Camping extension cord recomendation 1.5mm or 2.5mm

[Stozzer]

Hi all,

I am going camping a few times this year and will be connecting into the campsite power supplies.

As i cannot trust the power in the campsites is safe i have setup this:
The setup will be used in a fully covered gazebo and the box has a lockable lid.

This box allows me to select 10A or 6A (depending on the campsite breakers). The internal connections are earthed and use 2.5mm^2 Twin and Earth (20A rated) is used throughout because it was handy and i am paranoid.

To the spur unit (13A fused) in this box i will connecting a length of Arctic cable which connects to a 30ma IP56 13A rated inline RCD which then connects to a 16A 3 pin IP44 commando plug.

I have two choices of cable length based on some online calculators i have used for a 10A current rating and voltage drop (less than 5%) over the length of the cable:

1.5mm Arctic 35m long
2.5mm Arctic 50m long

So two questions:

1) Does using 2.5mm cable reduce the speed at which the RCD activates to a level i should be concerned about(due to the increased resistivity of the cable)? I ask because i would like a longer cable than 35m but don't want to reduce the safety of the setup for the sake of an additional 15m.

2) My knowledge says the RCD unit should be connected as close to the supply as possible so that it cuts power to the entire length of the cable (which on a campsite is at risk of being damaged) Is this correct?

 

[ban-all-sheds]

As i cannot trust the power in the campsites is safe i have setup this:

What on earth are all those enclosures for?

This box allows me to select 10A or 6A (depending on the campsite breakers).

Or both at once.

Get rid of that arrangement. Why have two anyway?

The internal connections are earthed and use 2.5mm^2 Twin and Earth (20A rated) is used throughout because it was handy and i am paranoid.

Paranoid enough to worry if the site's supply is properly earthed?

Paranoid enough to regularly check that internal wiring has survived the car journey?

To the spur unit (13A fused) in this box

Why have you got that?

1) Does using 2.5mm cable reduce the speed at which the RCD activates to a level i should be concerned about(due to the increased resistivity of the cable)?

No.

And in any event, 50m of 2.5mm² has a lower resistance than 35m of 1.5mm². You really should have known that.

My knowledge says the RCD unit should be connected as close to the supply as possible so that it cuts power to the entire length of the cable (which on a campsite is at risk of being damaged) Is this correct?

It will only cut the power downstream, so the further up the cable it is the more it will protect. And the further away it is the less it will be under your "supervision".

 

[jj4091]

I can only say that you must be going to some pretty poor campsites if the supplied electrical system is not guaranteed to be safe. I know some look a bit dodgy but they have to be tested regularly & passed as safe to use. In fact there is nothing easier than pressing the RCD test button yourself. I've never stayed on a site where it has failed to trip. Not 100% guarantee it is not faulty I know, but at least you know it is mechanically sound.

 

[Stozzer]

Third enclosure is for a voltage and current monitor which is yet to arrive. The forth enclosure is a conveanient wiring point for the monitor.

Why have two..... i wanted to be able to select the breaking current depending on the campsite limitations (some are 6A and some are 10A) which will help prevent me from tripping out the campsite power when someone plugs in a high wattage device like a hairdryer. Note the lock on one of the breakers.

The spur unit is so i have a visible indication that the power is running and a switch to control it with as well as a connection point for the cable and a fuse to protect it with.

I wasn't sure on how the RCD reaction time is affected by resistivity differences and cable lengths hence my reason for asking.

 

[Taylortwocities]

I had two immediate thoughts:

1. If you are that paranoid, i am suprised that you do not have your own RCD, rather than trust the one installed on the site…..
and
2. Make sure you completely unwind that 50metres of cable. It will heat up and can melt if you keep it coiled (depending on the load, of course)

 

[Stozzer]

I do have my own RCD "30ma IP56 13A rated inline RCD" its mentioned on the 4th paragraph as i do not trust the site ones

Thanks for mentioning the unwinding. I was aware of that.

