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volt drop

  • 24-05-2013 6:33pm
    #1
    Registered Users, Registered Users 2 Posts: 193 ✭✭


    I have a quick volt drop question. I have 6 outside lights which are 5 meters apart with 100 watt Edison screw bulbs, the problem is the supply from the switch to the first light is 100 meters. I used a swa for the cable. I think 2.5 square is ok but just need a second opinion.


Comments

  • Registered Users, Registered Users 2 Posts: 378 ✭✭frankmul


    600w will take 2.6 amp
    mV/A/m value for 2.5mm is 18
    You could get up to 190 meters before the voltdrop gets near 9 volts.
    You must remember that you need to calculate from the DB and take the size of the cable feeding the switch into account.


  • Registered Users, Registered Users 2 Posts: 193 ✭✭irishkopite 2011


    Cheers frankmul. It's actually 93 meters from the switch to the light and roughly a 7 meter run from the board to the switch, just thought it would be easier to explain it by saying a 100 meter run.


  • Registered Users, Registered Users 2 Posts: 566 ✭✭✭adrian92


    2.5 sq mm Cu is more than sufficient. 1.5 sq mm would be ok unless in a rural location with a weak electrical utility infrastructure.


  • Closed Accounts Posts: 699 ✭✭✭mikehammer67


    adrian92 wrote: »
    2.5 sq mm Cu is more than sufficient. 1.5 sq mm would be ok unless in a rural location with a weak electrical utility infrastructure.

    DSO(network) VD can be a factor but it's not part of the calculation


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