Metal Halide Fitting trips MCB - once a fortnight!

Discussion in 'Electricians' Talk' started by Deano070578, Feb 5, 2010.

  1. Deano070578

    Deano070578 Member

    I have a metal halide 400w outside fitting - which trips every fortnight or so. It is turned on with a seperate photocell. It doesn't appear to have any relation to weather.

    Could the fitting itself have a high earth leakage? what is the way forward on this?
  2. Removed 4

    Removed 4 New Member

    - which trips every fortnight or so. ......

    Dean: Metal halide fittings are particularly prone to tripping during the tropical zodiac or sideral zodiac of Aquarius - somtimes extending to the Pisces period.

    The best way to overcome this, is by using an insulation tester.......

  3. Oakey dokey

    Oakey dokey New Member

    I`m not so sure lucia is right,i think it has something to do with PMT-my mrs trips almost constantly for 2 weeks mind you tho she isn`t made of metal halide...
  4. Removed 4

    Removed 4 New Member

    I`m not so sure lucia is right......

    That makes three of us, dear.....

    Lucia x
  5. mr sillys

    mr sillys New Member

    I agree with ferm grip since using the lunar calendar to plant my veg and flowers I have had great results

    the use of the insulation tester is a good idea for electrical work but did not help my kale


    i hope this helps

  6. Deano070578

    Deano070578 Member

    So you are optimistic that over the next 6 weeks this problem will hopefully pass?

    Thanks for your help Lucia.
  7. Removed 4

    Removed 4 New Member

    Oh, that's right Deano! Pile on the guilt 'til I eventually agree that your light fitting has an earth leakage problem every two weeks.......

    You men are all the same!

  8. mr sillys

    mr sillys New Member

    you may need to plant some thing for spring this may help your metal halide


  9. Accaman

    Accaman New Member

    Hey Ho Horatio!!!! Pffft!
  10. Deano070578

    Deano070578 Member

    Back to seriousness now guys....

    What are the signs I need to look for to try and find this fault? This fitting has been up a month and has only tripped twice.
  11. JP.

    JP. Screwfix Select

    Is there a timer fitted somewhere which turns on a device once every fortnight?..the device could be leaking and compounding total leakage to the point where it knocks out the RCD once every two the sum total.
  12. Deano070578

    Deano070578 Member

    The fortnight thing is just approximate...

    And it trips the MCB on the circuit that a 400w metal halide and a 70w metal halide is connected only....
  13. JP.

    JP. Screwfix Select

    Oh right apologies Deano, thought it was an RCD knocking out.

    Hmmmm..on the assumption that a 6 Amp breaker is fitted is it possible that the combined inrush of the two MH units<u></u> is taking out the B Type? However not being au-fait with the inrush properties of Metal Halide luminaries, I must say that this is only a guess.
  14. Deano070578

    Deano070578 Member

    I've asked a electrician friend of mine and he has said exactly the same thing.

    The cable is 1.5mm - and it is a 6A Type B MCB.

    What is the best way forward here? Thanks again for your time guys
  15. pcelectrics

    pcelectrics New Member

    Back to seriousness now guys....
    If you're looking for a serious answer, then try a serious forum instead of this juvenile chat room. Try this one:

    I've asked a electrician friend of mine and he has said exactly the same thing.
    Yet this "electrician" wasn't able to recommend a remedy?
  16. Deano070578

    Deano070578 Member

    he has suggested using a Type C MCB 6A - as he thinks the circuit overloads for a short period when both the 400w and the 70w kicks in.

    If the cable is 1.5mm, could it cope with a Type B 10A MCB as an alternative?
  17. Removed 4

    Removed 4 New Member

    Dean, it has nothing to do with the current rating of the MCB - and certainly nothing to do with "overloads for a short period". But, it has everything to do with the tripping characteristics of the MCB 'type'.

    A Type 'C' device would be far more tolerant of the nasty 'spikes' caused during the start-up period for such a high inductance load.

    I've no doubt that a replacement 10A 'B' would improve matters slightly, but if you're going to the trouble of changing the MCB, you might as well fit a 'C' type.

  18. JP.

    JP. Screwfix Select

    Concur Lucia..a C Type is indicated. However Deano before using this I think it would be pertinent to check the EFLI value first.

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