EHU frustration

Hi there, and "Mia culpa!!"

I guess that we all refer to any trip as an "RCD" out of sheer habit.

However, as most of the providers of EHU's are more interested in not overloading the circuit (more Amps being pulled = More Kilowatts being used = Less Profit) they more often than not install an MCB.

At the moment "Petal" (a 1998 Duetto) is in the garage for new wings so I can't check to see whether AS install RCD's or MCB's or a combination of both.

Anyone out there know the answer please?

Best regards,

Ian

At the moment "Petal" (a 1998 Duetto) is in the garage for new wings so I can't check to see whether AS install RCD's or MCB's or a combination of both.


I've just been out & checked on mine, the main box incorparates an RCD with a 'test' button, plus 3 MCBs so I imagine all A/S's have something similar.

Hi All

Dutto wrote: At the moment "Petal" (a 1998 Duetto) is in the garage for new wings so I can't check to see whether AS install RCD's or MCB's or a combination of both.

My van’s 1997 so around the same era as “Petal” and it has a 30mA RCD feeding 2 10A MCBs.

Dutto wrote:
However, as most of the providers of EHU's are more interested in not overloading the circuit (more Amps being pulled = More Kilowatts being used = Less Profit) they more often than not install an MCB.

To be fair camp sites would have to have some form of current limit on each post. In fact it’s a requirement in the regulations. Where there is a low limit it could be due to the total available current at the site (or they may just be tight).
I think they would have to install both an MCB and RCD. There is a special section on caravans and campsites in the wiring regs (BS7671) so they MUST all conform or face the possibility of a fine - or worse. I can’t check until Monday bit I’d be very surprised if an RCD wasn’t a requirement nowadays.

As a frustrated dyslexic camper (for give any spilling mistakes ) who has to work for a living as an electrician to pay for my camping expiditions.
Trying to keep it simple The electrical supply gives you two forms of protection.

The Miniature Circit Breaker (MCB) This is just like an old fashioned fuse. If you take to much load (amps ) it switches off.

The Residual Current Device ( RCD ) This is a clever switch, it workes as a balance. It measures thr current flow "in" on the live conductor and also measures the current flow "out" on neutral conductor. If they are not the same by more than 30 milliamps it switches off. What it is saying is some of the current is not returning by the correct path so it must be going somewhere it shouldn't.


To find the problem connect lead by its self to the supply if the RCD trips, the lead is faulty. If OK continue. Remove lead from supply, then switch off main switch on circuit board inside motor-home. Connect motor-home to supply if RCD trips problem is between the external socket on the motor-home and the circuit board, dissconect call an electrician. If OK continue make sertain all MCB are switched off. Switch on main switch to circuit board if it trips problem is on circuit board. If ok make certain there is nothing connected in to sockets, switch on MCB for sockets if it trips problem with wiring between circuit board and sockets. I ok switch off mcb to sockets, repeat process for each mcb on its own untill you find the fault,
Hope i made this clear Paul

Thank you to both Jeff and Paul RG - I actually understood that!
I'd even go so far as saying I would now feel confident in doing a little fault finding on my own, if the need ever arose

And thank you to brodco and Ian for their 'discussion' - I didnt have a clue what you were talking about, but it was very entertaining all the same!!

Moira

As nobody else has mentioned it I will. In electrical circles there is the little known thing called a gremlin. It runs around where you cant see it undoing the tiny little grub screws that hold the cable ends into the socket connections. When these are loose they will arc when a load is put on them and cause the trip to cut in. Best to check all your socket connections.
Regards, David

Couple of things on this subject; an RCD trips on current imbalance - so if amps out the black wire is less than amps in the red wire it will trip because of a probable leakage to earth somewhere. An MCB trips on sudden surge of current, dosen't matter where it's going. I would also check all the connections in all the fittings as it is thought that an alternating current can test the screws in the terminals - the original sonic screwdriver before Dr Who invented another one. Also, resistance changes with temperature - lower the temperature and the resistance will reduce, probably not applicable in this instance but relevant in calculations.
Rich..

Its not uncommon for a faulty water heater E.g. Kettle or immersion heater, to cause an RCD to trip, when some current leaks from the heating element into the water through to earth.

