quite difficult to pin point. After many months it was found that this only happened on coaches laden with lead concentrate and only when the train encountered rain en route from sishen. The combination of lead concentrate, steel of the coach and rain(electrolyte) was creating a huge battery.

The only solution was to remove the electrolyte as the coaches were already earthed through the rails. It was decided that all lead concentrate coaches be covered with a tarpaulin, preventing rain from entering the coaches.

Problem solved.

Strange story, but true.

[Tradie]

The bonding, surge and lightning protection confusion is real, add a few experts in the field and before you know it, people are installing 16 mm wires with earth spikes all over the place, including to the inverter and nobody can understand why the inverter and electronic is the first to pop, with the response, but we installed 16 mm wire from the panels to the DC control which is linked to the AC control and linked directly to the inverter which is also bonded to the batteries and the earth spike dotted around the building ... mmm

I am sure we can all agree with the term used frequently in earthing arrangements... The path of least resistance ...

I am not aware of any device that can suppress a lightning strike, I have sat in many lightning protection course and seminars and seen how the industry has evolved from separate earth terminals on dedicated socket outlets and UPS systems, installing 2 separate earth wires in trunking, to sperate ground spikes and mats. How the earthing evolved for cellphone towers and earthing arrangements for borehole pumps, we installed in remote areas, every time they were blown to bits no matter what type of protection we attempted to install.

[Derlyn]

The secret is to get lightning to strike on something other than that which you are wanting to protect.

[Tradie]

The picture on this site sums it up.

https://www.earthcor.co.za/products/lightning.html

[Tradie]

When you install solar panels on the roof, you need to ask a simple question, are you looking to protect the system from lightning, or reduce the static everyone refers to.

If it is lightning, you certainly dont want to be connecting 16 mmsq plus earth wires directly to the frame or rails of your panels, linked directly to your equipment (Path of least resistance).

Instead you will be installing crows feet which are higher than the panels, 70 mm wires along the highest point (above the panels) then down to an earth bar, which will be connected to earth spikes mats as required.

If you looking for surge or static protection, then a 6 mm wire down to an earth bar, which will be the point where the earth spike is connected.

To sum up a very basic domestic 60 amp single phase installation and an 8 kw inverter:

A 16 mmsq earth wire from the meter to the main DB, a 10 or 16 mm from the main DB to the AC control.

A 6 mmsq wire from the solar panels down to the common earth bar close to the earth spike for the solar installation.

A 6 mmsq wire wire from the equipment to the common earth bar for bonding all the equipment.

A 6mm sq wire from the common equipment earth bar down to the common spike and panel earth bar.

Why would I use this method, because if you dont have lightning protection and rails or panels are hit, you want the spike to go down the wire (path of least resistance) to the common spike earth bar and dissipate into the ground, if any excess power does get back up into the common equipment earth bar, there are surge protection devoices , which might be able to handle it, or it will be blown to bits, like most of the surge protection devices we see after a hit.

I have installed 10s of thousands of rands worth of surge protection, for customers, I can't tell you of one instance, that if the building took a direct hit the equipment survived. One advantage to installing the equipment, insurance companies do favour claims where the customer has taken precaution.

My house was hit a couple for months back, it sounds like the crack of a whip and everything goes dark, a couple of weeks later the assessor arrived, checked the setup and authorised the full claim. we replaced everything, Alarm, XVR's, all the TV's and all the blown electronic components.

[Derlyn]

Exactly

[Justloadit]

The termination Tradie refers to is a "Star" connection. The central point is the earth bar.
If you connect earth wire to a piece of equipment, then feed earth wire to another piece of equipment, and so on, it is referred to as a "Daisy" chain connection. If the lightning srtikes the first piece of equipment where the earth connection starts, then off course the energy will travel down the wire and take out everything in its path to dissipate into the earth bar.

[Thys LOW Elektries]

7.16.4 Deals a bit with "Neutral Earthing" 7.16.4.3 is very interesting though, have never seen one of thee stickers? :confused
https://www.theforumsa.co.za/forums/...nverters/page5 also an interesting read
The two wire supply cable was an old English standard, not sure when South Africa went over to three core supply cables though.
The old part of Orania only have two core supply cables coming into the meterbox outside the house.
It is surprising to see how frequently the new electricians remove the neutral earth bridge and then don't understand why the readings
are funny and the earthleakage don't work.

We also had rather shocking experiences when the neutral made a bad connection on the overhead lines and everything earthed become "ALIVE!"

[Tradie]

This is why it is VERY VERY IMPORTANT when reading the information shared on social platforms, to understand the type of power supply and the earthing arrangement, otherwise you going to be butting heads with others who may not have the same arrangement.

I am going to say it again and again, dont take everything you read on social media as facts, they might be correct, but not for your application.

This is why we have SANS regulations, with "guidelines" to steer us in the right direction to create a reasonably safe elctrical installation.

You have to be very careful when offering advice on public forums or groups.

For example our grid supply is a 5 wire system, L1, L2, L3, N, E (star point centre tap) using a TN-S earthing arrangement, which taps off to the houses, some have 5 wires meter connections 400 VAC and other have 3 wire meter connections (230 VAC), TN-S. We dont install earth spikes and never have for as long as I have been an electrician (over 40 years).

7.16.4 Deals a bit with "Neutral Earthing" 7.16.4.3 is very interesting though, have never seen one of thee stickers? :confused
https://www.theforumsa.co.za/forums/...nverters/page5 also an interesting read
The two wire supply cable was an old English standard, not sure when South Africa went over to three core supply cables though.
The old part of Orania only have two core supply cables coming into the meterbox outside the house.
It is surprising to see how frequently the new electricians remove the neutral earth bridge and then don't understand why the readings
are funny and the earthleakage don't work.

We also had rather shocking experiences when the neutral made a bad connection on the overhead lines and everything earthed become "ALIVE!"

[Derlyn]

We also had rather shocking experiences when the neutral made a bad connection on the overhead lines and everything earthed become "ALIVE!"

That's where an earth spike is a handy thing to have.
If the neutral is lost, you'll feel that tingling on the taps. Common fault in our area, close to the sea where the connections on the poles corrode regularly.