caravan Re-wire & Consumer Units

[Eddtheduck]

Hi All,

You may or may not be aware that my recent caravan purchase has some dodgy electrics (see the adventure temporary stalled post in welcome)

So the decision has been made to re-wire the caravan, now talking the the electrical engineer at work they have advised the following:

Tri-rated cable

1mm for lights with a 6 amp breaker
2.5mm for sockets with a 10 amp breaker

The main breaker would be 25 amp.

There will be 3 or 4 240V lights probably LED spots so should be OK with the fuse and cable etc.

There will be probably be no more than 4 x single sockets and 3 x double sockets with at least 3 sockets having the usb connections on the front, so the cable and fuse for this should be OK

I also have a outside plug that's not IP rated so I am going to change this for the correct one, now do I run the outside plug off a separate breaker as in the future all the cooking will be done in the awning and we would possibly have a microwave, George Foreman electric bbq and kettle and a couple of lights etc?

Do I also run the fridge off its own breaker? if so what amp do I go for on the breaker? as we would only use this on 240v? I'm going to remove the gas cooker and buy a travel cooker and run a separate bottle in the awning if need be?

If i can run the fridge and outside socket off the 10 amp circuit then I will buy the below consumer unit if its recommended run the fridge etc separate what unit do I go for?



Thanks for your help.

Ed

 

[Parksy]

Hi Edd
I'm not an electrician but as I understand it, Tri Rated Cable is the sort of fire retardant cable used in switchgear etc.
The only thing that I would add is that 230v caravan wiring must be of the flexible multi-core type. I'm not sure if Tri Rated is single or multi-core but single core cable is more likely to become loose at screw terminals under vibration.

 

[Eddtheduck]

Sorry my mistake it's tri-core or multi-strand

 

[Guzzilazz]

In the marine world, perceived wisdom is Arctic grade cable...

 

[ProfJohnL]

There is a section in the IEEE that concerns itself with caravan wiring. I suggest that rater than try to design your own system that may not comply, have your electrical fitter consult the regulations. The NCC has published (many years ago) a short form version of the regulations that touring caravans should conform to.

 

[Eddtheduck]

Thanks for the advice everyone it's much appreciated.

The wife is keen to go away for the weekend so we are going to temporarily use the 3 plug hook up lead we have for the trailer tent.

The 12v all work apart from the fridge which could be the fuse but as there 12v fuse box has no indication on what runs what I'm unsure what the problem is.

I will re-wire the 12v when doing the 240v.

 

[ProfJohnL]

Hello Edd,

Because this is an anonymous forum, I have no way of knowing what skills or professional qualifications you may have. So my responses are aimed at providing information that will inform the least exprienced reader.

When it comes to working on gas and electrical systems, I am particularly careful about offering advice, because of their potential for causing harm or even death if they are not managed correctly.

In a normal domestic or industrial environment, it's easy because legally the work must be carried out by a professional with the correct tickets for systems they're working on., But touring caravans are an anomaly, because they have been specifically categorised and have some consessions within the regulations. I have no idea why they're exempt from some aspects, in my professional view and from practical experience it's a dangerous freedom, because I have been called into deal with many caravans were problems from incompetent work has caused an issue and cases where serious problems, and major injuries have occured.

However, whilst the regulations may permit the owner of a private touring caravan to undertake work on their own caravan for their own use, only the owner, and no other unqualified person can do so, so that excludes friends or even relatives!

If the caravan is to be used by anyone other than the owner, the owner effectively becomes a landlord, and it is their duty to ensure all systems are installed and functioning correctly.

It is worth bearing such things in mind before undertaking work on your caravan. It's not so much yourself but for others such as your family, and of course anyone you may well the caravan to.

Caravans unlike sedentary houses are a very physically challenging environment, because of the stresses induced through towing, which do severely test connections and the fixing of appliances.

A substandard connection may retain enough integrity to continue to work in a house, but due to vibrations induced through towing, and the more prolonged effects of cornering, accelerating, and braking, the systems in a caravan are put under much greater stress, and unsatisfactory workmanship has a much greater potential to become hazardous.

