Surge protection

[Isetech]

This is a topic I have avoided for some time. On occasion I have had customer ask why I dont fit surge protection into the new DB's we install, my response "you dont have to install surge protection where we live".

What I have learnt from insurance claims in the past, no matter how much money you spend on "surge protection" , if the insurance company checks the weather for the day of the claim, if no lightning happened on that day, sorry for you. So you need to check your policy to make sure you have a clause in your policy which covers you for other types of high voltages surges, which could be caused by transient switching current, stolen neutral conductors, faults on the mains supply caused by transformer short circuit etc. In other words everything not lightning related.

I have had 2 requests this week to install surge protection, 1 for a factory with a 1000 amp supply required by the insurance company and the other a home owner who requested a DB replacement.

SANS 10142-1 2021 ED3.01 covers it in



Annex I
(normative where surge protection
is required or installed (see 6.7.6))
Installation of surge protective devices (SPDs) into low-voltage
systems in order to protect the installation
NOTE The installation of surge protection is not compulsory, but where it is installed or deemed
necessary by the risk assessment (or both), compliance with this annex is required.
I.1 Installation of surge protective devices (SPDs) into lowvoltage
systems
I.1.1 Surge protection
I.1.1.1 Surge protective devices (SPDs) are used to protect, under specified conditions,
electrical systems, components and equipment against various transient overvoltages
and surge currents such as lightning and switching surges. The selection, connection
and application of SPDs installed in low-voltage installations shall be in accordance with
this annex. The type and class of SPD to be incorporated in the lightning protection
design will depend on the risk assessment and protection level. The Risk assessment
needs to be carried out in accordance with SANS 62305-2 and tables Q1.1 and Q1.2 in
annex Q.
I.1.1.2 Class I surge protective devices (SPD), that comply with the requirements of
SANS 61643-11, are installed to protect an installation against partial lightning currents.
(Iimp 10/350μs) and induced overvoltages, caused by atmospheric discharges (lightning).
NOTE In order to protect against transient and switching overvoltages, , class II SPD should be
installed in conjunction with class I SPD and energy coordination between the SPDs, as per
SANS 61643-12, needs to be proved.
I.1.1.3 Class II surge protective devices (SPD), that comply with the requirements of
SANS 61643-11, are installed to protect an installation against transient overvoltages
and surge currents (In 8/20μs) caused by switching operations or induced atmospheric
discharges.
I.1.1.4 Class III surge protective devices (SPD), that comply with the requirements of
SANS 61643-11, are installed to protect an installation against switching surges and by
limiting transient overvoltages (Uoc 1.2/50μs; 8/20μs) caused by switching operations.
NOTE It is recommended that a class III SPD be used in conjunction with an energy coordinated
class II SPD.

[Isetech]

What do I have to consider for the factory: Before I start planning the installation. First step is to find out if there is any form of lightning protection on or around the building, if there is already some form of protection, Class 1 protection will be required at the mains.

What is the difference between class 1 and class 11 protection, a lot of money.

Once you have decided on the type and make of unit, its best to contact the supplier and discuss the requirements for their equipment. There was an engineer who was very clued up on surge protection, I hear he retried and is now contracting to the company.

I would then select the type of overload protection circuit breaker or fuse, and wire size required between the mains, fuse and surge protection and lastly the earth wire.

I have request that the insurance company supply a breakdown of the surge protection required, that's where the fight started, do they want class 1, class II and class III protection or is the surge protection only required at the main DB? I am still waiting for a response, maybe someone who has done surge protection for insurance companies or had a claim rejected because of certain criteria was not met, can share the info.

[Isetech]

Here is one tricky parts, they refer to SANS 61643-11, as we have all recently learnt, nothing you buy anymore is SANS approved, so which IEC standard or other standard would comply?


I.1.6 Protection against overcurrent and consequences of an SPD
failure
I.1.6.1 Protection against SPD short-circuits shall be provided by overcurrent protective
devices that are selected according to the SPD manufacturer’s instructions, tested to
comply with SANS 61643-11.
I.1.6.2 The cross-sectional area of the conductors that connect the overcurrent
protective devices to the line conductors shall be rated according to the maximum
possible short-circuit current withstand (see manufactures specification).
I.1.6.3 The short-circuit withstand of the SPDs (in case of SPD failure) together with the
specified associated (internal or external) overcurrent protective device shall be equal
to or higher than the maximum short-circuit current expected at the point of installation,
taking into account the maximum overcurrent protective devices specified by the SPD
manufacturer. In addition, when a follow current interrupting rating is declared by the
manufacturer, it shall be equal to or higher than the expected short-circuit current at the
point of installation.
NOTE As a general rule where the PSCC is more than 10 kA, it is advised to consult a specialist
on the selection of overcurrent protective device in figure I.3. and I.4.

