Hook up cable - what rating needed?

lewisnoble · Feb 23, 2013

I hope some of the electrical techies can help here . . . .

The hook up cable I use was purchased from an outdoor camping shop, big heavy duty cable, stiff and difficult to coil up into small space. Bearing in mind that the actual load is very low (power used for topping up batteries, even when the heater is on the electricity does not provide the heat, just the pump and blower) - is such a heavy duty cable necessary?? Is there any reason why a cable with rating of say up to 8 amps would not be OK??

Much easier to coil and store in boot . . . .

Someone has mentioned something about voltage drop - is that liekly to be a problem??

Any advice, please?? Thanks

Lewis

Andresz · Feb 23, 2013

Hello
As you say, the electricity does not heat, only supplies the electronic control and fuel pumping. Than, the highest current flow would be to charge the batteries; about 25 amps with 12 wolts, plus lets say 10 amps maximum, for other apliances (light, fuel pump, water pump, fridge which is 4.5 amps, etc) 35 amps alltogether with 12 volts, = 420W. With ommission of the circuit losses it ends with about 2 amps in worst case scenario. Then you may connect additional devices to the 230v socket, which you need to take into account, in this case electric heater 1000W = 5 amps, cofee maker 300 watts = 1.5 amps.
So, the car itself should be no more than 2 ampers (perhaps 3-4 with circuit loses) on maximum case scenario, but than you have to remember about the 230V socket inside, do you use it or not, and what for.
I personally use a spinning 8 amps cable, quite small when colled, no problems with it whatsoever.

Regards
Andrzej

lewisnoble · Feb 23, 2013

Thanks Andresz - yes, that's what I thought. And as you say, you have to make sure that no-one else puts an unexpected load (eg. electric fan heater or radiator or similar) onto the 240v socket.

But as our socket is used only for charging, dvd player, exterior light etc, and we are the only users of the van, I think this is OK. 8 amp cable is what I had in mind.

Lewis

SteveW · Feb 23, 2013

Hi

Totally agree with you on the amount of load the Cali will pull but you need to remember that the hook up supply on uk campsites is protected by a 16amp mbc or rcbo. With this in mind should you have a fault on the load/Cali then the breaker won't trip until its pulling in excess of 16 amps ( providing you don't have an earth fault). In these conditions the a 8amp hook up cable will at best get pretty warm and at worst set on fire :shocked

Not a good thing if your asleep in your Cali.

Personally I would not risk using any hook up cable with a lower rating than 16-20 amps.

Only other option I see its to put a 6-8 amp fuse or breaker at the supply end of you hookup lead.

Yes you do have a trip in the Cali itself to but these can themselves fail.

Cheers

Steve.

Andresz · Feb 23, 2013

SteveW said:
Hi

Totally agree with you on the amount of load the Cali will pull but you need to remember that the hook up supply on uk campsites is protected by a 16amp mbc or rcbo. With this in mind should you have a fault on the load/Cali then the breaker won't trip until its pulling in excess of 16 amps ( providing you don't have an earth fault). In these conditions the a 8amp hook up cable will at best get pretty warm and at worst set on fire Not a good thing if your asleep in your Cali.

Personally I would not risk using any hook up cable with a lower rating than 16-20 amps.

Only other option I see its to put a 6-8 amp fuse or breaker at the supply end of you hookup lead.

Yes you do have a trip in the Cali itself to but these can themselves fail.

Cheers

Steve.

Steve
I would not worry about the fuse failing to break the circuit, in case of sudden high power demand. The 8 amps rating on the cable is a continous max current for the cable. It will allow much higher currents in short term. And a cause to brake the fuse is typically a short term failure, like a shortcut on a device. Of course the low rate cable must not be long, several meters maximum.

It is like at home, where you may have 16 amps fuse blown easly by a device which is nominally 1 or 2 amps, in an internal shortcut scenario. Or a 16 amps fuse in a Cali, blown by a 20 wats lamp socket of internal light (somebody was giving the example in another topic).

But you are right, if you want to be 100% in line with the safety regulations it should be more than 16 amps cable.

Regards
Andrzej

lewisnoble · Feb 25, 2013

Thanks again. Thinking about it, I am sticking with the 'heavy duty' cable, but will look around for more flexible cable material. Yes, we ought to be OK with lighter duty cable, but that means lots of instructions / warnings etc if we lend the cable to others going camping.

Thanks for advice.

Lewis