thanks for the explanation and agree with you on the cost of SPDs vs potential damage. Btw 3 phase it’s 450-500 for SPD. Yes I also have adaptor surge protectors. Was thinking to have two lines of Defence for sensativr appliances and the whole house SPD for fridge, ovens, lights, all other devices etc.

The other thing I’m quite confused about is the “kA” rating. Is a 40kA whole house SPD ok?

After reading some info, diy .. etc..
I bought some MOV Varistors (14D471) and soldered them inside my another replacement extension plugs.
Replaced with 5A fuse in the main plug.

Hopefully it will 'work' if got strike.. 😅
Mov have lifetime.. the more it received surge/spike, even in normal use, it will shortens its life..

oh  good idea.  :thumbsup:
  I want to try 

can you comment/ check  this data  if  suitable for as like your application  . TQ

https://shopee.com.my/Varistor-Metal-Oxide-...087.10322710509

Should be ok.
Overal its all generic mov.
Saw its from sabah, u in sabah?

Im using this one.
https://shopee.com.my/product/135112285/104...53-1641267822.9

Also bought the generic cheaper blue one.

I am from  Subang J.  KV. 

i select that 1 cos  the advert  has spec details  that i feel are good.  The other  with no specs normally  i skip.

Type: Metal Oxide Varistor (MOV)
Manufacturer: Nippon Chemi-con
Part Number: TNR12V471K
Element Diameter : 12MM
Max. Allowable Voltage: AC 300Vrms / DC 385V
Max. Peak Current: 4,200A @20µs
Max. Energy: 60J @2ms
Rated Wattage: 0.4W
Max Clamping Voltage: 775V @ 25A
Capacitance Typical : 345pF @1kHz
Varistor Voltage V1mA: 470V (423 ~ 517)V , ±10%

now after search again  i  saw this ,  and have  chat the seller  who is  manufacturer  as the  datasheet link show many .
https://shopee.com.my/1pcs-Varistor-05D471K...1804.6578019841

yes 40 kA  is  fine.    mean it can handle  peak 40kA  current  in a surge condition / microseconds.
the clamp voltage is important . lower the better .

look for the ones  with  a  status window.  if it goes dead  the window will turn red. so need to change or replace the module.  my guess is  about 10 years life  unless you get a really big surge.

ive been reading up and trying to find out whats the difference between installing a type 2 SPD upstream vs downstream of the RCD/RCCB. Could anyone explain this to me? I understand that typically SPDs are suppose to be installed between the main CB and RCD/RCCB. Is it considered wrong to install it downstream of an RCD/RCCB? what happens when its install downstream, does it provide the necessary protection?
havent been able to find alot of info on this.

ive been reading up and trying to find out whats the difference between installing a type 2 SPD upstream vs downstream of the RCD/RCCB. Could anyone explain this to me? I understand that typically SPDs are suppose to be installed between the main CB and RCD/RCCB. Is it considered wrong to install it downstream of an RCD/RCCB? what happens when its install downstream, does it provide the necessary protection?
havent been able to find alot of info on this.

The RCD may be damaged if RCD upstream of SPD.

for this, SPD will still function as usual and provide protection to all plugs and appliances etc right? understand that RCD could be damanged so long as everything after RCD is safe.

Based on ST literature

Therefore, the following is recommended:
1. In general, to install SPDs upstream of RCDs (RCDs installed
upstream of SPDs may operate on the expected surge currents);
2. If SPDs are installed downstream of RCDs, the expected surge
currents to earth should not exceed the immunity value of the RCD.

Based on Hager literature

Should RCD’s be required in the installation as additional
protection or to ensure the requirements of fault protection
are satisfied, then the SPD will need to be installed upstream
of the RCD. Where this cannot be avoided, the RCD should
be of the time-delayed or S-type.

I think it is best to follow the experts rather than experimenting because usual RCD type AC is instant trip, we don't use S type or time delayed in residential

It adds on in the main DB box. Refer 3:11 for the general diagram https://youtu.be/oa_a4HTVqoQ?t=191

Depending on what supply (1 phase or 3 phase), you need some room in the DB box (of either 2 modules width, or 4 modules width).
To create room, this may require moving around some MCB's; or if the DB box is full, a new bigger box preferably with similar layout need to be installed.

Similar layout meaning if currently u are using a 12x2 row (24 slot)
----------
----------

expand to something like a 16x2 row (or 16x3 row).
-------------
-------------

If you expand to a 27x 1 row format
------------------------------

yes,  it give u 3 more slots space as 27>24
but the problem is I dont think your existing wiring lengths can stretchhhhh that much (mostly it is just nice only, no slack).
Hence if its 12x2 row in the beginning then u need to get something that follows along the same format as the old box.

The SPD still need a bit of kung fu to do properly although its install location is confined to within the DB box.
Technically the connection is the easy part but that's assuming the customer DB box has sufficient space else need to upgrade bigger box and/or remove unused MCB to fit and move out existing MCB as the "wong wai" is closest possible to the main MCB [50cm max = shortest bestest].

https://library.e.abb.com/public/76853add5a...olutions_EN.pdf
pages 19, 21, 22, 23, 30 (see TNS/TT system diagram, Malaysia use TT).
Back-up protection dedicated to the SPD = At bare minimum, SPD must be behind at least the main MCB (for indirect strike/T2).

It is recommended to have another MCB dedicated just for the SPD alone (whilst the main MCB will take care of shorts, but additional one MCB still not expensive to implement) in case the SPD totally failed due to damage (and created a short circuit) after kena too many strikes.

Thanks for the info.

My DB doesn't have enough space to install another 4P SDP. If I pull all the 4 wires (3L + N) from (after the main MCB but before the RCCB) out of the main DB, into another small db box so I can install a new MCB (dedicated for SDP)+ the 4P RCCB, does the 50cm rule apply from where I pull the 4 cables out, or from the 2nd MCB?

Saw these on Shopee; will this work? The length of those cables (3L + N + E) definitely exceeds 50cm already, unless you measure from that 2nd MCB on the right

Thanks for the info.

My DB doesn't have enough space to install another 4P SDP. If I pull all the 4 wires (3L + N) from (after the main MCB but before the RCCB) out of the main DB, into another small db box so I can install a new MCB (dedicated for SDP)+ the 4P RCCB, does the 50cm rule apply from where I pull the 4 cables out, or from the 2nd MCB?

Saw these on Shopee; will this work? The length of those cables (3L + N + E) definitely exceeds 50cm already, unless you measure from that 2nd MCB on the right

Well FWIW, think I better place my trust in SPD mfgs who have a test lab to simulate lightning arcs..than someone selling on shopee.
Its kind of a rule for proper SPD installation, else they wouldn't bother to state the total length <50cm all over.
refer https://www.beama.org.uk/asset/1FE338CE-496...37F3DEA6C683C6/ page 53 onwards

How about replacing the DB box with a bigger one? Let's see what's the current configuration (share pic) first.