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Three phase metering and neutrals

tattyinengland
I have been asked by the owner of a saw mill: Does a three phase meter (Old rotating wheel type) need to have a neutral connected to it in order to work correctly?


This is a property that only uses three phase motors for a saw mill and some lights (That I assume are single phase but quite how that works I'm not sure..........)


This is in a far flung country and is probably a TT system with no earths at all and certainly no RCDs. 


AJ - I managed to delete my last post when I was trying to attach a picture; I know you replied to me previous post, thank you very much, and I'm sorry to have deleted your reply to me. 


It seems that there are no neutrals what so ever into this saw mill......It looks to me like the terminals for the neutral are present but no neutral is connected. 


It may be that the lights are connected to earth as I know that there has been a lot of equi-potential type bonding going on - on this property between machines, structural steelwork, in the ground, all sorts. 


I cant get out there to see whats going on or advise at all because I cant see what effect my advise would have. Certainly if there is single phase lighting going on the neutral is essential. 


The metering I could possibly, with your help advise on. I'd love to post a picture but I'm not sure how. I'll copy this message now and try again........Dammed if I know how to attach a photo........
  • 0
    Zimbabwe, like most of Africa is 230V 50Hz world, with more like 400v  ish between phases, well more or less, often quite a bit less by the sound of things  in this case.


    Should we point out the meter terminal cover is missing.
  • 0
    HI Broadgage  


    as Mike says above - its 230V single phase and 400V three phase country. Same as here. I doubt they've got anything so complicated as lighting installed between phases, they've probably got a 400V/230V transformer somewhere, but I've no idea. 


    Thanks for your reply too....


    I'm fairly sure that there never were any covers for those exposed live parts - I doubt there is even a door for that meter cabinet - I know the Steel Wire Armour that supplies this lot is not terminated and the lives are just hanging from a pole transformer by their tunnel terminations. These are about 2m up a pole so the weight of the SWA is always hanging on those tunnel terminations...............Electrical safety in Zimbabwe is practiced by - don't touch it - and if it bites when you touch the lawn mower or saw motor - wear wellington boots and carry on. 

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