16A or 30A shore power cable

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fjweaver

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The maximum load on our marina on each outlet is 16 Amps.
I'm not sure whether to buy a 16a power lead or go for the 30a one. I will be installing a 30a Marinco inlet.
I guess the 16a is fine but was wondering about ,say, Cherbourg?
 
Why not work out your max needs with everything on... 30A is a shade over 7kW at 240V.
Don't think I have ever come across a marina supply that big FWIW.
 
There are boats double the size of yours using 16 amp supply. Out in Turkey it is only boats with Aircon that use anything bigger, and most of them are 50 foot plus, or motorboats with a lot of domestic electrics on board.
 
We have just upgraded from 16 amp to 32 amp. In marinas we use the electric kettle, toaster, water heater and in winter a 2 Kw fan heater if the battery chargers happen to kick in on top then we exceed the 16 amp. It is unlikely that all will be on at once but if the wife gets up has a shower then decides to put the toaster and kettle on during the winter "puff".
 
The answer for minor pedants is that you need to take voltage drop as well as current capacity into consideration.

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.

2 core cable on AC usage drops 29mV/A/m at 1.5mm^2, or 18mV/A/m at 2.5mm^2.

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

At 30 amps, a 2.5mm^2 cable is OK to ~11 metres.

In practice, most things work - you're highly unlikely to draw anything like 16A on a small-medium sized yacht unless you've got the fan heater and the kettle on at the same time[2].

I've got 20m of 1.5mm^2 plugged into another 15m of 1.5mm^2 just to reach a free power point in Conwy (marina!), but then I only use it for the battery charger, phone chargers, etc.

[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.

[2] Edit: This was before I saw 'Mocruising's list above /forums/images/graemlins/shocked.gif.

Andy
 
If you're going to (for instance) the Med, I would advise the heaviest cable you can handle/store and a handful of adapters. If you make up a 32amp set with a 16amp shore plug, it will meet most of your needs, and if you end up in somewhere with only 180 of the 220 volts at the pontoon, you will not lose any more in YOUR cable. you can make up a 16amp socket with a short cable to any other type of plug -32amp, french, spanish, 13A, etc. to suit every occasion.
We also had a tail with a 16a socket on it permanently wired to our shore end, that way we could share an outlet if they were scarce.
 
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