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Caravan Tripping House Electrics


gingerbreadman
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Hello fellow members, I'm experiencing problems with the connection between the house and the caravan. Every time that I attach the main ehu cable to the external socket ( it's the same used by caravan sites and this was fitted by qualified electrician ) the house electrics trip and will not reset until I unhook the caravan. I've been using this external socket for about 8 months with no problems and the caravan always charges up nicely, yet now I have this problem. I'm thinking about possible moisture issues at either end of the cables or that the caravan charger may have developed a fault. One sounds like an easy fix whilst the other doesn't. Not knowing about electrics, I thought I'd ask here if anyone could give me any idea's I could try before calling out an electrician. Probably something stupid, the caravan is in for it's service on the 12th of January and if I need to could possibly let them know in advance of any issues. Thanks in advance to everyone who helps with my problem, best regards, Gingerbreadman ( Paul ) :mellow:

PAUL, 2005 Mitsubishi Shogun Warrior 2. 5TD, Towing A 2005 Bailey Pageant Provence .

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Has it ever tripped when on site? Test the EHU lead for continuity/shorts by using a multimeter. if thats O. K. it may be time to bring in an electrician as I don't think you should go any further without expert knowledge. ....Peter

Peter and Sandy pulling a 2016 Coachman VIP 565 with

2016 Ford Kuga 2. 0. 180 ps. Titanium Nav.

Retired and loving it.

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Hi

 

had the same problem, house RCD sensitive to moisture, changed hook up lead, easy test, hey presto sorted so now waterproofed the connection.

 

Ali

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If the caravan is being serviced by an Approved Workshop on the 12 Jan all of your electrical system will be checked including your hook up lead. In the meantime (unless you know what you are doing or want to pay someone who does) remove the plug & isolate the socket.

For any additional information or advice please have a look on my website. .....

www. thecaravanmedic-swindon. co. uk

 

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To establish where the fault possibly lies you need to narrow down the possibilities. .. Turn off the RCD in the caravan and then connect to the house. Does it still trip? - If it does the issue is likely with the EHU cable. The likely hood is that it is not the connection on your wall because it does not trip when the cable is not attached.

If you attach just the cable without a caravan on does it still trip? - If so you have a fault with the cable.

 

If you cannot test this with another cable then likely you will need an electrician I'm afraid.

 

Alimac. .. House RCD's are not sensitive to moisture, they are sensitive to current leakage. .. i. e. a short. If it trips, it is either faulty or there is a problem. If the moisture in the cable is causing the RCD to trip then great, better that then when you grab it when wet and get a shock :o

An eye for an eye only ends up making the whole world blind.

Mahatma Gandhi

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To test out the Electrical system

Disconnect the hook up cable

turn off 1) van rcd

2)Van the trip switches

 

Reconnect the Hook up cable and see if the house RD trips if so check the lead for connections and moisture, chech the house socket and van input socket for moisture

 

If the above is ok turn on the Van rcd and test / check the house RCD

Turn on 1 trip switch one at a time and check the house RCD for each trip

 

continue with the remaining trip van trip switches unit the problem occurs

 

Dave

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Hello all members. To peterjohn, no has never tripped on site, to alimac I've tried two cables, one I've owned for about a year and the other a new cable ( un-used ) lent to me by a friend who is also a caravaner, to Caravanmedic, your right and I think that I'll try turning off the RCD in the caravan to see if that trips the house again, if it does, I will leave well alone and leave to the professionals and to dreadly & carabiker, I will try your suggestions and report back here soon, many thanks, Gingerbreadman

Edited by gingerbreadman

PAUL, 2005 Mitsubishi Shogun Warrior 2. 5TD, Towing A 2005 Bailey Pageant Provence .

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OK, have followed some of the suggestions and here are my findings. Rcd off in caravan, attach lead and no trip in house . . switch on Rcd in caravan ( other trips on caravan switchboard in off position ) no trip in house . . switch on breaker for heating and fire, no trip in house . . finally switch on breaker to fridge and lighting, result is instant trip in house . If I switch this last one back off the charge is getting to caravan without tripping house . Have checked every fuse for failure but nothing, all is well, what is there left ? If I put heating / fire breaker into off and then switch on fridge / lighting then with the caravans Rcd in the on position takes about 3-5 minutes before then tripping the house . . Now I'm confused, Gingerbreadman

PAUL, 2005 Mitsubishi Shogun Warrior 2. 5TD, Towing A 2005 Bailey Pageant Provence .