 

[Ian2008]

Why not just buy a purpose built tent hook up like this?
http://www.winfieldsoutdoors.co.uk/...supply-unit/?gclid=CLTulbvm7csCFUieGwodDY4OkQ

 

[Stozzer]

Why not just buy a purpose built tent hook up like this?
http://www.winfieldsoutdoors.co.uk/...supply-unit/?gclid=CLTulbvm7csCFUieGwodDY4OkQ

There is no fun in that for me. I love making things that have more features than a purchasable product.
I would need to replace the cable, lower the breaker values and cable in a voltage/current monitor to that for me to be happy with it. Also that arrangement they have there doesn't protect the long cable with the RCD. If a dog chews into the cable he is toast!

 

[PBC_1966]

Why have two..... i wanted to be able to select the breaking current depending on the campsite limitations (some are 6A and some are 10A) which will help prevent me from tripping out the campsite power when someone plugs in a high wattage device like a hairdryer. .

You can't guarantee that a similarly rated breaker on the site supply won't trip first anyway.

 

[Stozzer]

Why have two..... i wanted to be able to select the breaking current depending on the campsite limitations (some are 6A and some are 10A) which will help prevent me from tripping out the campsite power when someone plugs in a high wattage device like a hairdryer. .

You can't guarantee that a similarly rated breaker on the site supply won't trip first anyway.

Very true. Its my intention to run the 6A breaker, even if it is a 10A supply. The 10A is there as an option to switch to if i keep tripping the 6A which i will be able to see why from the current monitor.

 

[PBC_1966]

With all of this, I don't see a polarity check anywhere. While most British & Irish sites don't have a problem, if you venture to the Continent they're often quite unconcerned about it (in some cases because you're using a reversible plug for the hook up anyway).

 

[Stozzer]

With all of this, I don't see a polarity check anywhere. While most British & Irish sites don't have a problem, if you venture to the Continent they're often quite unconcerned about it (in some cases because you're using a reversible plug for the hook up anyway).

I didn't think of that, thanks for mentioning it.

I will be using it in France at the Le Mans race track camping so that is good to know.

I have a plug in polarity checker which i can use to check polarity on site and then reterminate if needed.

 

[bernardgreen]

Some times the appearance of the electrical supply installation in mainalnd Europe campsites makes me dubious about whether the Earth in the supply post is actually effective as an Earth, TT tents maybe ?

 

[ban-all-sheds]

Why have two..... i wanted to be able to select the breaking current depending on the campsite limitations (some are 6A and some are 10A) which will help prevent me from tripping out the campsite power when someone plugs in a high wattage device like a hairdryer.

It won't do that - do some research into discrimination.

Note the lock on one of the breakers.

I have.

Note that it requires you to use it properly, and I'm sure you have every intention and confidence about that.

But nevertheless it would allow both to be on at the same time, which is not good.

And they are pointless anyway - get rid of them.

The spur unit is so i have a visible indication that the power is running and a switch to control it with as well as a connection point for the cable and a fuse to protect it with.

Surely your monitor will tell you if you have incoming power?

You could have done it with just a switch anyway, as the fuse is pointless - do some research into discrimination.

And why would you want to switch it off and leave it plugged in to the site supply? You can switch off all your loads with the switches on the sockets.

I wasn't sure on how the RCD reaction time is affected by resistivity differences and cable lengths hence my reason for asking.

Indeed, and I accept that, but your concern was that a 50m 2.5mm² cable would be "worse" than a 35m 1.5mm² one. It's not - it has a lower resistance, which should not have come as a surprise, as the csa is 67% larger but the length is only 43% longer.

 

[ericmark]

I can see the point in having a EZ150 and an Energy meter so you can see loop impedance and volt drop and how much power you have used in case you charged for more than you are using. I can see point in your own RCD. But I have tried the idea of a MCB set to trip before the site MCB trips and it simply does not work. Theory is good but in practice MCB's are not accurate enough to work that way. The energy meter will at least mine can be set to light an alarm lamp when the selected over load is reached. It also can show how many amps are being used better to see your getting to limit that wait until something trips.

Your camping that box is far to big.