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Ken955

Power tripping with nothing connected

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van is a 2004 Ace Jubilee 

 

On holiday at the mo, been fine for 11 days but for past 2 days the power is tripping at the rcd on the pole or on the internal box. This happens only when the 3rd trip is on, (nearest the rcd) which seems to be the mains sockets.

I can leave the fridge, water heater and lights on fine, but even with all the sockets empty it still trips. Only change is different site and the night before I had the electric heating on. (12v fan side had a blown fuse which I replaced) Van is new to us so don't know its history. Have changed mains cable and pole.

I have switched off the heating and toggled the space heater switch.  

It also isn't constant! It tripped last night, just after 5pm, reset trip, turned off socket mcb, and power was OK all night. Switched sockets back on this morning and cooked breakfast fine, tripped again this pm.

Only thing I can think of is a earth leakage from the heater, but how do I disconnect it?

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Do you know what AH your site EHU is providing?

Site AmpsCalculation:-

16A 230V x 16A provides up to 3. 68kW

10A 230V x 10A provides up to 2. 3kW

5A    230V x    5A provides up to1. 15kW

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Yes, you most likely have some earth leakage somewhere. Possibly water (road spray?) getting into damaged insulation or in the heater. Time for an electrician with some test equipment I think.

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Is the fridge plugged into a 13A socket? Doesn't it go off with mains sockets? 

I mention it as if you've discounted the water heater, the fridge heater element is another candidate. It might of course be a combination of appliances that exceed a leakage threshold.  

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As said have you checked your supply Amperage ?  

 

I would start by trying a different EHU hookup cable if you can to see if any difference and if still persists as said unplug everything then try pluging things back in one at a time .

 

Possibly also the MCB s themselves if they are the cheap Chinese make F&S which would require replacing .

 

 

 

Dave 

Edited by CommanderDave

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Do you have a plug in the kitchen area? If so, check under the cooker / wash basin for an in-line connector. If you find one, disconnect and check for water ingress. If found, dry out with kitchen towel and/or blow dry. *

 

Before I hermetically sealed that connector and sealed the gap between the work surface and the cooker, about an hour after I washed up each night my RCD would trip!

 

*obviously make sure the sockets MCB is tripped before you do this!

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I would try opening up each socket in the van and checking the tightness of the screws holding the flex inside (after diconnecting the ehu).

Make sure you get all the sockets including any hidden in cupboards for microwave, oven etc.

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9 minutes ago, hp100425ev said:

I would try opening up each socket in the van and checking the tightness of the screws holding the flex inside (after diconnecting the ehu).

Make sure you get all the sockets including any hidden in cupboards for microwave, oven etc.

One could try a socket tester for not much over a fiver from ToolStation ( spend a tenner for free delivery)...

 

IMG_0546.thumb.JPG.008dd4e38bc77e9f144a7238b02958f5.JPG

 

Most faults will will be detected.

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Swift manuals / schematics are downloadable for 2004 MY Ace caravans. ..

 

MCB1 is blown air heater and sockets (10A)

MCB2 is water heater and mains lights (6A)

MCB3 is fridge and charger (6A)

 

Needs a methodical approach to determine where the earth leakage is coming from and exceeding the trip rating of 30mA.

A mobile tech will have the needed kit to do so.

 

The suggested plug in tester will be of no use whatsoever.

Edited by Rodders53

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Many suggestions but not the couple that matter. Several items in the caravan are also fed from 13A sockets, usually the electric element of the room heating, and the microwave. The fridge can be ignored as it is fed from the lighting supply as likely will be the water heater. As the OP said that he had used the room heating the night before and there is now a problem that is where I would start.

However two other points about the RCD.

Firstly it only protects items downstream, so if the caravan unit is tripping there is nothing wrong with the EHU or supply pillar. The fact the the pillar RCD is tripping sometimes is purely a time issue, the fact that the caravan RCD is tripping says that the fault is in the 'van.

Secondly it is not unusual for RCDs to become physically defective over time and be susceptible to tripping for no apparent reason. If the original is one of those horrible Chinese things I would replace it with a known branded unit. The Schneider (as was MEM) units are almost exactly identical in size to the Chinese ones - it is the width that matters - for which any make with DIN-rail mounting and of  25A or more switching, 30mA trip, and Type A or AC rating will do. Expect to pay around £25 or less. Note that unless you are competent to do it you should get an electrician in (doesn't need to be a caravan tech, just an electrician) as it will probably be necessary to replace the distribution busbars in your power box with cables - I had to do that in our last caravan - as the RCD outlet connections may not match positionally.

 

Edited by Woodentop

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So if those horrible MCB Chinese things have now lasted some 14 years why not replace like with like to save further expense and modification unless of course the OP  intends to keep the caravan for a long long time.

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17 hours ago, Woodentop said:

Many suggestions but not the couple that matter.

