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Ct single phase metering

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  • 24-11-2014 9:35pm
    #1
    grousedogtom
    Registered Users Posts: 463 ✭✭


    Hi
    I'm upgrading a 12 kva single phase supply to 29 kva supply at the moment. I'll be running a 3 X 35sq swa between the new Esb meter cabinet and back to my consumer unit. My question is what type of main switch would be best suited to terminate the 35 Sq into. Would it be best to install an enclouse type switch fuse beside the existing consumer unit and connect from there with panel flex as 35 Sq swa will be quite bulky. Any suggestions appreciated.


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    #2
    Par1
    Registered Users Posts: 263 ✭✭Par1


    Have you done a calculation to see if 35sq is sufficient for what you need. Thats considered a big load for single phase 29kva draw

    ESB will advise what switchgear you need on pre connection consultation @ design stage.. sw fuse - busbar chamber will be what you will be using. 35sq is not difficult to work with.

    You cant make connection with flexables unfortunately at that point as integrity of termination would not be accepted by ESB. Your Sub main will have to be fused up and down stream also.


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    #3
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    Par1 wrote: »
    Have you done a calculation to see if 35sq is sufficient for what you need. Thats considered a big load for single phase 29kva draw

    I was just about to say that 29kVA would not be an issue for a 35sq. Unless it is a long run. Then I noticed that it is a single phase load. On that basis I would have to agree that the cable size should be checked carefully because it sounds small. Would it be difficult or impractical to use a 3 phase supply?


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    #4
    grousedogtom
    Registered Users Posts: 463 ✭✭grousedogtom


    No 3 phase available unfortunately, rural property, 35 Sq is the cable size specified by Esb network and will be fused accordingly.


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    #5
    Par1
    Registered Users Posts: 263 ✭✭Par1


    grousedogtom wrote: »
    No 3 phase available unfortunately, rural property, 35 Sq is the cable size specified by Esb network and will be fused accordingly.

    ESB will only advise and would never spec a SWA cable. I would not take there word on sizing, id do my own calculation just to be safe as you will be responsible for any implications.

    Why are they not using concentric cable if they are sizing cable? I take it theres a mains and switch room. do you know the size of the incomer cable or fuse rating?


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    #6
    grousedogtom
    Registered Users Posts: 463 ✭✭grousedogtom


    No switch room, this is just a dairy farm, my total load at peak periods will be no more that 100 amps for a short period. The Esb will be carrying out all connections in the Meter cabinet ct chamber so that's why they specified 35 sq. A far as I know this is the largest connection from Esb on single phase, a couple of years ago they specified 50 sq for the same connection but now 35 sq.


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    #7
    Par1
    Registered Users Posts: 263 ✭✭Par1


    grousedogtom wrote: »
    No switch room, this is just a dairy farm, my total load at peak periods will be no more that 100 amps for a short period. The Esb will be carrying out all connections in the Meter cabinet ct chamber so that's why they specified 35 sq. A far as I know this is the largest connection from Esb on single phase, a couple of years ago they specified 50 sq for the same connection but now 35 sq.

    Pity you couldnt get the 3 phase supply as it would be more beneficial for machinery availability altough im not to up to date on milking machines etc but generally most motors run better on 3 phase.

    3 phase is a little more expensive but worth it in my opinion for various reasons i.e load balance and accessory/machine selection/availability.

    Double check the SWA with ESB that they will make connection as im sure they will not terminate or even work with SWA. It would be a shame to buy cable then not be able to use it.


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    #8
    grousedogtom
    Registered Users Posts: 463 ✭✭grousedogtom


    Thanks for the advice, yes definitely swa as I done a similar job about a year ago and it was swa Esb connected at the ct chamber, in an ideal world all modern milking parlours would be 3 phase considering the amount of motors involved but more often than not the only choice is single phase.


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