Electric trip fault

[BazandPam]

Hi
We have a Bailey Pageant Bretagne series 5 and have just returned from Kingsbury Water Park,Whilst there the Electric in our van kept tripping out. I tried all the appliances with a seperate lead and RCD but none tripped the RCD. The power would stay on all day without any problems but as soon as the Truma heater was used on either gas or electric it tripped within an hour.Can anybody help with the problem.

 

[Damian]

If you are referring to the space heater then on gas it will have no effect on mains power consumtion as its ignition is by its own Duracell battery igniter and the flame is held on by the thermocouple.

As for tripping the RCD, without knowing what else mains powered you had on at the same time, is difficult to point to any particular reason.

 

[BazandPam]

Thanks for replying
i am wondering if there is some kind of cut out within the space heater that trips the MCB in the consumer unit as the trip says sockets, fire and fridge. We have run fridge and all appliances on a seperate RCD to test them and they have not tripped.
We have noticed the ducting for the blow heater runs quite close in front of the consumer unit and wondered if the heat could cause it, or also could condensation be a factor as this is the first time we have been away in the caravan at this time of year. I have also been told that re-setting the MCB so many times could have made it weak, but again it only seems to trip when the heating is on.

 

[ProfJohnL]

Hello Baz and Pam,
The MCB's and the RCD work in very different ways to provide protection.

At a basic level the RCD should only trip if there is current leakage to earth fault. and the MCB should only trip when more current (AMPS) are drawn than should be.

As you have been unable to identify the offending appliance, I strongly suggest you should get a qualified electrician to investigate.

 

[xtrailman]

The easy way forward is to replace the CB, cb's don't like repeated trips, it weakens the device.

However if the new CB trips, don't reset it, you have a fault and need to find it!

I would also test the RCD before doing anything else, via the test button.

 

[Dustydog]

Our previous Pageant series 5 Vendee had a similar problem. It turned out to be a defective battery charger unit. Bailey had been supplied with a faulty batch. It is possible you have one of these?
However unless you are a competent electrician I'd get an expert to sort it for you. A faulty earthing system in a caravan could prove lethal.

 

[WMRussell]

You say that it appears to trip even with the heater running on gas, when it is running on gas are you using the blower to circulate the hot air, if so it could well be a afault with the blawer itself.

 

[ProfJohnL]

Hi WM
I think it highly unlikely to be the fan that is causing the problem,as the fan runs on 12V not mains.

 

[DerektheSecond]

What charges the battery? also the op dosnt state if they have a battery fitted if they dont then the 12v would run straight off the mains ,the problem initially points to Dustydogs reply

 

[ProfJohnL]

Hello Derek,

The RCD problem might be the battery charger, but it would only be something affecting the mains side of the charger not the 12V side.

RCD's don’t work by looking for a current flow in the earth circuit, but by comparing the current flowing in both the live and Neutral of the incoming mains supply. provided there is less than 30mA difference, it continues to allow the current to flow. If the imbalance exceeds 30mA the RCD operates and disconnects (in the case of the caravan) both the live and neutral incoming supply

In fact it does not matter how much current flows in the earth or Continuous Protective Conductor, that by its self will not cause the RCD to trip.

The 12V DC system must use both a +12V and 0V wires and must not rely on the chassis (which is electrically earthed) to complete the 12V circuit. However most 12V appliances do connect the 0V line to their casing, and this may make electrical contact with the caravan chassis.

So whilst the 0V line of the 12V system may make contact with the caravan chassis, it is not intended as part of the 12V circuit. However it is therefore possible for some 12V circuit current to appear on the chassis, but it should be entirely contained within the caravan and not appear on the earth conductor in the EHU cable.

Even if some 12V current did find its way onto the Mains supply cable earth, as the RCD does not monitor the earth current it would not cause it to trip.

 

[Dustydog]

Prof John said:-
In fact it does not matter how much current flows in the earth or Continuous Protective Conductor, that by its self will not cause the RCD to trip."

I've just taken my Bailey for its annual servcie which gave me a chance to look at the Owners Handbook.
I quote verbatim:-

" The mains unit replaces the conventional fusebox. Similar but larger units are often fitted in newer houses.
The unit gives overload and earth leakage protection for the 230v electrical supply in your caravan".

If I believe Bailey then either an earth leakage or overload will cause the trip??

I'm no spark and I really think Baz should consult a qualified expert who knows about these fittings in caravans.
Better safe than sorry.

.