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If its taking a small while to trip it sounds as if it could a damp or heat issue as CM says could be your fridge element or even condensation in your consumer unit in the caravan . run a 2kw blow heater for a couple of days on low inside and see if you have the problem when it is all warm and dry, ps dont forget to leave a roof-light slightly open on vent to let damp escape.

meandcaravan.jpg.e9cf995ee8c89b08e26d261aa10c0fc4.jpg2008 Bailey Senator Wyoming -2004 green oval Landrover discovery 2 td5-2005 Smart forfour.

 

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Thank you Caravanmedic, just tried to reset the fridge breaker to on and immediately it tripped the house again . Has been fine with this breaker in the off position, so I know your right on the button with your advice, thank you again and will now forward the problem to our service agents and let them know to look at this problem carefully when in on the 12th of January, it now appears case closed, cheers, Gingerbreadman

PAUL, 2005 Mitsubishi Shogun Warrior 2. 5TD, Towing A 2005 Bailey Pageant Provence .

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OK, have followed some of the suggestions and here are my findings. Rcd off in caravan, attach lead and no trip in house . . switch on Rcd in caravan ( other trips on caravan switchboard in off position ) no trip in house . . switch on breaker for heating and fire, no trip in house . . finally switch on breaker to fridge and lighting, result is instant trip in house . If I switch this last one back off the charge is getting to caravan without tripping house . Have checked every fuse for failure but nothing, all is well, what is there left ? If I put heating / fire breaker into off and then switch on fridge / lighting then with the caravans Rcd in the on position takes about 3-5 minutes before then tripping the house . . Now I'm confused, Gingerbreadman

In theory the rcd in the caravan should operate first so ensure this gets properly tested during service, and ask to see the electrical test results.

 

https://www. bailey-parts. co. uk/HandbookDetails. aspx?Model=C08D&Type=S

 

Page 16 shows a 5 amp CB which feeds (if I'm reading the rubbish drawing correctly)

 

1/ The water heater via a 5a fuse spur.

 

2/fridge, usually via a 13 amp socket?

 

3/ Charger/psu

 

4/ mains wall lights.

 

So try isolating all these until you locate the problem. I would unplug the charger first.

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Thank you Caravanmedic, just tried to reset the fridge breaker to on and immediately it tripped the house again . Has been fine with this breaker in the off position, so I know your right on the button with your advice, thank you again and will now forward the problem to our service agents and let them know to look at this problem carefully when in on the 12th of January, it now appears case closed, cheers, Gingerbreadman

Glad its sorted, I assume the fridge is normally left switched off via the selector switch?

 

So it shouldn't trip on a faulty element, unless its a neutral earth fault.

It's probably worth putting some heat into the area as suggested earlier, and don't forget to get the RCD tested.

Edited by xtrailman
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Quote "In theory the rcd in the caravan should operate first so ensure this gets properly tested during service, and ask to see the electrical test results"

 

If the RCD in the house is a 30mA RCD, the same as the caravan then, either or both may trip,they both will see the fault and it depends which is the most sensitive which one trips first.

knarf

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Your house RCD should be 30mA to provide personal protection and the same for the the caravan.

One reason the house may trip before the caravan is that the house wiring and appliances may already have a fair amount of leakage and a low level fault in the van, added to the existing leakage in the house, will be enough to trip the house but not high enough to trip the van.

knarf

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The caravan and boat are the only places where a 30ma trip feeds a 30ma trip all other cases it goes up by a factor of 3 approx so 300ma feeds a 100ma which feeds a 30ma which feeds a 10ma there is also a time normally 30ma trips need to trip within 40ms but the 100ma is often an "S" type and so has a longer delay. However as found out with experience when a worker puts a nail through a cable (was to hang his coat on) it will take out all the earth leakage trips from 30ma right to the 1A with 60 seconds delay so the discrimination in practice does not work.

 

I see you have now isolated problem to the fridge which is good but sometimes we can be mislead. The RCD measures the power in and power out which should be the same if nothing has leaked and if within 15ma to 30ma of each other for a 30ma trip will maintain power. There are some specials like the X-Pole which have lights to warn when approaching point when they will trip and only trip between 90% and 100% of the 30ma but the set limits as between 50% and 100% so can trip with as little as 15ma unbalance.

 

The other major problem is main items only have single pole switching which means you can get a leakage between neutral and earth even when switched off. This is a real problem where for example a sultana has fallen out of a bun being toasted as it pops up causing a leakage path between neutral and earth and while very little current is being drawn the potential difference between earth and neutral is very little so not enough current flows through the sultana to cause the RCD to trip. However when the kettle is used then potential difference between earth and neutral becomes higher so the RCD trips making the user think the kettle is at fault where in fact it is the toaster causing the problem.

