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PMS4 Power Supply, MCB constantly tripping.


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Whilst in Wales our travelling companions had issues with their power supply, in that the 10a MCB for the sockets kept blowing. We unplugged everything and switched everything off but no change. Even when the mains hook up was disconnected the MCB would not latch in the on position, just kept flicking back to off. 

 

My thinking is that the MCB is faulty, is that correct, or do we need to start chasing down a wiring issue?

 

Can the MCBs in this unit be replaced, the thing is riveted together, though that will not stop us getting into it if necessary. 

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If the MCB won't reset with no mains attached then it is faulty. I'm not sure how they come out but have slwsys assumed they are fitted like household ones. 

You don't state your friends caravan make, model and year. 

Graham

 

Unless otherwise stated all posts are my personal opinion 

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Google refers me back to old threads in this forum, indicating the MCBs are marked Hager. They are readily available in many places. The 10A MCB may be the fridge MCB. 

 

Removal of the MCB can only be done with the mains disconnected and should only be done if you know what you are doing. If not, get an electrician to do it. 

Graham

 

Unless otherwise stated all posts are my personal opinion 

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Er no, the 10A MCB will feed the 'public' 13A sockets but not usually the fridge (it only draws about 170W even for a tall one!) The fridge, heating, microwave, and cooker will all be connected via a 13A plug and socket hidden in the depths so that in the even of a fault removal is simple.

But we are being hypothetical here as if the MCB will not stay on with no electricity running through it it is faulty - period. Hager are a good brand so if it is mechanically faulty you are unlucky as against the horrible nasty Chinese things fitted in many caravans which drop out as soon as you blink at them.

In theory these are DIN-rail mounted units so should be interchangeable but in practice the part of the unit that protrudes through the front of the casing may vary in size by means of the ratio of the protrusion to the depth of the main body, or the width or height of the protrusion which may mean they may not fit snugly. The RCD on our last caravan (Peg 462) was a horrible Chinese and kept tripping mechanically during travel. I found a Schneider unit of better rating which cost me £22 but was a perfect mechanical fit. However the distribution of the mains out from the RCD to the input of the MCBs was by means of insulated busbars and as the Schneider outlet position did not match the busbars (nor could be made to) I had no option but to change the busbars to wires (flex) which did the job perfectly.

Schneider incidentally is what used to be MEM in the UK.

Edited by Woodentop

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Thank you for all the help, it is really appreciated.

 

4 hours ago, WispMan said:

You don't state your friends caravan make, model and year. 

 

Apologies, like ours it's a 2005 Lunar, there's (my sister in law) is an Astara 540 , ours a Freelander 640. As such we have most of the same appliances etc, including PMS.

 

Interesting the cover of theirs is riveted together, whilst ours is secured with self tappers and sprung washers, which I'm guessing means ours has been serviced or repaired at sometime, and is the likely way of reclosing theirs. 

 

I'm happy enough changing an MCB as long as I can get a like for like fitment. Their mains unit has two 10a mcbs side by side, one for the sockets which is the faulty one, and another for something else, I can't quite remember what. 

 

We're off to our holiday cottage for a couple of days next week, after which I'll go and remove the offending item and fit a replacement. I'm assuming it's a type b but they are so easily available I'll remove the faulty one first to check. 

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Do come back and let us know the outcome so future members can learn from other people's problems. 

Thanks

Graham

 

Unless otherwise stated all posts are my personal opinion 

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Indeed I will, I'll get a few photos as well if I can. 

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Excellent! 

  • I agree completely 1

Graham

 

Unless otherwise stated all posts are my personal opinion 

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