Fitting shore power advice

[VicS]

So I would like to run a 240v cable of 50 metres from a land based junction box, along a jetty and onto my boat.

I'm happy with the onboard side of things but a cable which may be "dipped" in water, concerns me.

Save me from myself!

A properly insulated and undamaged cable should cause no problems provided there are no non-waterproof junctions in it. There should be an RCD and a circuit breaker at the shore end as well as in the boat

 

[sailorman]

a plug-in rcd will be ok on inboard end

 

[l'escargot]

Best reason for not using that is that you only want shore power occasionally and would probably wind up using the thing permenantly.

I used one for several years on my last boat, never did get round to a permanent installation.

 

[David2452]

As some confusion was introduced earlier (post 15)and for the avoidance of doubt, the Screwfix garage units I have been using and recommended contain 1 off 40A 30mA Double Pole RCD, is IP65 rated, and when correctly installed comply with all current regs.

 

[lustyd]

late to the party but http://www.ybw.com/forums/archive/index.php/t-267408.html and http://yachtlivemagic.blogspot.co.uk/2011/04/adding-shore-power.html may be useful to you.

 

[lustyd]

One sentence to read and understand is: "In un-polarized systems, double-pole circuit-breakers are required..."

More details are in "ISO 13297 Second edition 2000-12-01 Small craft — Electrical systems — Alternating current installations"

"7 Overcurrent protection
7.1 General requirements
7.1.1 In unpolarized systems, double-pole circuit-breakers that open both live and neutral conductors are
required...."


"7.2 Main supply circuits
7.2.1 Double-pole circuit-breakers shall be installed in conductors to the shore-power supply circuits..."

http://www.earlhill.de/files/ISO_13...Systems_Alternating_current_installations.pdf

Clearly the Garage consumer units linked to in above are in breach of current regulations.

Or do these requirements not apply in the U.K.?

Fit UK sockets and you have a polarised system - live is ALWAYS the same pin and you can't connect in reverse. EU plugs are the problem this is trying to solve.

The DP circuit breaker doesn't need to be in the CU (it has to be close though). I ignored this on my small boat because I can unplug the cable if need be and I was happy that the CU could stop any issues that may occur in my very small installation.

 

[VicS]

As some confusion was introduced earlier (post 15)and for the avoidance of doubt, the Screwfix garage units I have been using and recommended contain 1 off 40A 30mA Double Pole RCD, is IP65 rated, and when correctly installed comply with all current regs.

But the mcbs are single pole.
DP circuit breakers would be required on an unpolarised system, however the boat's system will be polarised ... hopefully.
A possible problem arises if the boat is connected to a supply with the "polarity" reversed. In that situation if an mcb trips, or is deliberately opened, it will only disconnect what is incorrectly the neutral, leaving what should be the neutral still connected to the live side of the supply!

 

[David2452]

The critical part her is that the system is polarised, and in the UK that is the case, personally I use a simple £15 plug in tester if using unknown supplies before settling down.