Apologies in advance if this has been brought up earlier but I'm not trolling through god knows how many previous posts
I thought I'd mention a 3 phase fault I had recently for the benefit of a lot of guys on here who are learning or are not familiar with working on 3 phase systems.
See if you can work out the fault. ( if you know it please give the guys a chance to try and work it out first.......ta).
The factory where I work has its own 500kva transformer.
Built in the early 60's this supplied both the factory and the remote office block.
I recently had the DNO run a 3 phase/N SWA cable into the office block so I now have 2 separate supplies.
I then installed a 3 phase board and ran several single phase sub mains to various c/units around the office block.
From the main board I then ran a 3 phase 'dedicated supply' to the server room for the IT dept ( this is the only 3 phase board in the building apart from the incomer).
I was called to the IT dept because the main server had 'crashed'. UPS had kicked in but lots of things not working.
Main thing I noticed on my way there was ALL the power and lighting in the offices was still on.
Anyway...........work this out if you can
Testing the 3 phase D/B in the server room gave me these results.
L1-N = 230v.
L2-N =230v.
L3-N =230v.
L1-E = 230v.
L2-E = 230v.
L3-E = 230v.
N-E = 0v.
L1-L2 = 432v.
L1-L3 = 432v.
L2-L3 = 0v.
What fault could cause this, bearing in mind, ALL power and lighting was still on !
I'll wait and see if there's much interest before giving any clues if their needed but I'm sure many have come across this problem on here just thought it would be good to share with others that haven't.