# Negative Polarity - Autotrail Miami



## BillyR (Dec 1, 2009)

I have recently bought a Autorail Miami - I am based in Germay and when I have used local campsites my negative polarity light comes on in my fuse box thing. Shortly after that I lose mains power. I don't seem to have a switch to reverse it. And you can't just turn the plug upside down as someone suggested because the campsites I've used, use the blue 3 point plug not the normal domestic 2 point. I hope all that makes sense to someone. Please advise how I sort the problem.


----------



## richardjames (Feb 1, 2006)

You could change the wires round in the blue plug temporarily - just positive and negative!


----------



## Bacchus (Mar 27, 2008)

when I go abroad I take two blue plugs one with reverse polarity saves having to muck about after a long day on the road.


----------



## DTPCHEMICALS (Jul 24, 2006)

As above. Not an uncommon ocurrance

Dave p


----------



## HurricaneSmith (Jul 13, 2007)

We've come across power hookup columns in Europe that have both blue 3 pin and 2 pin outlets, where the blue 3 pin was reverse polarity and the 2 pin was not. 8O


----------



## rupert1 (Feb 13, 2009)

Reverse polarity will not cause you to lose mains power, something else is tripping it. This can only be sorted out by investigating the cause and is near impossible to diagnose from distance. Reverse polarity on modern vans is not a cause for concern, unless you are in the habit of taking electrics apart with power on, which i assume you do not. I gave up bothering about it a while ago and no longer check. However not sure about your van as most do not come with a built in light so their maybe some safeguard that has been added.


----------



## scept1c (May 10, 2005)

Hi Billyr,

When I arrive on a new site I normally use a polarity tester plug to check for electical safety. In case you haven't seen one, it has 3 led lights mounted onto a 13 amp plug type unit. All three lights should be illuminated if everything is ok. The plug has a description of what the different light patterns mean. Have a look here for a description Mains Tester Plug

I agree with Rupert1 that reverse polarity should not really cause a problem in normal circumstances but when I was last in Spain, I visited 4 or 5 sites with bad earth connections which caused some odd occurences.

I have made up a short extension lead with live and neutral reversed at the blue connector to correct the polarity issue when necessary.


----------



## thePassants (Feb 9, 2009)

*Reverse polarity / 'socket testers'*

OK, plug-in socket testers (of the type described in previous post):

They'll detect; L / N reverse, L / E reverse, but not N / E reverse. 
They also warn of the complete absence of E, (or of L!)
So, anyone armed with one of these should not be under the impression that it tests for a 'good' earth, or can vouch for the safety of a circuit.


----------



## Bacchus (Mar 27, 2008)

I agree, for a modern motorhome protected by double pole MCBs there should not be a problem but I've seen single pole MCBs fitted and if you connect up a deffective appliance to a supply with reverse polarity then you could end up in trouble.

I carry out a check using a plug-in circuit tester every time


----------



## thePassants (Feb 9, 2009)

Bacchus said:


> I agree, for a modern motorhome protected by double pole MCBs there should not be a problem but I've seen single pole MCBs fitted and if you connect up a deffective appliance to a supply with reverse polarity then you could end up in trouble.
> 
> I carry out a check using a plug-in circuit tester every time


I'm intrigued now.

Mine is a Belgian model of 2005, and has a Double Pole RCD Isolator, and Single Pole MCBs for each circuit.

I've never seen a more modern arrangement with Double Pole MCBs (presumably a DP RCD too): Has anyone got a picture of a new MHs Distribution Board so I can see what the current (no pun intended) models have?


----------



## Annsman (Nov 8, 2007)

On our 2008 Cheyenne this year we stayed on some sites in Europe where he red warning light came on, so I put my reversed wire connector into the box and hooked up using that. The red warning light stayed on! Everything worked ok though so perhaps you should ask Autotrail why yours is tripping out. They are uually good at answering e-mail enquiries if you don't want to ring from germany.


----------



## Sargent (Feb 1, 2008)

Hi BillyR the loss of power is most concerning as this may be a loose connection somewhere from the inlet plug to the PSU.
It may be worth doing some quick checks on the connections (with the power disconnected) to check all of the terminals and plugs are connected correctly.
If you check the back of the inlet plug first and then the black connector in the base of the PSU this should be a good place to start? if you are struggling or need to talk to someone then please either PM us or ring 01482 678981

Best regards

Ian Sargent


----------



## BJT (Oct 31, 2008)

Reverse polarity should not cause an earth trip , it only a problem with power overload on a single pole circuit breaker.
You might have a neutral/earth reversal situation
I suggest you get one of the mains polarity testers as advised in an earlier reply. They are from Amazon so you should be able to get one on line easily. 
You also need to check both ends of the hook up cable to see if the connections are correct.
Brown - line, blue - neutral, green/yellow - earth.
I suggest you also check the cable for signs of damage, you will need to pull it through your fingers feeling for deep cuts or 'lumps' under the sheathing. Any damage throw it away, after making sure it cannot be used any more, and fork out for a new hook up lead. 
Beyond this you will need to check every power point for damage and faulty connection; but if you are not familiar with electrical installations I strongly recomment you get someone competent to do the job for you.


----------



## thePassants (Feb 9, 2009)

BJT said:


> Reverse polarity should not cause an earth trip , it only a problem with power overload on a single pole circuit breaker.
> You might have a neutral/earth reversal situation
> I suggest you get one of the mains polarity testers as advised in an earlier reply. They are from Amazon so you should be able to get one on line easily.
> You also need to check both ends of the hook up cable to see if the connections are correct.
> ...


As stated previously:

* Socket testers DO NOT detect N / E reverse, and DO NOT confirm the safety of a circuit*

see previous post.


----------



## tony50 (Oct 16, 2007)

BillyR said:


> I have recently bought a Autorail Miami - I am based in Germay and when I have used local campsites my negative polarity light comes on in my fuse box thing. Shortly after that I lose mains power. I don't seem to have a switch to reverse it. And you can't just turn the plug upside down as someone suggested because the campsites I've used, use the blue 3 point plug not the normal domestic 2 point. I hope all that makes sense to someone. Please advise how I sort the problem.


As with another posting today especially with Mains electricity, I would advise you get professional advice ,after all "you are a long time dead " !!


----------

