Power cable types suitable for Boat marina

I would tend to refer to what it states within the BS7671 latest edition, if struggling to interpret this you could always go to a supplier to assist. I would go to R&M electrical wholesalers they serve multiple industries.

plain XLPE/PVC “land” power cables are usually not the right choice on a floating pontoon. They can be used only if they’re specifically rated for wet locations, UV/sunlight, and mechanically protected—otherwise PVC jackets embrittle, crack, and don’t like constant flexing. Marina rules also call for different cable constructions in areas that move or can be flooded

Presuming you mean the "fixed" installation cables, rather than the "shore cable" connecting the socket to a vessel.

BS 7671 section 709 lists thermoplastic and elastomeric insulation/sheath as being acceptable (with conditions) - I think XLPE is usually classed as thermosetting rather than thermoplastic though - I wonder if the intention was to exclude XLPE from that clause (it seems odd, since PE generally does better than PVC in wet conditions). For non-moving structures, most cable types including PVC sheathed MI, and thermoplastic sheathed armoured cables and "underground cables" in general appear to be acceptable.

On floating pontoons, overhead, non-sheathed cables in wiring systems, aluminium conductors and MI cables are explicitly prohibited.

Otherwise it seems to be just down to general environment - the necessary flexibility of the cables crossing from from shore to pontoon may depend on local conditions - is the pontoon exposed and move with every wave, or is there just a gentle up/down twice a day with the tides? Most black sheathed cables as OK in sunlight. Water resistance again depends on the conditions - usually between AD4 (splashes) to AD6 (exposed to waves) - although none is as demanding as complete immersion.

   - Andy.

Funnily enough I've just come back from an inland boat holiday on the lakes in north Germany, Certainly there the wiring is much as it might ould be at a small festival or perhaps a 230v wired building site in the UK, although either the local regs are not as tight as the UK ones about not sharing RCDs or there are a lot of not quite compliant installations. The hook-up cables to the boats are usually little more than a 3 core version of the orange PVC sort of thing you might see  in a UK caravan park or supplying garden equipment. Only the very exxpensive looking ones have the black rubber covered stuff. 

This is almost exclusively 16A single phase stuff, much like UK caravans, although a few of the seagoing boats seem to also be able to take 32A 3 phase, though only the larger marinas offered it.

Our boat at least had a volt meter, and a reverse polarity and voltage out of spec lock-out, as well as a true double pole RCD suggesting a degree of German mistrust of the shore power  - though it never operated, and my own additional polarity and earth checking (busman's holiday?) never found any faults

The fixed wiring, at least that which you can see from the RCD box to the sockets is either more of the rubber flex or thin NYY-J - the 3 phase version of which seems to be the almost universal choice for the wiring from the shore into the pillars, where applicable in flexi-duct and secured on the dry-ish underside of pontoons and so on.

I must admit on first sight I did wonder a bit, as it has a rough life, but in practice it all works, and in the rare event of a live end socket falling into the water the RCDs seem to do what they should quite admirably. (the instructions and training is always to connect the boat end first, and then to jump ashore with the plug, though occasionally you see that folk make mistakes and things do happen !)

not perhaps an answer to the exam question, but an anecdote that it certainly can be done.

Mike.

mapj1 said:

Funnily enough I've just come back from an inland boat holiday on the lakes in north Germany

I wondered where you had been. :-)

Well, I have been on the beautiful Shannon/Erne waterway for 2 weeks and no *** missed me!!! Can’t blame them really! Wish Waterways Ireland had provided a tad more electrical connections! 

and that photo is load diversity in action. I've always been amazed how many of those 'ray gun' shaped adapters can be cascaded before things actually trip.

I hope you too had an enjoyable holiday, and didn't (as I did, sadly) come home with more photos of substations, pylons etc as of the boat, the family, interesting places visited etc.

Did your boat have an RCD and shunt trip connected to an over and under voltage monitor as well ?

Mike

mapj1 said:

I hope you too had an enjoyable holiday, and didn't (as I did, sady) come home with more photos of substations, pylons etc as of the boat, the family, interesting places visited etc.

Sad indeed! I can’t imagine anyone doing that! Still, here is a nice photo I took of some hay bales.  Shannonbridge Power Station in the background is totally incidental, although, interestingly, it has recently been converted for use as a temporary emergency generation unit. Those stacks are exhausts for the diesel-powered turbines.