# Consumer unit and charging



## chrissailor (Jul 24, 2008)

I'm planning the conversion of a Vauxhall Vivaro. I'll be providing for a mains hook up via the conventional connector and consumer unit. Due to the small size of the van and the cost of a fridge I've decided to get by with a 12v coolbox. Lights will be LED so will have low power requirements and I'll have a 12v submersible pump for the water. I plan to fit a smart charger (Ctec or Sterling) to keep the leisure battery topped up when the mains hook up is connected and will run the 12v items from the leisure battery. My plan was to wire the charger to one of the outputs from the consumer unit, leaving the other output to connect to a socket to use for a kettle or small fan heater. But... (why is there always a but?). The consumer unit has a 10amp and a 5 amp output. The charger will need the 10amp one. so the 5 amp one won't run anything worthwhile. Or have I got that fundamentally wrong somewhere. Are all consumer units rated at only 15amps ie with 10amp and 5amp outputs?


----------



## rayc (Jun 3, 2008)

The rating of the main switch is not the sum of the individual MCB's [fuses].
In my house the main switch / RCD is 63A. The cooker MCB is 45A and the shower 32A as is the ring main. The assumption is that you will not have all circuits loaded at to maximum at the same time i.e the ring main will be 32A and may have 10 + 13A sockets fitted. Obviously the expectation is that you will not be drawing 13A through all the sockets at the same time. What is the rating of the main switch/ RCD in your consumer unit? I would think it is possible to change the 5A MCB for a 2nd 10A one without any problems.


----------



## chrissailor (Jul 24, 2008)

Rayc

Thanks for that. The consumer unit is a Plugin Systems one that I bought from a caravan dealers so will be a fairly standard item I assume. The RCD appears to be rated at 40amp, while the MCBs are 10amp and 5 amp respectively. Even if I wire the charger through the 10amp output and reserve the 5amp one for a 13amp socket, wouldn't that trip the 5amp MCB if I say plugged a kettle into it, regardless of what the 10amp output was drawing? 

Chris


----------



## rayc (Jun 3, 2008)

chrissailor said:


> Rayc
> 
> Thanks for that. The consumer unit is a Plugin Systems one that I bought from a caravan dealers so will be a fairly standard item I assume. The RCD appears to be rated at 40amp, while the MCBs are 10amp and 5 amp respectively. Even if I wire the charger through the 10amp output and reserve the 5amp one for a 13amp socket, wouldn't that trip the 5amp MCB if I say plugged a kettle into it, regardless of what the 10amp output was drawing?
> 
> Chris


Chris, one thing at a time. The Consumer unit will be rated at least up to the RCD [40A] so you could easily replace the MCB's with higher current ones if needed.

1. Use the 10A MCB for the charger _[ don't know the rating of the charger but you say it draws somewhere between between 5Aand 10A]_. *Are you sure of this and could it not be fed from the 5A MCB?*

The link below shows a CTEK 12V 7A charger that will only be drawing milliamps from the mains.
http://www.campervanstuff.com/shop_stuff/index.php?mod=product&id_prd=975

2. Replace the 5A one with a 2nd 10A one and use it for the sockets. Ensure that the correct 3A / 5A or 13A fuses are installed in the plugs of the individual appliances dependant upon the rating of the appliance. Note that you should not use an appliance rated above 2KW,
Use low wattage kettles etc specifically designed for caravans.

Finally be aware of the current capacity site supply you are connecting too. In the UK is most likely 10A or 16A but abroad could be considerably less.

Ray


----------



## chrissailor (Jul 24, 2008)

Ray

Thanks for your time responding on this. I'm most grateful. The CTEK charger you've referred to is very much the type of thing I was thinking of installing. I'd assumed that if it's a 7amp charger it would draw 7amps. You can tell I'm naive (to say the least) on amp, watts and what they add up to! If as you say a CTEK 7amp charger only draws milliamps from the mains then in fact it sounds as if there's no problem about wiring that through the 5 amp output from the consumer unit and then using the 10amp for the socket. I can then use still my low wattage kettle or whatever without overloading the site supply and tripping their circuit breaker (never a popular action, I'm sure). The 12v items in the van (pump, lights or coolbox) can then continue to draw their power from the leisure battery, which will be kept topped up by the charger. Does that sound a sensible option or would I do better as you suggest and still wire the charger to the 10amp output?

Chris


----------



## rayc (Jun 3, 2008)

Chris, 
"Does that sound a sensible option or would I do better as you suggest and still wire the charger to the 10amp output?"

The charger linked to is rated at 120w so with mains 240v it draws approx 500ma or half an amp. 

Do what you have suggested. The sockets to the 10A and the charger to the 5A. The 5A would leave spare capacity if you wanted a mains powered water heater e.g. Carver Cascade etc.

I suggest you check the rating of the coolbox and just confirm that the charger will keep up with it. If you are not on EHU you will need to work out how long your battery will last with the cool box on 24/7.

Ray

PS, I hope that when you have got your camper on the road you pay your £10 and subscribe to the forum. Good Luck with your conversion.


----------



## chrissailor (Jul 24, 2008)

Ray

Again, many thanks for helping me to get this clear in my mind. I've not sourced a suitable coolbox yet but will give careful scrutiny to the ratings of the ones on offer. Now that you've helped to solve the electrics planning I can move forward to the next problem. I don't know what it is yet but there'll be one! And then another and another, I expect. That's one of the "joys" of converting your own van. It keeps the brain cells working though.

Chris


----------



## rayc (Jun 3, 2008)

Chris, this site is a mine of information for those converting a van to a camper. Ray 
http://www.campervanconversion.co.uk/


----------