 

I am lucky I have a PAT tester and can test each item in seconds to find which one is faulty but without some insulation tester it is very hard to work out which items are faulty.

 

The other big problem is mineral insulation these are hygroscopic and with cookers or the fridge used in caravans the ends can't be fully sealed so can draw in moisture once in they need to be heated to over 100 degs C to drive it out again warming the caravan up a bit will not work. There is a dangerous trick done to remove this water but I am not going to say on here with an open forum what it is. Likely on the 12th the caravan people may use this method the problem being if it gets damp again the problem can return. I would go for a new heater being fitted as too easy for the fault to return.

 

Powering a caravan from a supply already protected with a RCD one can't test the caravan RCD there is a 6 part test three tests but all done both on pos and neg half cycle first is to make sure it does not trip at 15ma second that it does trip at 30ma and third that it trips within 40ms at 60ma so only way to test caravan is with an unprotected supply.

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I believe my house RCD is 40 ma.

 

The plug in RCD I use are 30 ma.

 

Not sure what the caravan one is?

With an old house with TT supply likely house is 100ma although allowed to go higher today likely would use 300ma for main isolator where some circuits are not protected to 30ma like supply to fridge/freezer but other than the specials like fridge/freezer or cooker which if the cable is buried in the wall would need special cable like Ali-tube today all sockets and also lights in the bathroom need protecting with a 30ma trip which will open within 40ms. (since bathroom lights are normally on same circuit as all other lights this means in real terms all items now RCD protected at 30ma or less.) So likely both house and caravan are both 30ma trips. The plug in trips are normally active rather than the passive type used in the consumer unit I have used these to comply with rotating machinery rules. So if a grinder has been latched on when we have a power cut when power is returned it will not start up again until reset button is pressed. However other than that there is no real point in using plug in 30ma trips. There are 10ma trips but finding them is not easy.

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Your house RCD should be 30mA to provide personal protection and the same for the the caravan.

One reason the house may trip before the caravan is that the house wiring and appliances may already have a fair amount of leakage and a low level fault in the van, added to the existing leakage in the house, will be enough to trip the house but not high enough to trip the van.

knarf

Yes your right both the dis board rcbs are 30ma trip, I did think they were 40ma, which means fitting a 30ma plug in rcb to protect my pond pump won't stop my consumer rcb tripping as it did last year while we were away in the caravan!

 

Any suggestions, I know individual rcbos? are the answer, but too expensive for me.

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There is no easy answer to the problem apart from running a dedicated circuit with it's own RCD or assuming you have a split board taking the pump supply from the 100mA side,even that won't guarantee discrimination. To guarantee it you would need to fit a type S RCD to the main cons unit which are time

e delayed. To the best of my knowledge these are only available in 100Ma units and aren't approved for personal protection.

I had a similar problem, as a temporary Heath Robinson workaround I used a 110AH 12v battery coupled to an inverter and a solar panel to charge the battery. I only did it because I had the bits available and I changed the pump when I returned for a 12v one.

knarf

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Thanks Knarf, I'll just have to hope any fault occurs while at home, such as the central heating that failed on Christmas day!

Edited by xtrailman
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You can get 10ma RCD's http://www. amazon. co. uk/Metalclad-Plus-K6211-ALM-2-Gang/dp/B004R9PO88 however the price seems to go a bit mad this one £119. 25 for that sort of money I would be considering a consumer unit change. I have found in the past plug in units but google today and could not find one. However I was told often sold by fish places.

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Thanks for looking Eric, the consumer unit is only a couple of years old so that stays as it is.

 

At near £120 its probably cheaper to replace the freezer meat.

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That was also my thought. At the moment I am undecided as to rip out the consumer units and replace with a model which will take RCBO's or to just swap the two existing RCD's for the X-pole type. I don't know why but seems to come in batches the RCD's will trip once a week for a month or two then go 2 or 3 years without a trip and since nothing changed at home it must be something in the street.

 

I did fit emergency lighting at top of stairs so at least not in the dark when it goes there was also another in garage where the CU is but that one now needs new battery. Some day I will get around to it.

 

Fitted them back in 1992 so been in over 20 years can't remember what it was like before. However http://cpc. farnell. com/pro-elec/inlinercd/rcd-in-line/dp/PL10474?Ntt=10ma+rcd is the only 10ma RCD I can find at reasonable price. At £17. 63 did not really want in-line version but with price difference it would seem the only real option.

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Even if you fit a 10Ma RCD in series with a 30mA RCD it still won't guarantee discrimination,if the leakage is is high enough then the 30 mA RCD will also see the fault and trip as well. The only surefire way is a time delayed RCD at scource, and as far as I can see they are only available in 100mA rating.

knarf

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