I could take offence at that!  I feel my post provided useful info to the OP. .. that the manuals and wiring diagrams are available for download from Swift;  and confirming that the sockets and heater are indeed on the same MCB circuit.

22 hours ago, Ken955 said:

Only thing I can think of is a earth leakage from the heater, but how do I disconnect it?

That will involve at least partial stripping down of the power distribution panel to access the wiring and connection plug/sockets.   One 9-pin connector will disconnect the space heater and mains lights (see the service manual Jubilee Range wiring diagram for the details).

 

Note the age of this caravan means SP MCBs are used. I'd therefore expect that the heater switch on the panel is also single pole only?  Thus a fault to earth on the neutral of fire or sockets will still trip the (double pole) RCD.   {The same Swift manual shows the RCDs to be Hager brand, used by Plug in Systems on their ECM 4 unit, if the drawing is correct}.

 

The likelihood is that one or both heating elements in the fire have an issue (being mineral insulated, damp can get in at the seal where they connect to the supply wiring).  Finding that out / proving it will require the rear of the fire stripping down to access the connections for testing.   The issue may need an insulation tester to diagnose, as a simple multimeter may show 'no fault'.

 

A decent mobile caravan tech would have the needed meters and knowledge to do this with ease;  skills (and kit) the OP may lack?  A good mobile tech would also have the kit to test the caravan RCD is still within spec (or demonstrate it's not).

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On 06/09/2018 at 18:42, happynomad said:

 

One could try a socket tester for not much over a fiver from ToolStation ( spend a tenner for free delivery)...

 

IMG_0546.thumb.JPG.008dd4e38bc77e9f144a7238b02958f5.JPG

 

Most faults will will be detected.

 

Slight problem with this, it wont do anything without the power on and the power trips straight away!

 

Leave it in the cupboard with the chocolate teapot.

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1 hour ago, AJGalaxy2012 said:

 

Slight problem with this, it wont do anything without the power on and the power trips straight away!

 

Leave it in the cupboard with the chocolate teapot.

That's not quite what the OP said now is it unless I've completely misunderstood the bits, 'It also isn't constant' and 'Switched sockets back on this morning and cooked breakfast fine, tripped again this pm'  but don't let that get in the way of your very technical and detailed reply.

 

On 06/09/2018 at 15:33, Ken955 said:

It also isn't constant! It tripped last night, just after 5pm, reset trip, turned off socket mcb, and power was OK all night. Switched sockets back on this morning and cooked breakfast fine, tripped again this pm. 

 

If I need any electrical advice, would you mind awfully if I messaged you directly? 

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On 6 September 2018 at 17:11, CommanderDave said:

Possibly also the MCB s themselves if they are the cheap Chinese make F&S which would require replacing .

 

 

 

Dave 

 

I had the same problems on my previous caravan, a 2007 Bailey Bordeaux, which had F&S MCB's. If they are F&S then the only solution is to change them. I had difficulty in finding replacements that were the same physical size to fit in the box.

Brian

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1 hour ago, happynomad said:

That's not quite what the OP said now is it unless I've completely misunderstood the bits, 'It also isn't constant' and 'Switched sockets back on this morning and cooked breakfast fine, tripped again this pm'  but don't let that get in the way of your very technical and detailed reply.

 

So he did, I hadn't spotted that bit, even so, the tester wont really identify any issues other than an incorrectly wired socket which is unlikely.

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30 minutes ago, AJGalaxy2012 said:

So he did, I hadn't spotted that bit, even so, the tester wont really identify any issues other than an incorrectly wired socket which is unlikely.

I agree it is unlikely but my suggestion of using a socket tester was a response to a post suggesting that the OP could/should take each socket apart to check the wiring. ..  its all in the context really but. ..

 

. .. as it seems to be happening at a particular time of day (PM) perhaps the op should be looking for a timer event or the routine connection/switching on of a particular item or somesuch.   On the face of it there is no possible reason for a circuit to routinely work as designed in the mornings but to not work in the afternoons other than something  'faulty' being introduced into to the circuit.

 

I believe the OP said it was variously the bollard or his 'sockets' that trip.  We have the bollard trip if the Alde is on 2Kw and the kettle and the coffee machine are both switched on.  (It still happens :o)  I can't ever remember any of the MCBs tripping though?  

 

It will be interesting to see what the outcome is with this one.

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6 hours ago, happynomad said:

I agree it is unlikely but my suggestion of using a socket tester was a response to a post suggesting that the OP could/should take each socket apart to check the wiring. ..  its all in the context really but. ..

 

. .. as it seems to be happening at a particular time of day (PM) perhaps the op should be looking for a timer event or the routine connection/switching on of a particular item or somesuch.   On the face of it there is no possible reason for a circuit to routinely work as designed in the mornings but to not work in the afternoons other than something  'faulty' being introduced into to the circuit.

 

I believe the OP said it was variously the bollard or his 'sockets' that trip.  We have the bollard trip if the Alde is on 2Kw and the kettle and the coffee machine are both switched on.  (It still happens :o)  I can't ever remember any of the MCBs tripping though?  