Hi,
To get back on topic if the problem only surfaced when the chap switched on the second trip and there was nothing plugged in to the sockets then surely the problem must be in the van wiring or sockets,
Chris V

chrisvesey wrote:Hi,
To get back on topic if the problem only surfaced when the chap switched on the second trip and there was nothing plugged in to the sockets then surely the problem must be in the van wiring or sockets,
Chris V

Qiute right. I explained the operation of the circuit breakers for information, the problem in this case has nothing to do with the load, that is controlled by the circuit breaker on the site pillar. It could be a damp EHU cable or damp in the van's internal wiring, but, something is draining current to earth to make the van's RCD trip out, or allowing a surge which will trip the MCB in the pillar. I would start by shortening the EHU cable by about a foot at both ends then remake the connections, this could eliminate any damp in the cable. If the problem still persists the van electrics should be tested by a competent electrician. There is no absolute way of knowing if the previous owner made changes to the wiring, testing is the only way.
Rich..

Well having had my girl parked on the drive and assuming the problem was the site electrics i plugged her into the house mains today to cool down the fridge and give the battery a boost before my trip away thursday and everything was lovely UNTIL i was emptying out the cupboard and realised the socket circuit was still off (at this point only fridge and the battery charger in opration from mains) so i switched that circuit on (nothing plugged into sockets and they switched to off on each socket) less than 30 second later i heard a click and everything went off. What has concerned me the most is this time it didnt trip the van circuit breakers but the ones in the HOUSE!! having re set the house trip switch i turned socket circuit off and everything was fine, I then turned the battery charger off at the switch under the cupboard and switched the socket circuit back on and NOTHING Tripped. it seems i can have the battery charger on but not the socket circuit, or the socket circuit but not the charger :-(

The reason your house tripped is probably because it is more sensitive, there are rating notices on these items. It's sometimes easy to get complacent with vans because of the 12v wiring, however, the 240v circuits should be considered as hazardous as those in your house. Bearing that in mind what would you do if your ring main constantly tripped for no apparent reason? The answer is to pull out all the plugs, isolate the wiring and test each component and cable to find where the current is being lost. The conditions you describe are under no apparent load; the either or situation should not make any difference unless the battery charger is always on - in which case switch it off. The time element would lead me to think there could be damp in the wiring somewhere or insulation is breaking down. Sorry, but not easy to diagnose from a distance.
Rich..

Harper22 wrote:Well having had my girl parked on the drive and assuming the problem was the site electrics i plugged her into the house mains today to cool down the fridge and give the battery a boost before my trip away thursday and everything was lovely UNTIL i was emptying out the cupboard and realised the socket circuit was still off (at this point only fridge and the battery charger in opration from mains) so i switched that circuit on (nothing plugged into sockets and they switched to off on each socket) less than 30 second later i heard a click and everything went off. What has concerned me the most is this time it didnt trip the van circuit breakers but the ones in the HOUSE!! having re set the house trip switch i turned socket circuit off and everything was fine, I then turned the battery charger off at the switch under the cupboard and switched the socket circuit back on and NOTHING Tripped. it seems i can have the battery charger on but not the socket circuit, or the socket circuit but not the charger :-(

Sorry to be a bore but I think you definately need to check the connections in ALL your 240v sockets in the van.You have a loose contact somewhere by the sound of it.

d.l.hunter wrote:

Harper22 wrote:Well having had my girl parked on the drive and assuming the problem was the site electrics i plugged her into the house mains today to cool down the fridge and give the battery a boost before my trip away thursday and everything was lovely UNTIL i was emptying out the cupboard and realised the socket circuit was still off (at this point only fridge and the battery charger in opration from mains) so i switched that circuit on (nothing plugged into sockets and they switched to off on each socket) less than 30 second later i heard a click and everything went off. What has concerned me the most is this time it didnt trip the van circuit breakers but the ones in the HOUSE!! having re set the house trip switch i turned socket circuit off and everything was fine, I then turned the battery charger off at the switch under the cupboard and switched the socket circuit back on and NOTHING Tripped. it seems i can have the battery charger on but not the socket circuit, or the socket circuit but not the charger :-(

Sorry to be a bore but I think you definately need to check the connections in ALL your 240v sockets in the van.You have a loose contact somewhere by the sound of it.

Hi there,

I concur; and also advise that you do it as a priority and before using the van on EHU again!

Best regards,

Thanks to everyone thats contributed, sounds like i need to have a good old poke about on the connections hopefully be able to have a good look this weekend while im away. Fingers crossed its something as simple as a loose connection but will keep you all posted

Regards

Neil

Bradco is right! You must also remember that with a thin, ie thin enough to give significant resistance, cable that there will be a voltage drop 'across' the cable. This will mean your device will not see the full 230v. NB must say 230v not 240v these days or the Eurocrats will probably shoot you.

