Shore Power Arctic Cable: 1.5mm or 2.5mm?

nigelmercier

nigelmercier

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I'm considering replacing four 10m - 15m power leads with a single 40m lead, plus a 10m lead for everyday use.

I know 1.5mm is adequate for 16A, but not when rolled on a drum. So 2.5mm is the better option, but at a cost. The price at my local wholesalers TLC is £100 for 100m, but I only need 50m.

So two questions:

[1] Would you go for the 2.5mm?
[2] Would anybody be interested in buying some of the excess at cost?
 
1.5 mm really is the abslolute minimum for 16a and fully wounnd on a drum 40m would drop to around 4a!! there are also losses in the cable that obviously increase with length. having said that one continuous cable is much preferable to four sets of plugs and couplers. you need to know your maximum demand, are you really using anywhere near 16 amps? if you are using more than 10 amps for more than 5 minutes at a time then you should really be going for the 2.5 at 40 metres.
 
2.5 amp was my chose because I see 1.5 as lighting grade but that's just me maybe. I would also not leave any of it on the drum when in use. It makes a good heating element.
 
The design rule in the IEE regs[1] is that the maximum allowable voltage drop [due to the cable] is 2.5% of the system voltage. i.e. 6V for 240V supply. Note that this isn't just because of the load you're drawing, but because the current carrying conductors need to be able to carry enough current under fault conditions to make sure that the fuse / breaker blows before they overheat, and also because of the size of the earth wire. (To really do it properly, you should calculate the earth loop impedance, too.)

2 core cable on AC usage drops:

29mV/A/m at 1.5mm^2
18mV/A/m at 2.5mm^2
11mV/A/m at 4mm^2
7.3mV/A/m at 6mm^2

At 16 amps, a 1.5mm^2 cable is OK to ~13 metres, and 2.5mm^2 to ~21 metres

You would need to go to 6mm^2 for 16 amps at 40 metres - this assumes that the marina breaker is 16A. If it is smaller or bigger, you should use that figure when calculating.

Having said all that, I've got 20m of 1.5mm^2 plugged into another 15m of 1.5mm^2 just to reach a free power point. I only use it occasionally for the battery charger, phone chargers, etc, so the loading's not a problem, but it really should be on a 5A breaker (and Conwy marina should provide a few more power points ! /forums/images/graemlins/mad.gif)

I'm not an electrician, so would be happy to be corrected on the above.

[1] I'm not sure this part of the regs actually applies to this situation, but it is still useful as a design rule. More info here

Andy
 
I was under the impression that at least some of the heat build-up was due to induction from coils, on a drum for instance. This would be the same for 1.5mm and 2.5mm. I would always unroll a drum if using anything more than the smallest load.
Allan
 
iee wiring regulations do refer to structural wiring only and volt drop calculations have changed as of july this year but i wont bore you with details. flexible leads have different figures or you wouldnt be able to buy one of these with a 13a cartridge fuse. link this also looks like a compartively cheap way to buy 50 m of 1.5 arctic flex. however i would still say go for 2.5 for your requirements
 
Any idea of what the figures are for flexes? (I've no idea what the 17th edition contains /forums/images/graemlins/confused.gif)

Andy
 
Thanks Dave - actually, I had read it a while ago, and marvelled at the apparent requirement for an isolation transformer in all cases, but that's a whole different thread /forums/images/graemlins/smile.gif

There's nothing on flexible cables (cords?) in it though. It's not a burning issue (no pun intended!) but I'm curious to know what the requirements are.

Andy
 
Isolation transformers /forums/images/graemlins/blush.gif oh please don't start on that one /forums/images/graemlins/grin.gif

What exactly are you after Andy ?
Are you after voltage drop on flex ? current ? heat ? or what ?
Got quite a lot of info here, and links to other sites, but I don't think you'd appreciate having to check them all /forums/images/graemlins/grin.gif
 
[ QUOTE ]
What exactly are you after Andy ?

[/ QUOTE ]

I'm curious to know whether there is a similar requirement to the 5% volt drop for shore power leads, etc. and if so, what it is. Only I don't want to know it badly enough to have to bother reading through loads of regulations /forums/images/graemlins/smile.gif (I used to have access to the 16th edition 'on site guide'(?), and a bloke who knew about these things, but time moves on....)

Andy
 
halfords were selling 25m of 2.5mm cable with connectors for £30 recently advertised for caravan hook up. orange coloured and I assume arctic.
 
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