 

[Eddtheduck]

Thanks for your help

I'm going to treat the caravan re-wire like if it was a house.
I'm aware of what I can and cannot do in the eyes of the law so was going to run the cable in and only connect to the lights and sockets.

Once this has been completed I was going to either get this inspected and tested and get the relevant report signed off as safe by a caravan electrician/ service engineer or a normal house sparky that way i can be confident that it is 100% safe and legal.

On the gas side of things I'm taking all the gas out and water heater as I would never use this or the fridge on gas. It easier to just boil the kettle to wash up if need be and the caravan doesn't have a shower.

Thanks

Ef

 

[Woodentop]

There is a section in the IEEE that concerns itself with caravan wiring. I suggest that rater than try to design your own system that may not comply, have your electrical fitter consult the regulations. The NCC has published (many years ago) a short form version of the regulations that touring caravans should conform to.

For the record Prof it is and has been the IET for a decade or so. I was FIET until I retired and so no point in paying well north of a ton to be able to put four letters after my name to no avail - so I resigned!

 

[otherclive]

Isn't the IEEE still in existence and continuing to publish technical codes adopted throughout the world?
Being a simple Mechanical Engineer I suspect it is the now defunct IEE being discussed who did input into British Standards.

 

[ProfJohnL]

I sit corrected, The wiring regulations are now issued by the IET. It is 20 years since I retired from doing electrical installation service work.

But my point is still valid.

 

[colinbal4]

Thanks for the advice everyone it's much appreciated.

The wife is keen to go away for the weekend so we are going to temporarily use the 3 plug hook up lead we have for the trailer tent.

The 12v all work apart from the fridge which could be the fuse but as there 12v fuse box has no indication on what runs what I'm unsure what the problem is.

I will re-wire the 12v when doing the 240v.

I asked a question on here about my fridge, and somebody replied to say that the fridge is not supposed to work off 12v battery.

They said it was 240v, or 12v connection to car whilst towing, or gas, and that the 12v feed from the battery was only to power the light inside the fridge.

I've yet to test whether that's true or not, but I'll go switch it onto battery now and see if it starts kicking out hot air from the vent outside.

 

[Eddtheduck]

If you could please let me know what happens that would be great.

 

[ProfJohnL]

Caravan fridge's do NOT use the caravan battery to cool them. There is a very simple reason for this:- the fridges 12v element will consume about 10Amps of current. That will discharge the battery in a few hours.

Caravan should be wired to only use 12V power for cooling, when the tow car is connected and it's alternator has sufficient capacity to run the fridge.

Modern fridge's do use the caravans 12V battery supply to power it's control circuit, but not to cool it.

FYI, UK mains power is quoted as nominally 230V.

 

[ProfJohnL]

...On the gas side of things I'm taking all the gas out and water heater as I would never use this or the fridge on gas. It easier to just boil the kettle to wash up if need be and the caravan doesn't have a shower.

Thanks

Ef

It is your choice whether to use gas or not, but I do advise that stripping out the gas system may be an unwise move.

Trying to rely just on mains 230V power sometimes is not enough, because you are limited to an absolute maximum of 16A where that is actually available, and less on some other sites.

16A equates to a maximum power of only 3.68kW. if yo have your electric heater running at 3kW and you turn your kettle on, you will exceed the available current and it will trip the incoming supply MCB.

When you consider all the items that will load the available incoming supply, fridge, 12V power supply and battery charger, lights, water heater, space heater, any form of cooking appliances, it all adds up, and you will see how easily it will be to exceed the available power.

Whilst many caravanner do use mains 230V to run many smaller powered items, they still tend to use gas for cooking, and heating.

Without the gas as an option, you will need to be very vigilant about what is turned on at the same time otherwise you will not be popular with site staff who will constantly be resetting your site power breaker.

 

[emmerson]

You beat me to it Prof! I'm amazed that no-one has picked up on that before.
Edd, as the Prof has said, if you use all those appliances, you're not only likely to trip the breaker, you'll probably upset a lot of other caravanners when you put the site power out!
The caravan is not a house, and cannot be used as such. Large sites may well have 16amp power, but they are the exception. Some, especially in Europe, or some British CL and CS sites might only have 6 amp or even less, then you won't even be able to boil a kettle.
Keep the gas, mate.

