Lightning protection vs surge protection

[ians]

Lightning protection vs surge protection.

Fact - Depending on your insurance company You are not covered for surge protection unless you specify it.

Fact -If you have existing lightning protection on the building with inspection points etc ...you need to verify that your DB boards inside the building have the correct class of lightning protection.

Fact - lightning protection is generally automatically covered by insurance companies...which will check the weather to verify that there was actually a storm on the day of the claim.

You have got more chance of being robbed at gun point in Durban than your property being hit by lightning...however electrical surges caused by the unstable power supplied by Durban electricity department ...theft of neutral bars and cabling ...is becoming as common as house invasions.

A customer has requested we install "lightning protection" to cover equipment inside the factory... I have learnt a few things today which i didnt even know were an issue...consult a specialist and make sure you are aware of the type of protection required by the insurance company... there are various means to protect the equipment... makes sure that you have done your homework and understand the consequences of installing incorrect protection.

[ELECT 1]

Well this is an interesting subject.
In Cape Town according to some suppliers the single surge arrester is the most popular.
There is a single and neutral one as well.
We install the single ones on single phase installations, and three of them on a 3 phase installation on the load side of the main circuit breaker.
What happens on one of our installations, during load shedding, some of the locals went to cut the neutral and earth
wires from a sub station nearby,/ So instead of 220v coming through there was a surge of much more, (i dont know how much) but the
275v arrestor tripped and sent the surge to earth and caused the main switch to trip.

Big problem now, the maid was ironing and thought the iron tripped the power. So, she switched on the tripped main switch and the rest is
history, Tv, decoder, washing machine and various other stuff damaged.
So whats the point of having a device to protect you when it can sort of be over ridden.

Next question, Is protecting the neutral necessary as the excessive voltage will make its way to earth anyway.
They make one for the neutral, so i assume there would be a need.
Any suggestions

[ians]

Well this is an interesting subject.
In Cape Town according to some suppliers the single surge arrester is the most popular.
There is a single and neutral one as well.
We install the single ones on single phase installations, and three of them on a 3 phase installation on the load side of the main circuit breaker.
What happens on one of our installations, during load shedding, some of the locals went to cut the neutral and earth
wires from a sub station nearby,/ So instead of 220v coming through there was a surge of much more, (i dont know how much) but the
275v arrestor tripped and sent the surge to earth and caused the main switch to trip.

Big problem now, the maid was ironing and thought the iron tripped the power. So, she switched on the tripped main switch and the rest is
history, Tv, decoder, washing machine and various other stuff damaged.
So whats the point of having a device to protect you when it can sort of be over ridden.

Next question, Is protecting the neutral necessary as the excessive voltage will make its way to earth anyway.
They make one for the neutral, so i assume there would be a need.
Any suggestions

I use to suggest people install a clearline trip connect in the meter ...however i am having so many issues with this product ...still waiting for them to sort out the unit which was returned to them a couple weeks ago...i theory it works but after our last massive bang on a site ...i am starting to question both lightning and surge protection.

It is more for peace of mind for insurance purposes ...than a functional solution.

2 things you need to be aware of with regards to lightning and surge protection...make sure the surge protection box is ticked and make sure if you are installing in a building like many schools for example which have external lightning protection ...that you install class 1 and class 2 lightning protection...you will not be covered if only class 2 lightning arresters are installed ... rather stay away from buildings which have this type of external protection it attracts lightning.



3 phase applications

Class 1 lightning protection goes for around R13000.00

Class 2 lightning protection costs around R3000

[ELECT 1]

IAN"S thank you for you input, but here in Cape Town we arent into the lightning thing as the Transvallers are.
We have lots of cable theft, and especially when load shedding is on.
Most of the time we are hit with a surge at these times.

I have talked to many electricians, all give different views on how the surge installation should be done.
I am now talking in a pure domestic installation.

[Justloadit]

Well this is an interesting subject.

We install the single ones on single phase installations, and three of them on a 3 phase installation on the load side of the main circuit breaker.
What happens on one of our installations, during load shedding, some of the locals went to cut the neutral and earth
wires from a sub station nearby,/ So instead of 220v coming through there was a surge of much more, (i dont know how much) but the
275v arrestor tripped and sent the surge to earth and caused the main switch to trip.