For 230v you never really need thick cable, unless you are drawing lots of current. Any reasonable cable will have a tiny resistance.

Funny enough the situation is much worse for 12v systems and if anybody wants me to explain it, then I will. But it is boring.

mccormw wrote:
For 230v you never really need thick cable, unless you are drawing lots of current. Any reasonable cable will have a tiny resistance.

I agree but interestingly, (as I read it) there is a minimum size of cable required by the regulations! If I am reading it correctly there are certainly loads hook up cables on the market that don’t comply. Extract from 17th edition wiring regs below;

Section 16.13-Electrical installations in caravans and motor caravans

Regulation 717.52.1

Flexible cables for temporary supply to unit to have conductor size not less than 2.5 mm and be of typeH07RN-F (BS 7917) or equivalent.

In any case there is lots of useful information here for anyone interested;
[You must be registered and logged in to see this link.]

Many thanks to everyone who replied on this subject im VERY pleased to report the problem is solved.

Although not quickly or easily. The main trip box under the cooker was showing some signs of blackining on the rcd units and unfortunately at short notice i couldnt locate the matching ones. I had an electrician (the father in law) change the whole unit for me so whatever happens its now up to date and the rcd's can easily be found and replaced if needed HOWEVER this did not sort out the problem.

After getting a test meter that sent 500v through the cables we narrowed the problem down to a short in the cable from the consumer unit to the first plug (the one by the sink) after taking the fridge vents off and the inner panel of the cupboard below the cooker as well as the socket back boxes out of the wall panel we managed to pull a new cable through the void areas to re wire.

As soon as the old cable was out it was OBVIOUS what the problem was, the cable had been fitted over the wheel arch area of the van and wedged between that and the HOT water pipe. after 14 years of use the once round white cable was worryingly BLACK and triangular in a 2ft section where it had been wedged. My guess is the combination of the hot water in the pipes and the vehicle body heating up in the summer (anyone remember those???) had caused the cable to heat up and melt the plastic protective sleves around the bare wires as you could indeed see the copper cable in a few areas.

cable replaced and run well away from anything giving off heat and what do ya know all working like a dream :-) hope this helps anyone else out there that may have issues in the future

Neil

Harper22 wrote:
cable replaced and run well away from anything giving off heat and what do ya know all working like a dream :-) hope this helps anyone else out there that may have issues in the future

That's useful to know. Sounds like the sort of problem that could occur in any similar van. Glad you found it.

Brod.

my worry is that if my cable was wedged on the harmony then how many others were built the same, I know all models are different but im guesssing wiring looms were ran the same :-S

brodco wrote:

Harper22 wrote:
cable replaced and run well away from anything giving off heat and what do ya know all working like a dream :-) hope this helps anyone else out there that may have issues in the future

That's useful to know. Sounds like the sort of problem that could occur in any similar van. Glad you found it.

Brod.

Glad you got it sorted eventually................................just started worrying myself now!!

PB

Sorry bout that boxer, Im hoping mine was a freak incident. If you undo the 4 screws in the cupboard panel and lever it forward there should be just enough slack on the cables to maybe get a torch in and see if yours are wedged too, Im just glad the short was top (heater pipe) side and not metal side

peugeotboxer wrote:Glad you got it sorted eventually................................just started worrying myself now!!

PB

Harper22 wrote:Sorry bout that boxer, Im hoping mine was a freak incident. If you undo the 4 screws in the cupboard panel and lever it forward there should be just enough slack on the cables to maybe get a torch in and see if yours are wedged too, Im just glad the short was top (heater pipe) side and not metal side

peugeotboxer wrote:Glad you got it sorted eventually................................just started worrying myself now!!

PB

Thanks for headsup......will check as soon as.
Will report back.

PB

Hi Harper22,

Glad you found the problem, and is now all sorted

Brian

Whilst the heat would not have helped, electrical cable shouldn't be unduly affected by the temperature of a hot water pipe. Its much more likely to be the friction of parts rubbing together minutely but constantly with vehicle movement and temperature variation. If the cable is warm then it will be softer and possibly more prone to being worn.

Try to ensure cables and pipes are not 'trapped', but clipped out of the way where they are free to flex a little as required but held away from sharp edges and not wedged between fittings.