 

[Craigyoung]

I am with Parksy and emmerson on this one too , if your remove your gas feeds and solely relying on electric what happens if your charger goes and you have no electric like what happened to us in France , we ran on gas for a few days till we got fixed but if you do that you're a bit stuffed completely plus we use our gas for cooking in the oven for the kids !?

 

[otherclive]

We mostly use the gas for cooking, and electric hook up for heating and hot water, but I always make sure that I have a gas bottle available and before each trip test the heating and hot water on gas in case its required as a fall back.

 

[colinbal4]

My fridge does cool off battery, it's been on the last 2 1/2 hours since my post earlier, having not been switched on for weeks, and the freezer compartment is ice cold, whereas it was at room temperature 2 1/2 hours ago. Cant really feel any heat kicking out the vent outside like you do when it's on 240v, but it is quite a warm day so I might just be unable to feel the difference on the back of my hand.

240v hookup disconnected, 12N and 12S plugs disconnected, master 12v switch on, switch on front of fridge set to the battery.

Maybe it would drain the battery very quickly, I have a Numax 105ah class B, but it definitely does work.

Not that it will ever run off the battery except perhaps when parked up at motorway services with car engine off.

It's an Electrloux Dometic with a front switch like this

 

[otherclive]

My fridge does cool off battery, it's been on the last 2 1/2 hours since my post earlier, having not been switched on for weeks, and the freezer compartment is ice cold, whereas it was at room temperature 2 1/2 hours ago. Cant really feel any heat kicking out the vent outside like you do when it's on 240v, but it is quite a warm day so I might just be unable to feel the difference on the back of my hand.

240v hookup disconnected, 12N and 12S plugs disconnected, master 12v switch on, switch on front of fridge set to the battery.

Maybe it would drain the battery very quickly, I have a Numax 105ah class B, but it definitely does work.

Not that it will ever run off the battery perhaps when parked up at motorway services with car engine off.

It's an Electrloux Dometic with a front switch like this

If you go on a longer ferry crossing be sure to disconnect your cables then, otherwise you could find the cars battery flat for disembarkation time.

 

[colinbal4]

Good shout Clive, thank you.

If the ignition is off though, wouldn't it cut power to the 12S socket?

I have a Mercedes GLE with a car specific wiring kit.

I'll test it with a multimeter and if its permanently live, I'll stick in one of these electronic switches which opens the switch if it detects voltage dropping below 12.5v. I want to rewire my towbar hookup as 13pin anyway.

 

[DaveA1]

My fridge does cool off battery, it's been on the last 2 1/2 hours since my post earlier, having not been switched on for weeks, and the freezer compartment is ice cold, whereas it was at room temperature 2 1/2 hours ago. Cant really feel any heat kicking out the vent outside like you do when it's on 240v, but it is quite a warm day so I might just be unable to feel the difference on the back of my hand.

240v hookup disconnected, 12N and 12S plugs disconnected, master 12v switch on, switch on front of fridge set to the battery.

Maybe it would drain the battery very quickly, I have a Numax 105ah class B, but it definitely does work.

Not that it will ever run off the battery except perhaps when parked up at motorway services with car engine off.

It's an Electrloux Dometic with a front switch like this

Is that not set on the 230v setting???

 

[Craigyoung]

That's what I thought before ; thats set to electric hook-up not battery

 

[colinbal4]

I'm not that daft chaps, that picture was taken months ago, this morning it was set to battery and there was no 240v supply to the van

 

[otherclive]

Good shout Clive, thank you.

If the ignition is off though, wouldn't it cut power to the 12S socket?

I have a Mercedes GLE with a car specific wiring kit.

I'll test it with a multimeter and if its permanently live, I'll stick in one of these electronic switches which opens the switch if it detects voltage dropping below 12.5v. I want to rewire my towbar hookup as 13pin anyway.

On reading your post I misread it as working from car battery as well. The car should be isolated when the ignition is off.