2013/01/06 at 5:57 am #10831farangParticipant
i am working on a project in Asia.
The project has a 800 kva oil filled transformer. 33K primary, 220/380 output.
distribution was done by a single 3 phase 4 conductor cable (NYY) from a Breaker in a panel near the transformer to a distribution box where 3-4 homes were than connected thru a 3 phase breaker and meter to each individual house/villa.
Basically 3-4 homes/villas on main one cable.( 1 bus bar feeds 3-4 houses, connected loads) in the local panel.
My problem is all the homes/villas have 3 phase panels but all loads are single phase and multiple single phase panels are installed in several locations throughout the properties.
All of the conductors are the same size 4 X 25sq mm that feed the property from the local distribution/meter panel.
the problem is faults, leaks, overloads, unbalanced phases effect all houses that are connected to the same local distribution panel so a problem at one house is felt by the others on that cable.
My fix would be to run new wiring from each house back to it’s own breaker/meter at the main distribution panel next to the transformer. The furthest House/Villa is 270 meters from the Main MDB and transformer.
I also would like to know how this effects my neutral as all loads are single phase.
I have asked questions on the forum before, i need advice and suggestions. Things don’t get installed correctly here, I did not design the installation or have any part in the installation and connections.
I just need to try make it more efficient and reliable.
And no there are no drawings, plans, cable locations for the site, each house was connected by the contractor using various cable sizes and breakers. No two are the same as each was done by a different “electrical guy”
Bad splices and overheated wires abound, they will be sorted as we progress.
So any help or suggestions including C-4 will be appreciated.
Here “experts” abound, but no one wants to tell them what they will do to fix the problem or how much it will cost, none can back their plan, fix with DATA and a plausible explanation of what they will do.
Thanks2013/01/06 at 11:29 am #12721chi plusParticipant
hi in my own humble opinion in other to restore the system back in a good working condition i think that first of all u have to re acess the loads carry out a load shedule then distribute your loads accordinly then do your load calculations to determine the actual cable size for each load then proceed to identify the under sized load cables remove and replace them with the normal guage and dont forget to distribute ur loads properly in the db
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