Connecting to mains electric.

Discussion in 'The Beginner' started by Hollyberry, Jan 24, 2012.

  1. Hollyberry

    Hollyberry Funster

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    Morning everyone,
    V confused trying to connect to mains electric.

    Poster inside the wardrobe door advises me to "Switch off main switch" before connecting. I can find no main switch.

    Book that came with m/home doesn't mention a main switch but tells me to connect the electric cable and "connect the switches 4 & 5"--these switches in the diagram are circuit breakers 220v & 240V.

    At the moment it's parked in the sun and solar panel reading is giving it charged to 50% so I don't have to connect to the mains--but I feel I should know how to.

    M. home is Bennimar Aereo if that's of any help.

    Many thanks for any advice.
     
  2. hilldweller

    hilldweller Funster Life Member

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    We never do though I can see a bit of logic. Say you had a mains heater plugged in with a towel over it. Plug in outside, get chatting and FIRE.
     
  3. DESCO

    DESCO Read Only Funster

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    Must agree have read but don't bother. In my opinion more important to plug into van first before hook up point.
     
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  4. Dodgey

    Dodgey Funster

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    We're, I suspect complicated, by having an RV but if the internal RCD is on when we hook up more often than not it trips the EHU bollard.
     
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  5. Hollyberry

    Hollyberry Funster

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    So I don't need to find this illusive "main switch"?


    I just plug one end of fully uncoiled lead (I read the warnings!!!!!) into m/home and one end into my house? And that's it?
     
  6. scotjimland

    scotjimland Funster Life Member

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    in a nutshell... yes..

    if you want, you can read this article from the Caravan Club... a bit long winded but it may be useful ..

    http://www.caravanclub.co.uk/media/1026258/hookinguptothemains.pdf
     
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  7. Pikey Pete

    Pikey Pete Read Only Funster

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    There should be a mains trip switch somewhere in the van. It is usually a grey box, with black trip switches and is often found somewhere near the inside part of the EHU socket.
    It could also be within the area where the heating boiler is located.

    The instructions usually do say switch off before connection to the mains, but I don't think many people do.

    Pete:Cool:
     
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  8. hilldweller

    hilldweller Funster Life Member

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    Go for it.

    Somewhere you should see something like a smaller version of your house "fuse box". You really do need to know where this is in case it ever trips. Ours is in the back of the wardrobe and shoes could hit the trip button and we'd have no power, so I made a cover to stop this.

    When you find it, look for a button marked TEST. When all is running OK press TEST to make sure the safety circuit works. Afterwards you will have to press a reset almost next to it.

    See below for what you are looking for.....

    http://www.leisureshopdirect.com/ca...umer_Units_and_Circuit_Breakers_for_230v.aspx
     
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  9. scotjimland

    scotjimland Funster Life Member

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    common problem when you are connecting a 230v/120v transformer.. the inrush current exceeds the MCB trip point ... whether it trips or not depends on

    * MCB Rating in Amps

    and

    * MCB type.

    Type B - trips between 3 and 5 time full load current

    Type C - trips between 5 and 10 times full load current

    Type D - trips between 10 and 20 times full load current

    The most common type found is Type B.

    * and probably the least understood or thought about..

    the exact point on the sine wave cycle when you plug in .. with luck it is passing through zero volts .. bad luck it is on the peak .. this can explain why on the same MCB it sometimes trips and sometimes doesn't

    Whether you have your on board switch on or off will make no real difference.. it's just luck .. or bad luck when it trips..

    You can install a soft start transformer and there are also anti surge devices to reduce the surge..
    Frankly I never bothered, I took my chances with the sine wave cycle .. and the good nature of the site warden .. :Laughing:

    Note:

    If you switch off all 110v appliances ie fridge , water heater, etc. BEFORE plugging in this will reduce the surge considerably and may explain why you find it better to switch off the main switch before connecting the EHU

    THIS INFO is ONLY relevant to US RVs WITH 230v - 120v transformers..
     
    Last edited: Jan 24, 2012
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  10. Dodgey

    Dodgey Funster

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    MCB stuff interesting, the rest I have the jist of.

