# what size rcd consumer unit "vw type 25?"



## 103302 (Mar 7, 2007)

i'm am in the process of fitting a 240v system in my camper van, but what size rcd do i need?? would a 25a rcd be sutible for running a fridge and a hairdryer at the same time??

and if so where can i get a good deal on one??


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## 101600 (Oct 30, 2006)

20-25amp is good enough no idea where to get a good deal depends if you want to mount it then box it off yourself. if so DIN rail mounted breakers would be good or maybe a premade housing if you are not making it yourself.


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## philjohn (May 29, 2005)

Hi,

Have a look here, reliable company I have used recently for the same thing http://www.olearymotorhomes.co.uk/

Phil J


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## gaspode (May 9, 2005)

Hi schmidy

Welcome to MHF

If you think about it, the maximum current you'll be able to draw from a hook-up is 16 amps and more usually 10 amps. Therefore anything rated at greater than 16 amps is overkill. As suggested a 25 amp or 30 amp would probably be appropriate as you may have problems getting a smaller one. Choose one with at least two breaker capacity and 30ma RCD trip current. One designed and sold for use in domestic garages would probably be best if you can't get one specifically for motorhomes/caravans. I'm sure I've seen ones in the Ebay caravan section, otherwise go to any electrical trade factor and ask their advice, they'll usually give you a good discount.


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## maddie (Jan 4, 2006)

Hi try screwfix they are not bad prices 
terry


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## shortcircuit (Mar 19, 2006)

For your information the size of the mcb required does not relate to the load it is supplying but to the size of cable it is connected to which supplies the load. The cable has to be sized to the load

To simplify this, a 1mm flex has a current carrying capacity of 10A therefor should not be connected to a 16A mcb. To cover your proposed loads use 1.5mm flex which has a current capacity of 16A.

As suggested use the garage type consumer unit. This has a main switch with a 30mA RCD, a 6A mcb for your lighting circuits and a 16A for your power using circuits.

Get some advise from an electricians and definitely get it tested by a competent person before it is power up


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## sallytrafic (Jan 17, 2006)

shortcircuit said:


> For your information the size of the mcb required does not relate to the load it is supplying but to the size of cable it is connected to which supplies the load. The cable has to be sized to the load
> 
> To simplify this, a 1mm flex has a current carrying capacity of 10A therefor should not be connected to a 16A mcb. To cover your proposed loads use 1.5mm flex which has a current capacity of 16A.
> 
> ...


Don't rely on PVC/PVC 1.5mm cable carrying 16A it depends on how it is mounted for example bunched with other cables and buried in rockwool insulation where any heat generated can't leave, it would be a lot less than 16A. The tables at the back of BS7671 give the derating for cable types dependant on instalation and bunching.

Regards Frank


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## shortcircuit (Mar 19, 2006)

Thanks for the input and I have no intention of going into a technical debate.

schmidy

"Get some advise from an electrician and definitely get it tested by a competent person before it is power up"


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## 101600 (Oct 30, 2006)

I always run everything other than lights in 2.5mm on things like this. 

Are you wiring it yourself? and as said if you are not a spark get one to check it if you do it yourself!!!!


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## 103302 (Mar 7, 2007)

roboughton said:


> I always run everything other than lights in 2.5mm on things like this.
> 
> Are you wiring it yourself? and as said if you are not a spark get one to check it if you do it yourself!!!!


will be running cables myself but will get it wired in by an electrician.

first time using "mhf" and i'm well inpressed with all the help i'm getting.

thanx
paul radnedge.
lfc to make it 6!


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## safariboy (May 1, 2005)

My understanding is that the cable should be multi-stranded in a motorhome and not the single strand used in a house. But if that is wrong I am sure someone will tell us.


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## sallytrafic (Jan 17, 2006)

safariboy said:


> My understanding is that the cable should be multi-stranded in a motorhome and not the single strand used in a house. But if that is wrong I am sure someone will tell us.


You are correct Safariboy - its in the wiring regs BS7671

regards Frank


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