[Dylboy]

I dig into this subject at times and listen to podcasts and read a bunch and i still have questions such as yours.

I want to go to DHEN south Africa and book an hour with that chap that does articles in that ECASA magazine and try get this ironed out.

I enjoy the topic quite a lot.

Time is a factor sadly to getting it done and learning but I will get there.

Interesting on the insurance people stating need surge protection but won't say what type.

Sent from my CPH2197 using Tapatalk

[BobZA]

What do I have to consider for the factory: Before I start planning the installation. First step is to find out if there is any form of lightning protection on or around the building, if there is already some form of protection, Class 1 protection will be required at the mains.

What is the difference between class 1 and class 11 protection, a lot of money.

Once you have decided on the type and make of unit, its best to contact the supplier and discuss the requirements for their equipment. There was an engineer who was very clued up on surge protection, I hear he retried and is now contracting to the company.

I would then select the type of overload protection circuit breaker or fuse, and wire size required between the mains, fuse and surge protection and lastly the earth wire.

I have request that the insurance company supply a breakdown of the surge protection required, that's where the fight started, do they want class 1, class II and class III protection or is the surge protection only required at the main DB? I am still waiting for a response, maybe someone who has done surge protection for insurance companies or had a claim rejected because of certain criteria was not met, can share the info.

I am no expert but you are on the right track. Class 1 is required if there is some form of lightning protection on the building. And as you say Class 1 is more money and often takes up more space. And typically if you install Class 1 you want to install this in conjunction with a Class 2 unit. Dehn has an excellent compact unit that has both Class 1 and 2 that would probably be a great for the factory installation.

The factory installation is more complicated. At 1000A the fault level of the board will be higher, probably around 20kA. Also in factory installation there may be sub-db's and consideration should be given to if surge protection devices are required on them - usually if they are not in the same building, on in some cases if they are far away. Here typically Class 2 are used. Given the high fault level it would be wise to consult a supplier - the likes of Dehn or Surgetek. It will take the "guess work" away. They would advise the correct device, backup protection, wire sizes etc.

To be fair the insurance company cannot really specify what they want as really a risk assessment / inspection would be required. I guess they really should at least have some kind of minimum guidelines. Surge protection is not exact science in that a lot of assumptions have to be made about the likely lightning strike that may occur in that particular area. And of course there is no guarantee. A direct strike will probably still do a lot of damage no matter what. I would assume that if you install at minimum a Class 2 surge protection device in the DB and follow the manufacturer's instructions then that should satisfy the insurance company.

[Isetech]

To be fair the insurance company cannot really specify what they want as really a risk assessment / inspection would be required. I guess they really should at least have some kind of minimum guidelines. Surge protection is not exact science in that a lot of assumptions have to be made about the likely lightning strike that may occur in that particular area. And of course there is no guarantee. A direct strike will probably still do a lot of damage no matter what. I would assume that if you install at minimum a Class 2 surge protection device in the DB and follow the manufacturer's instructions then that should satisfy the insurance company.

As someone mentioned a while back, the insurance company is not in the business of designing and installing surge protection or electrical installations for that matter, however they need to reduce the risks, the way to reduce risk, put the risk back into the customers side of the fence and add clauses which reduce the risk on their part. It is up to your broker to make sure you understand the policy, if you choose not to read and highlight part of the policy you dont understand or not happy with, or couldn't be bothered to read the policy, its not the brokers fault.

As the customer it is your responsibility to read your policy, make sure your house has a COC, make sure the people working on your site are suitably qualified for the work they are doing.

What is important is you understand why they have requested the "surge protection" and makes sure you understand the difference between surge protection and lightning protection.

All you have to do is look back at the event over the past 6 months, a claim for damage to equipment on your property would result in a request for surge protection.

Most important, make sure you are covered for all surge events, not just lightning.