Why do desktop power supplies and GPU's keep blowing?

[The Ghost]

I'm not an electrician but I some clever heads together - http://www.electriciansforums.co.uk/threads/im-not-an-electrician-but-i-some-clever-heads-together.117521/
Some of you may remember the above thread where the guy had umpteen blown power supplies and GPU go into melt down. I have now been asked by a tenant as to why they seem to have the same problem. All I have is an MFT and am at a loss as to how to point the tenant toward an answer.
I feel in some way that I should know as I do the maintenance etc. across the building. Of course the answers to this may well be beyond my tech. abilities however as the problem above, it just would be nice to solve. I do not think @beachlover ever did get any definitive answer did he. Or maybe there is not an answer, but I find that hard to accept..... any wunderkind out there?

 

[Wilko]

Hi V, like all good mysteries one should start by establishing exactly what has happened (rather than what one has been told). Gather all evidence, take pics etc. Perhaps try to recreate the events, with clamp meters in hand and NCIS nearby . Once wiring given a clean bill of health perhaps look at the equipment. Over the years I have had issues with some switch mode psu just not liking to be power cycled. Run forever if left on, lasts 3 mth if powered off and on 3 times a day (saving polar bears). That other thread hurt my head

 

[Uheat – Jake]

Built a few PC's and it Sounds like a short, when taking the PC apart inside did you take any static protection? Or is there a spacer under the mobo? Or the mobo has just shorted over time

 

[The Ghost]

Hi Wilko, yes its good to be reminded to take it step by step and logically for a starters. So far I just tested the voltage (240v) and did Zs being 0.39 L-N 0.49 L-PE. However on my MFT on the L-PE the warning came up that indicated "Noise" on the circuit. So there are extraneous voltages on E. This building is one of three in the complex in question. It is a single storey row of 17 Units of around 10m² each (roughly) about 20 years of age) All supplied from the switch room MCCBs' which is a sub main of the main intake in building two, which is a two storey. All SWA of varying sizes 3 phase. Into Merlin Gerin switch gear in the units. Quite straightforward rings/radial for comms/lights (flourescent) Buildings are Steel girders and sort of corrugated steel roofs.

The single storey had a fault, outside each unit is an emergency lighting bulkhead, due to seeing them flashing etc investigated and found a neutral connected to the earth at one point. It had been like that for twenty years showing no problems. Obviously rectified tested etc. So far it is only one unit that has complained of this problem. If there are other faults like this may explain a lot?

 

[darksideby182]

I pretty sure the PSU would clean up the 12v and 5v rails supplying the Mobo and GPU could well be geting issues using cheap PSU's and the GPU pulling alot of current off the PSU.
Would be nice to know the spec on the components that have been used.