Big problem now, the maid was ironing and thought the iron tripped the power. So, she switched on the tripped main switch and the rest is
history, Tv, decoder, washing machine and various other stuff damaged.
So whats the point of having a device to protect you when it can sort of be over ridden.

Next question, Is protecting the neutral necessary as the excessive voltage will make its way to earth anyway.
They make one for the neutral, so i assume there would be a need.
Any suggestions

What happened here is that the surge arrester did its job, and self destructed by tripping the circuit breaker by becoming a short circuit .The misunderstanding of surge protectors, is that they work indefinitely, this is not the case, (what actually happens, is that the material of the surge arrester melts with the energy from the surge causing a short circuit, absorbing the energy as the protection of the surge). They are designed to absorb the excessive energy from the surge. Well when you concentrate that amount of energy into a device which is 25 to 30mm diameter and 5 to 6mm thick, you can not expect the device to survive. It will self destruct, which during the process cause the circuit breaker to trip and protect the load. With in this device there are special fuses, which when the disc is destroyed/Short Circuited, the internal fuses blow. This is so designed so that a fire is not created by the destroyed surge material.
One way round this is to have high current fuses in series with the surge arrester, which causes the circuit breaker to trip, and the fuses blow. Then have a voltage monitoring device, which is on the surge side of the fuse, controlling a contactor supplying the load. This will prevent the user from reconnecting the load, and would require an electrician to clear the problem.

The resaon that there is a Neutral to Earth surge arrester is precisely for the times when the Neutral is disconnected from the supply. The 3 phase loads on the supply could cause huge voltage variations between Neutral and the supply Lives.

[ians]

Pretty much what we have been doing since around 2008...the only issue is in areas were the voltage is so unstable that it drops below 180 or increases above 260 ...which is pretty much what becoming the norm ...add in load shedding and you got yourself a real problem...you wouldnt need a flasher unit for your lights

[GCE]

Hi Ians
I noticed that the earth and neutral are swapped around on the surge arrestor - I see that the earth is in the "PE"terminal - cant make out anything on the bottom terminal

To me this means that any surge that is being clamped will be put to the neutral and that the neutral will be spiking.
Came across it before and it was the cause of intermittent ELU tripping

[ELECT 1]

What happened here is that the surge arrester did its job, and self destructed by tripping the circuit breaker by becoming a short circuit .The misunderstanding of surge protectors, is that they work indefinitely, this is not the case, (what actually happens, is that the material of the surge arrester melts with the energy from the surge causing a short circuit, absorbing the energy as the protection of the surge). They are designed to absorb the excessive energy from the surge. Well when you concentrate that amount of energy into a device which is 25 to 30mm diameter and 5 to 6mm thick, you can not expect the device to survive. It will self destruct, which during the process cause the circuit breaker to trip and protect the load. With in this device there are special fuses, which when the disc is destroyed/Short Circuited, the internal fuses blow. This is so designed so that a fire is not created by the destroyed surge material.
One way round this is to have high current fuses in series with the surge arrester, which causes the circuit breaker to trip, and the fuses blow. Then have a voltage monitoring device, which is on the surge side of the fuse, controlling a contactor supplying the load. This will prevent the user from reconnecting the load, and would require an electrician to clear the problem.

The resaon that there is a Neutral to Earth surge arrester is precisely for the times when the Neutral is disconnected from the supply. The 3 phase loads on the supply could cause huge voltage variations between Neutral and the supply Lives.

Hi Ians
I noticed that the earth and neutral are swapped around on the surge arrestor - I see that the earth is in the "PE"terminal - cant make out anything on the bottom terminal

To me this means that any surge that is being clamped will be put to the neutral and that the neutral will be spiking.
Came across it before and it was the cause of intermittent ELU tripping

I cant really read the instruction, but normally on the ones that we install the earth would be at the bottom and the neutral at the top...
i suppose a different manufacturer will have a different setup

[ians]

Hi Ians
I noticed that the earth and neutral are swapped around on the surge arrestor - I see that the earth is in the "PE"terminal - cant make out anything on the bottom terminal

To me this means that any surge that is being clamped will be put to the neutral and that the neutral will be spiking.
Came across it before and it was the cause of intermittent ELU tripping

We wire them as per the supplier specs ...it depends on the type and manufacturer :

https://surgeprotection.co.za/products/12-00418-db-boards-3-phase

http://www.surgetek.co.za/diagrams.php