2 phase supply to a commmnercial installation and potential problems!

[timmy123]

I was called to an installation today following a PIR/ EICR done by a contractor. The contractor had advised the client to have a 3rd phase installed as the existing 2 phases are drawing around 95 amps each on full demand and the contractor has adviseed the client that this poses a danger due to fire risks/ overheating of the supply cables !. Each existing phase is protected by a 100amp 1361 type 2b cut out fuse. My understanding is that if all is as it should be then a demand of 95amps where there is a 100 amp fuse should not cause any problems. The client has been experiencing incandescant light flickering and ballast type flourescent light fittings periodically going off for a few minutes and then coming back on. The client has also commented that a historic electrical check indicated voltage fluctuations on the 2 phase DNO supplies to the building. The client is not planning to install any other electrical equipment. The DNO tails are 25mm csa.
My conundrum is whether a 3rd phase will solve his flickering problems or whether there is an inherent problem somewhere in the supply lines which will still exist even if a 3rd phase is introduced. The client is concerned about the cost of having to have a 3rd phase installed.
Does anyone have experience of a similar type of problem. Any comments on any aspect of what I have noted would be most welcome.

Many thanks

 

[needasparks]

Does this mean they have two separate 100amp supplies or a three phase meter.

I had a property that only had two phases to the whole area so could this be all that is available or is there an un-used phase present.

 

[mrelecbolton]

do a power quality survey

 

[Mushy Pea]

How do you know they are 100 amp? unless you have pulled fuses, cut outs are designed to use upto 100 amp, could be 80 amp or even 60 amp in there. Could also be 2 phase 3 wire if a polyphase meter present.