Consumer Unit for new timber caravan build

[Waldo64]

I've built a timber caravan/shepherd's hut. (Hut on wheels). I want to be able to connect it to the mains via an everyday caravan 3 pin connector, the sort you use on a normal caravan and freely available. My question is; what type of Consumer Unit would be best inside the hut? I will be running some 12V LED ceiling lighting (very low power draw, with transformer), a couple of table lamps, say 60w each from two double 240V sockets. Maximum power draw would be a kettle and a few lights on so, say 2.5 KW absolute tops. ( I still need to check if there's a limit on what you can put through one of these caravan type 3 pin plugs, that could be my limiting factor)
Could someone describe to me what I need to buy (I'm unfamiliar with the terminology of C.U.s), a link to a suitable product would be great.
Ideally, I'd like the CU to be as small as possible, they all seem so bulky for some reason. I'd rather pay more for a good, reliable brand; safety first. Thanks.

 

[Taylortwocities]

It depends on the plug. the rating will be written on it.
Could be 16, 32, 63 amp.

here's a selection
http://www.tlc-direct.co.uk/Main_Index/Plugs_and_Sockets_Industrial_Index/MK_Commando/index.html

 

[ericmark]

Caravans often have special consumer units with extras built in like the battery charger and 12 volt blade fuses. Since caravans need double pole RCD they don't have RCBO's fitted so need less room above the MCB's as a result. So what have you already got?

The power supply/charger is a big part of the consideration. BS7671:2008 limits the voltage so following that one should not use stage chargers as when on bulk the voltage is too high but when you look at 25A chargers most are stage chargers only by buying the special for caravans do you get 25 amp without stage charging.

Not sure stage charging is bad. Depends on your lights will they take 14.8 volts if so stage charging is OK. As to pulse charge again BS7671:2008 says no more than 1.2 volt ripple I do think when BS7671:2008 bit for caravans was written they were living in cloud cook coo land as most solar panel controllers will produce that ripple.

So lets look outside the box for a minute a B16 double pole RCBO will satisfy all sockets and a B6 MCB will reduce it for lights could even use two fuse connection units one with built in RCD.

However a consumer unit is a type tested distribution box and as soon as you do anything not recommended by manufacturer it loses it's type testing so next question is who is using it. Hired out as holiday home then clearly all t's crossed and i's dotted but for own use does it really need to be a consumer unit.

I am sure others will comment on what I have said wait and read what they say then make up your mind.

 

[Waldo64]

I've had a wee look (thanks for the link). I'll be using a blue, (seems they are colour coded) 16A socket to connect to the mains.
I've maybe confused things by mentioning 12V LEDs. These lights will be powered by a domestic, purpose made transformer/power supply taking 240V. I won't be charging anything at all. I'm just using the 12V LEDs because they are physically very small, run cool, and easy to fit in a shallow ceiling void.
This hut is just for my wife and will sit in our garden, but if its a success I may build another one for my brother, who will rent it out to holidaymakers. So I want to learn how to do it right and get realistic equipment costs. (if I build a rental model I'll get a qualified spark to fit the gear and sign it off)

 

[winston1]

A so called garage CU is what you need. Contains an RCD, a 16A and 6A MCB.

 

[Waldo64]

Thanks Winston. I've seen "Garage C.U.s" in B&Q, about £30, if I recall correctly.

What I'm not sure about is the number of "gangs" (if thats the right word, I'd call them fuses) I need. If I have two sockets and say two overhead lights, then I will need two gangs? One for sockets, one for lights. Correct?

 

[ericmark]

It needs 3 or 4 spaces with a 16A RBCO plus 6A MCB then 3 spaces with a RCD and 16A MCB and 6A MCB then 4 spaces. Unlikely you will find 3 space one so 4 space either shower or garage Consumer unit.

 

[AndyPRK]

called 2 way though I think (for 2 mcb's)