Power cable types suitable for Boat marina

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.

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!