 

It will be interesting to see what the outcome is with this one.

Agreed, using a megger should be able to track it down fairly quickly using higher voltage to stress wherever the insulation is failing.

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3 hours ago, AJGalaxy2012 said:

Agreed, using a megger should be able to track it down fairly quickly using higher voltage to stress wherever the insulation is failing.

"megger"! That's the word I was searching my head for when I wrote the second reply to this thread!

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I had same problem, I tried all the simple tests, realised I needed an insulation tester (Megger) however did not have one with me, and day latter able to turn power on. On return could not find my Megger so I bought a really cheap digital insulation tester off internet brand new for £35 it took about 6 weeks to arrive, and what ever had caused the fault had clearly dried out and I could not find a fault, found my megger and same result, no fault found.  This is the one I bought there are others around the same price, compared results with my megger and they are about the same, once I used the correct lead connections, the two outer ones, I will guess in my case damp in the toilet area where the consumer unit is inside the wardrobe, possible leak on shower which was used trip before.

 

I would say get some of those bags which dry out things, try to manage without the power for a day then try again. Wife says cloths in wardrobe were damp, and she has a unit which collects the water, since half full clearly there is some damp some where.

 

The megger (Trade name for insulation tester like Hover for vacuum cleaner) will show a fault, but it does not find a fault, to find the fault you need to isolate areas then test, so it may help you find it is for example the fridge, but you would need to disconnect the fridge to test it first.

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11 minutes ago, ericmark said:

 

I would say get some of those bags which dry out things, 

Silica Gel?

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Not sure if Silica Gel or not, I thought you had to dry out Silica Gel, the bag she had let water run into a bag beneath it. It may be simple salt.

 

The worry with insulation failing is it causing a track, would get it with old cars on the distributor cap, only cure was new cap or drill a hole through the track. So when ours went wrong we left the power off with heating on for 24 hours before we tried it again.

 

But even at 1000 volt can't detect a problem now. This is why we use a special meter, it tests with 500 volt normally, my new one has option 250, 500 or 1000 volt, our simple multi-meters use at best 9 volt so are not much good detecting this type of fault.

 

You can get ammeters that can detect the leakage also, my PAT tester has one, so using a 13A to 16A adaptor I can plug in the whole caravan and test it, however although it will show when 15 mA is leaking to earth, it will not show much above that as the RCD will trip.

 

My son is also an electrician and like me at work he has to use the works calibrated test gear, so we don't need our own test set, we however did have one we shared, three meters in it, the low ohm (has to use at least 200 mA) and the insulation tester (must use 500 volt on one setting) is one meter, the prospective short circuit current and loop impedance was a second meter,  and third tests the RCD giving a time reading in milliseconds as to how long it takes to trip. These test sets cost around £500 for a cheap one, so are well over what some one not in the trade would want to pay out.

 

However there are some cheap versions, the EZ150 from Martindale plug in tester did a basic loop test, but think these have been withdrawn, the socket & see SOK36 and the TIS 1005 also do a loop test. The linked one shows Loop Detection Ranges <1. 8Ω, 1. 8Ω - 92Ω, >92Ω however for a 32A ring circuit the pass is 1. 37Ω so for domestic it will show faults, but does not prove good.   However a B16 MCB as used in a caravan has a pass limit of 2. 7Ω however that is line - neutral and the tester tests line - earth where it is considered with a TT supply using a RCD as protection 200Ω is the limit as above that it may not be stable. So since TN-C-S is not permitted on caravan sites, these testers could be very misleading, it will likely show "Urgent Check" on every caravan site. There are still good value at £36. 66 far better than the type without loop or RCD testing, I will assume it does not record the time, but it least you know it works, however you have to be aware of the limitations on these super cheap testers.

 

The insulation tester I linked to only does insulation and voltage, most also test low ohms as well, but it is super cheap.

 

As an electrician I had to attend a 12 week course 3 hours a week and take a special exam to show I could inspect and test, this was on top of my training as an electrician, clearly with a forum post we can't tell you all you need to know, the 500 volt from the insulation tester may not kill you, as current is limited, however it will likely cause some words to be uttered that should not be used in front of your maiden aunt. In the main it's not the person using the device who gets the shock, but some one who is touching some thing made live with it. (I have to admit some times intentional) However electric shocks are not fun, I went into a work shop where I could see some one had wired up an impulse mag to a vice, clearly designed to give visitors a shock, I stood hand on vice, and the guy came to talk to me, and as I saw his hand go to the mag I touched back of his neck, that was last time I every gave some one an electric shock for fun, I thought I had killed him. It was an ambulance job, although he had recovered by time it got there. The impulse mag went back into stores and no one in that workshop every tried doing tricks like that again, as I said including me.

 

I am not saying don't use it. Just be careful and don't ever leave it where kids can play with it, as kids are kids and they will think giving some one a shock is funny.

 

 

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