I do not know, do I need rewire this shop or not and explain WHY?

Question

I need write a clear recommendation, not a report, to the owner. Certain information is:
The cables are all PVC/PVC imperial size.
The protective devices are all BS3036 semi - enclosed fuses,
Many existing cables are surface - mounted and within touching distance of the people using the shop,
There are a number of long trailing extension leads,
The supply is three - phase, four - wire and the earthing system is TN-S.
Beside:
1. There is a freezer in this shop with existing 7/044 twin cable, which is considered to be too small. A design has been carried out and the new cable will be a 10/4mm squares twin+c.p.c cable. The cable is to be installed within the fabric of the building, but all current system must remain in place.
2. The local distributor is upgrading its system to a TN-C-S system increasing the prospective fault to 9kA. I want to investigate the appropriate type/s of protective device that might be used giving reasons for my choice/s.

Answer 1

i do not know your location but if you are uk,new laws make it against the law to do electrical work unless qualified to do so.if you are qualified then you shouldnt need to ask these questions.in ANY case if ever any doubt contact a qualified and competent electrical contractor

Answer 2

listen to the gaffer!!! you clearly dont know what your doing, get an approved electrician to inspect the wiring, if you dont my friend you could go to jail!! the hse are looking for examples to hall you up before the beak!!