 

[Damian]

Quote for illustration only "
Hello Derek,

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The RCD problem might be the battery charger, but it would only be something affecting the mains side of the charger not the 12V side.

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RCD's don’t work by looking for a current flow in the earth circuit, but by comparing the current flowing in both the live and Neutral of the incoming mains supply. provided there is less than 30mA difference, it continues to allow the current to flow. If the imbalance exceeds 30mA the RCD operates and disconnects (in the case of the caravan) both the live and neutral incoming supply

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In fact it does not matter how much current flows in the earth or Continuous Protective Conductor, that by its self will not cause the RCD to trip.

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John, I dont know what you are using to write your replies on but as you can see they are VERY hard to read with all the unwanted
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[xtrailman]

I am an electrician.

The RCD will trip if the earth is in contact with the neutral, a RCD monitors the current in both live and neutral conductors, if the earth is connected to the neutral the RCD will trip, but no CB will.

A earth to neutral fault can be very difficult to trace.

 

[BazandPam]

Thanks Guys
Im going to replace the MCB anyway. as one reply asked if a battery is on the van, yes we have a battery fitted. I did try the test button on the consumer unit, once pressed it tripped and i reset it without any problems. I have a friend who is a spark but not trained on caravans he should be able to sort it,but as with all sparks he is always busy. any more help would be appreciated.
Cheers Baz

 

[Guest]

I don't know about the gas fire causing it, but I do know the 175degC limit thermostat on the electric heating will, infact it often causes this fault.
Get your sparks to check either of the two black wires in the control box behind the fire for a connection to earth, if a connection is found then you have found the fault. Also check between blue and green of the 125degC stat for the same reason, albeit unlikely
Problem now is access to the stats, this requires the fire to be removed as their behind the gas flue pipe connection.

 

[ProfJohnL]

Fao Damian,
I either use the forums word processor. or Microsoft word to prepare more complex answers. I don't get any of the extra characters showing in either the preparation of the document, or in the final posting, so your reveal is the first hint of there being a problem.

What I do note is that when preparing a reply, is that sometimes when I need to edit a sentence or correct a spelling, sometimes after the edit point the remiander of the line flips to the next line leaving a gap at the end of the line.

I also note that when pasting from Microsoft Word, invariably the last paragraph changes its font!

Any suggestions welcomed.

 

[ProfJohnL]

Hello Dusty,

My description and the Bailey handbook are in complete agreement.

In a caravan, any fault that allows mains current (30mA or greater) to leak to earth will cause the RCD to trip. There is a leakage to earth, but its not the current running through the earth that causes the RCD to operate, it is the fact that the current comes from either the live or neutral and causes the incoming supply to be unbalanced. The RCD detects the unbalanced supply and operates.

Whatever the cause though, I do agree that Baz should get the system checked by a competent sparky.

 

[DerektheSecond]

John are you saving "word" in html that would cause the problem

 

[Dustydog]

Thanks John
I think I now understand that earth leakage can only be caused by curerent drop in the + or - hence the trip. Maybe the owners handbooks could be more informative. However for a stupid old dog like me ,a little knowledge may be dangerous.

I've noticed your posts over the last 4 - 6 weeks contain all the corrupted text. Have you changed something?
What setting are you using ; "disable or enable rich text"
Are you using Explorer 7 or 8?

Surely our boffin John Duncan can answer the problem

 

[Guest]

John, I wonder if using Word, your writing in HTML? I sometimes compose or often copy and paste from Word without problem, but I write in normal text and let the website sort out the encoding?
Seems to me theres a conflict in the formatting which this forum is unable to understand, so displays what is always there, but should be unseen?

 

[xtrailman]

Thanks John
I think I now understand that earth leakage can only be caused by curerent drop in the + or - hence the trip. Maybe the owners handbooks could be more informative. However for a stupid old dog like me ,a little knowledge may be dangerous.

I've noticed your posts over the last 4 - 6 weeks contain all the corrupted text. Have you changed something?
What setting are you using ; "disable or enable rich text"
Are you using Explorer 7 or 8?

Surely our boffin John Duncan can answer the problem

Being picky but +/- are DC supply terms, not AC, which uses live and nuetral, the way a RCD works is quite simple, it contains two coils one passing the incoming current, the other the out going, when the current is different, the inbalance causes a trip.

If the nuetral is in contact with earth AFTER the RCD, this then allows some current straight to earth, some back on the return neutral, the current depending on the circuit impedance.