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EHU Issue Electrical Expert Needed

Discussion in 'TECH/MECH GENERAL' started by missbusybusy, Feb 8, 2013.

  1. missbusybusy

    missbusybusy Funster

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    Guys one for you Electrical experts

    Tried to work it out but got confused (easily done I know)

    We have had an issue when the trip on the EHU post kept tripping ,
    On the EHU posts this one had four out lets, each one had its own trip switch
    My question is are each of the single points fed by a single cable ?
    or
    do does the posts get get fed by one big cable and then this splits when it gets to the post for each socket ?

    Would this be the same for additional posts for the next pitches ?

    Thanks
     
  2. Wildman

    Wildman Funster

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    one large cable will supply all 4 trips/sockets each of which has a preset current limit. If the trip in your van is tripping then you may have a problem, if it is the trip on the post then you are almost certainly exceeding the permitted supply, i.e. drawing too many amps in total.
     
  3. missbusybusy

    missbusybusy Funster

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    So the cable has spurs from it ?
    Will the cable then go on to feed another post ?
     
  4. aba

    aba Funster

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    by rights it shouldn't but in theory it could feed another post but it all depends on what budget the installation had.
    in an ideal world each hook up post would have 3 blue sockets on and if point 1 failed under normal circumstances it wouldn't disable the other 2
    but costs for installing such a system are quite high.
     
  5. oldun

    oldun Funster

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    Your house will be on the same cable as all the houses locally but this should not have any effect on the integrity of your supply. Sockets on campsites will be wired up in in
    a similar manner. Each box should have its own overall "fuse" and each socket should also have its own "fuse".

    If the mains supply has sufficient capacity and the cables are adequate and well maintained then there should be no problem.

    However weather protection is not always good with campsite electrics and damp can often cause problems with electrics in the boxes and in your own extension lead.

    What you need to do is check each stage of the electrics, one by one.

    Check electrical devices for problems and wattage, internal fuses for capacity and integrity, mh ehu socket, extension lead (try another!) and then try another box somewhere else on the site to see if the problem still persists. If it appears to be a general site problem then only the owner can sort the matter out.

    Generally I find that the electrics on good quality EU sites is much better than it used to be and I find few problems. Even the dreaded reversed polarity is less general these days.
     
  6. pappajohn

    pappajohn Funster

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    if it is the smaller trip which trips then oo determine just what is tripping the post start by plugging in the hookup lead and unconnected from your van.
    no trip....lead probably ok.

    turn off the main breaker and all the other trips in your van.
    connect hookup lead.
    no trip...continue

    turn on the main breaker
    no trip...continue

    turn on each trip in turn until the post trips

    when it trips have a look at which circuits are on so you get an idea which circuit was overloading the post....charger, sockets, electric water heater etc

    if it,s the larger breaker which trips you probably have an earth fault which needs investigating.

     
  7. Sidney

    Sidney Funster

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    MCBs aren't perfect

    The incoming cable would feed something called a bus bar which is basically a strip of copper. All miniature circuit breakers (MCBs) in the power post would get their live supply from the same bus bar and then provide the "fuse protection" to each socket.

    MCBs are not perfect and one Type A MCB may perform different to another Type A MCB from the same production batch i.e one may trip more often then the other when presented with the same load.

    So... try another socket. If the problem follows you then you are either overloading the rating of the MCB or you having a wiring fault in your motorhome or hook up lead.

    NB overloading a MCB is easy when you're out on your travels... especially if you have brought a kettle or iron from home:Blush:

    6 amp @ 220v is 1320 watts
    10 amp @ 220 v is 2200 watts
    16 amp @ 220v is 3520 watts
     
    Last edited: Feb 8, 2013
  8. Sidney

    Sidney Funster

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    Of course when talking about power posts I should have said "normally" as I've seen some really worrying installations that could have only been carried out by complete numpties. Lastly when outside of the the UK all bets are off - regard each EHU with suspicion and wear rubber boots and gloves!
     
  9. eddievanbitz

    eddievanbitz Trader - Funster

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    We have three phase electricity into the site. The supply goes to a small building which houses meters and master switches and fuses. The it is distributed to three areas. Each area is on its own phase. Each phase is distribution box.

    Each distribution box supplies each post individually via underground armoured cable.

    Each post has a hidden RCD and then has a visible RCD of a lower value and four MCBs The visible ones are re-settable by the user. The hidden RCD and the switches on the distribution posts are not accessible by the public.

    This way we can shut down the site, and area or an individual post should there be a problem or if we don't like you? (Welsh people during England V Wales matches for example :Wink:)

    Eddie
     
  10. TheTwoOfUs

    TheTwoOfUs Funster

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    We were in Lloret when we had a thunderstorm which tripped the supply. Fetched the guy from reception who then proceeded to poke around in the box, in the pouring rain while stood in a puddle. Braver man than me:Doh:
     
    1 person likes this.
  11. missbusybusy

    missbusybusy Funster

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    ummm
    so if a site has a row of 12 RV,s with 3 EHU posts each with 4 sockets on would the furthest post have seperate 4 wires going to it ?

    and 4 seperate wires for each of the others and so on ?
     
  12. Sidney

    Sidney Funster

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    Well that all depends.

    More often than not the power post would have a single supply i.e. a 40 amp supply. But this would be dependant on the length of armoured cable, the number of cores, the cable size, the rating of each MCB, the number of sockets and some calculations undertaken by the electrician using the latest design guides. On site the cable may loop into one post and loop out to the next. There are many variables but unless you're designing an electrical circuit for your own campsite this should be of no concern to you.

    Anyone wanting an electrical design should employ an electrical design consultant.
     
  13. olley

    olley Funster

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    That's what the owner should have done on our site, instead of listening to the so called "leccy" 16x16amp EHU's all on a single 60amp supply.

    Ian
     
  14. missbusybusy

    missbusybusy Funster

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    thanks all, now I understand a bit more !! knowledge Is power they say ?
    problem was down to the cable, wire corroded inside of plug and intermittent connection if angled the wrong way

    cheers
     

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