IEC Test Recommendation Varistar and HV/LV Distribution Fuses

Yes, YouR electrician can.

33Kv can kill you instantly if you have no clue. You have no clue.

HIRE AN ELECTRICIAN OR ENGINEER.

Proper quality control testing is not simple or cheap and it is VERY unlikely the surge arresters are faulty, more likely they are dying due to over voltage events (voltage surges, lightning, etc) or due to incorrect surge arrestor selection.

Get someone qualified in to check the site, otherwise the problem is likely to continue to occur.

"The things here's is that..we have plenty of pieces in our show cases (store) and specification never been a compromised.Still my question is how to test these staff's when we put them into system most of them resulted to failure after sometimes.Could anybody suggest me how to Test them??

-----------------------------------------

" best thing one can do when it's raining is to let it rain".

Henry Wadsworth Longfellow (American poet 1807-1882)

As Jack of all Trades said, it is unlikely that your arresters are failing because they are faulty, especially if the last a while before failing. If you don't know how to test them, you certainly do not have the skills and knowledge to test them. It is not a task for the untrained and unequipped. Better to hire a qualified testing company to do that for you.

But as was also said, the likely cause is overvoltages or surges that are beyond the capability of the arrestors to withstand. They are doing their job, to protect the rest of your system! You need to do more investigation of the electrical supply to see where and why it is out of tolerances.