I tried Googling for "European testing laboratories" and the like, but got too many irrelevant hits, and no obvious suggestions. You might ask the local electrical inspection authority for a list of acceptable labs (testing agencies), or ask an electrical contractor what listings they must comply with, or even look inside a few electrical panels and see which testing agencies have been involved. (In the U.S., it might be UL, ETL, CSA, and some others; in Europe or Oman, I don't know.)

I have an email acquaintance who lives in Oman. He doesn't work in this field, but maybe he will have an idea. If so, I'll introduce the two of you. Good luck!

If testing as per IEC (60439?), KEMA (Netherlands), ASTA (UK) or CESI (Italy) are the ones i know. Expensive when seen from an Indian perspective. However, CPRI India labs have been approved by ASTA so you can get the tests done at a fraction of the cost in Europe.

You can check out the facilities by visiting their website http://www.cpri.in/

Hope this helps.