spectrum48k

Small factory containing several CNC machines (415/3/50) and I suspect there's an "issue" with the ground floor 240v electrical sockets...

Ground floor has one PC computer
Upper floor has one PC computer

Today the ground floor computer wouldn't switch on.

Took it off site and it works fine, time and time again. Took it back to site and it won't work. In fact it won't work on any of the ground floor sockets, BUT works fine upstairs.

Asked local electrician to test the ground floor sockets and he says they're fine - kicking out a constant 240v, when he stuck his voltmeter in the socket.

Other ground floor sockets have smaller equipment plugged in (router, modem) and they work fine.

Any ideas what it could be ?

c_maguire

Could be that there is a lot of noise on the phase for the downstairs sockets which won't be picked up by a DMM (need an oscilloscope) and is a problem for the PC. If you have a UPS you could try using that with the PC downstairs as a test (it should clean up the supply somewhat if that is the problem).
Kevin

cossie-nutter

iTrader: (45)

What about the upstairs pc trying down stairs ??

jaytc2003

iTrader: (1)

modem router etc only work on a small ampage and voltage so they should work if the current is there. The pc I imaging is trying to draw more ampage than is availble. What about turning of the cnc machines as a test and then trying the pc ?

scoobynewbie72

iTrader: (1)

Wont make any difference as its not tripping due to overload, the power supply isnt happy with the supply so wont switch on from what i can see,

If you hadnt had a sparky look id say u had lost the neutral to the sockets, but without a proper look I wouldnt say 100%,
It must have a Live there or he would have known on his meter, if a earth is missing it normally shows this too, but its not unheard of for lost neutrals to cause confusion with cheaper testers,(On TNCS earthing Installations)
all guess work from op`s info.

spectrum48k

yep, tried it - same problem. PC won't switch on.

spectrum48k

it's a head scratcher!

spectrum48k

I'll ask the sparky to try this.