Correct wire for marine 240v?

[grumpy_o_g]

can you manage to install as a ring main.
i have a "Garage" type Consumer unit with2 mcb`s

Personal opinion but I would tend to avoid a ring main on a smaller boat as you are more likely to lose the lot from a single fault - it'll certainly be harder to find if you do get a fault somewhere in the ring. That and you need to run heavier cable - ring main is better in every other way though.

If you're talking about an MCB as in current trip or fuse then you ideally need one for each outlet rated for that outlet. Having said that you will be over-rating the trip on the ring main compared to the max capacity for each outlet so it's not the end of the world. The fuse on each plug should protect you in theory.

If you can get tinned at a sensible price go for it, if not just use standard multi-strand.

If you're re-wiring spend a long, long time thinking about where you're running the cables and where positioning outlets and fuses, breakers and trips. You'll be very glad in a few years when you either add something or try and find a problem or whatever. Try and stay away from the VHF as well for good measure.

 

[Stemar]

I'm inclined to agree that individual circuits for each socket have advantages on a boat, but it may be a lot easier to run a ring main.

Consider also, that sockets are cheap and easy to install when you're starting from scratch and a lot harder to do later, so be generous with them - except near the sink and in the shower!

 

[late-night-lochin]

When I rewire the 6 sockets, is it best to bring each one back to it's own MCB in the new consumer unit or to a junction box and into one MCB in a smaller consumer unit? Maximum simultaneous load is 25 amps 220v

Hi Black Kipper

Have you actually got a 32A shorepower supply? Most are 16A.

There has been a debate about ring mains veses radial circuits on another thread.

I have installed a ring main on my boat, I used 2.5mm arctic flex with a blue outer sheath. (Arctic flex is also available with a yellow outer sheath but yellow indicates 110v and this is normally used for building site tools.)

A 2.5mm ring main would be fine for a 32A circuit anyway.

Tinned cable is obviously far more corrosion resistant and I use it for 12v wiring where the terminations are either external or below the cockpit. Unfortunately, tinned cable / flex is expensive so I don't bother with it inside the accommodation. I have still got some old existing and also removed plenty of old untinned wiring from inside my boat and have only ever found problems where it has been subject to moisture. I.e. below decks and where terminations had been made in lower quality enclosures.

One problem with domestic 240V sockets, switches etc is that their terminations are really intended for solid core cables - not flex. You can overcome this problem by fitting "bootlace ferrules" to the termination ends of the wiring.

You can buy the bootlace ferrules and the appropriate crimping tool from such places as RS Components and Furneaux Riddall in Portsmouth.

 

[VicS]

same document.. different place..

ISO_13297 seems to be available here ->

http://earlhill.de/files/ISO_13297_...Systems_Alternating_current_installations.pdf

Thanks.

Also now bookmarked

 

[PCUK]

27 years with domestic copper cable and never a problem - But then my boat doesn't vibrate!

 

[Bru]

I have installed a ring main on my boat, I used 2.5mm arctic flex with a blue outer sheath. (Arctic flex is also available with a yellow outer sheath but yellow indicates 110v and this is normally used for building site tools.).

I'd not use Arctic on a new installation. We're moving over to HO7 for marquee work 'cos Arctic is only British Standards compliant at 110v in "outdoor" environments (which includes marquees) although we've been using blue arctic perfectly safely for years

HO7 is only a little more expensive and is BS compliant for 240v outdoors and therefore better able to withstand a damp environment ... which boats tend to be of course!

Equally, I wouldn't rush to strip out arctic cable (we've got miles of the stuff and damned if we're going to throw it all in the bin just like that)