    Yes, turning all loads of, even the fridge and connecting, with internal off, reduces, but doesn't eliminate the trip, mind you it is rare apart from the house trip, it must be the lowest rated as it takes anything up to three attempts to get connected:Doh:
     
  11. scotjimland

    scotjimland Funster Life Member

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    I tried to keep it simple ..:Laughing:

    your domestic breaker may be needing replaced or if it's supplying the ring main sockets in the house it may already be loaded when you connect your RV EHU ..

    If that's the case and it's an issue, better if you had a dedicated circuit and MCB feeding a single outlet for your EHU ..
     
  12. slobadoberbob

    slobadoberbob Read Only Funster

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    we just plug in

    We just plug in the cable.. however we do have a Sterling pure wave inverter / charger fitted. That is switched off until we have connected the power lead.. then we switch on the inverter.

    However the fridge will change (if on) from LPG to 230v as soon as the power lead is connected as will the flashing lights on the microwave if it is left plugged in (both are of course on the 110v) circuit.

    Bob
     
  13. carry on then

    carry on then Read Only Funster

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    I would say its the RCD thats trips out when you connect a live mains hook up to the van , not the MCB.
    The reasoning is that RCD is the earth leakage device ( residual current device) and MCB is Miniature circuit breaker. Its the RCD that has the 'test' button on it, not the MCB's. When you hit the 'Test' button, you are actrally creating a direct short in the circuit, which the RCD should notice and act upon by tripping the switch out.

    The RCD will see the electrical connection as a short when connecting to the mains, especially if a device is already switched on as well ( a 220v light bulb or kettle ect ect. RCDs usually work at 30milliamp, so it will pick up ( trip)on anything that appears live to it

    The MCB will only 'trip' if the load imposed on it by devices that are switched on is to much for the circuit, and if that's the case your possibly overloading the wiring and circuit anyway. DONT just change an MCB without having the wiring checked out as well . Its easy to change a 10A MCB to a 20A one, but your wiring may only be rated for 10A.

    Occasionally the MCB will go as well, normally only if it was a faulty device that caused the short to start with , like when a light bulb in your house blows.
    If you connect the EHU to your house whilst something 'mains powered' is switched on , you may trip the House RCD or the MH RCD , whichever one is the more sensitive will go first.
    it IS common for the spring in the RCD to go weak , as its in the 'stretched' position whilst the power works (most of its like). The spring is only in its relaxed state ( not stretched) when the RCD's switch is in the off position
     
  14. scotjimland

    scotjimland Funster Life Member

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    nice theory .. but wrong ..

    RCDs (used to be called ELUs- Earth Leakage Units) do not pick up on load or shorts .. that's the function of the MCB which trips when the current is more than it's rating.

    An RCD protects by constantly monitoring the current flowing in the live and neutral wires. Under normal circumstances, the current flowing in the two wires is equal. When an earth leakage occurs due to a fault in the circuit or an accident with the equipment, an imbalance occurs and this is detected by the RCD, which automatically cuts off the power .

    Pressing the test button simulates this imbalance

    It's normally the EHU post MCB that trips due to high inrush to the 3kw transformer.. not the RCD in the van,. .. I've seen this happen many times..
     
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  15. pappajohn

    pappajohn Funster Life Member

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    How very true Jim......

    At Misterton last year.......plugged into post, no power to RV
    check post MCB and main RCD, MCB tripped.
    switch back on, still no power.
    Breaker in RV tripped, switch back on.
    STILL NO BLOODY POWER !!!!!! :Angry:
    recheck post, MCB tripped again, turn back on.....power to RV :thumb:

    just unfortunate timing. :Sad:
     
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  16. carry on then

    carry on then Read Only Funster

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    So your saying i got my wires crossed :Rofl1: . told you there was a short there somewhere didnt I ?:Doh:
     
  17. Dodgey

    Dodgey Funster

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    Yup, but it rairly get used now and frankly selling soon, house not RV:BigGrin:
     
  18. scotjimland

    scotjimland Funster Life Member

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    going fulltime ? :Laughing:
     
  19. Dodgey

    Dodgey Funster

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    :BigGrin:
     
  20. scotjimland

    scotjimland Funster Life Member

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    good luck ..:Smile:
     
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