Steveflet Posted July 18, 2018 Report Share Posted July 18, 2018 Hi folks, I have read lots about galvanic isolators etc on here. My boat has no 230 volt equip on board just 12 volts and I am wondering if I run a shoreline in to the boat with a couple rcd protected sockets on the end and use just plug in equipment would I need an isolator? Many thanks in advance Link to comment Share on other sites More sharing options...
Tony Brooks Posted July 18, 2018 Report Share Posted July 18, 2018 In my view no. I do it as and when I need to. The problem comes from joining your hull to the the mains earth (Green & yellow) cable. You will not do that witha simple extension lead that does not connect to any permanent wiring. Link to comment Share on other sites More sharing options...
Steveflet Posted July 18, 2018 Author Report Share Posted July 18, 2018 Thanks for that it makes sense, however taking it a step further if I were to power a smart charger to my batteries via the same means would this still be safe from the point of view of corrosion? Link to comment Share on other sites More sharing options...
Tony Brooks Posted July 18, 2018 Report Share Posted July 18, 2018 15 minutes ago, Steveflet said: Thanks for that it makes sense, however taking it a step further if I were to power a smart charger to my batteries via the same means would this still be safe from the point of view of corrosion? I suspect that rather depends upon the internal charger wiring. If the mains earth cable (but most such chargers seem to be double insulated) connects to battery negative then there may be a problem but if not it should be safe from the hull corrosion point of view. Unless you were leaving the charger connected for long periods then I doubt any corrosion problem would be detectable. Different if you left it on charge for weeks but in that case the boat should be properly wired. Link to comment Share on other sites More sharing options...
Chewbacka Posted July 18, 2018 Report Share Posted July 18, 2018 An extension lead on an occasional basis whilst not being best practice is not uncommon. But if a semi-permanent arrangement it should be done correctly as a fault to earth on the boat could make the hull live and would give a severe or possibly fatal electric shock to someone touching the hull from the bank. That said the rcd trip on the bank side supply should protect and prevent that......... Link to comment Share on other sites More sharing options...
Steveflet Posted July 19, 2018 Author Report Share Posted July 19, 2018 Thanks for your advice and helpful comments guys it's much appreciated. Thinking of going down permanent supply route, are there any particular make of isolators you would recommend to help safeguard against corrosion? Link to comment Share on other sites More sharing options...
Sea Dog Posted July 19, 2018 Report Share Posted July 19, 2018 16 minutes ago, Steveflet said: Thanks for your advice and helpful comments guys it's much appreciated. Thinking of going down permanent supply route, are there any particular make of isolators you would recommend to help safeguard against corrosion? I'm glad you chose that route Steve, it's by far the safest and might even add value to your boat. Link to comment Share on other sites More sharing options...
Jen-in-Wellies Posted July 19, 2018 Report Share Posted July 19, 2018 The big name manufacturers will be good. Victron, Mastervolt, Safeshore. Go for one with warning LED's that show faults and allow easy testing. As usual, no name cheapo Ebay stuff is a bad idea for electrical equipment! You will also want to fit a consumer unit with an RCD and breaker(s). A small one designed for garages is ideal, though the breaker(s) may need swapping for ones with more appropriate trip currents. Jen Link to comment Share on other sites More sharing options...
Steveflet Posted July 19, 2018 Author Report Share Posted July 19, 2018 Thanks again all, will be getting artic blue 2.5 cable for internal wiring from rcd to sockets. Is it acceptable to run cable in centre lighting void with 12 volt lighting? as running trunking under the gunnels would mean going through the bathroom and am not to sure about that? Link to comment Share on other sites More sharing options...
Sea Dog Posted July 19, 2018 Report Share Posted July 19, 2018 Depending on what you intend to fit, you may find 1.5mm cable is adequate for your needs as I expect you'll be going for a 16 amp breaker aboard and you'll find most shore supplies are 16 amp max rated. Have a look at the guidance in the Recreational Craft Directive (RCD). You don't have to abide by the RCD requirements, but it will give you a good idea of best practice. Someone will have a link for you shortly, otherwise Google will find it for you - it's available on the Web. Link to comment Share on other sites More sharing options...
rjasmith Posted July 20, 2018 Report Share Posted July 20, 2018 19 hours ago, Sea Dog said: Depending on what you intend to fit, you may find 1.5mm cable is adequate for your needs as I expect you'll be going for a 16 amp breaker aboard and you'll find most shore supplies are 16 amp max rated. Have a look at the guidance in the Recreational Craft Directive (RCD). You don't have to abide by the RCD requirements, but it will give you a good idea of best practice. Someone will have a link for you shortly, otherwise Google will find it for you - it's available on the Web. Best way to read Recreational Craft Directive related info is to use Manchester City Library's (MCL) free link to British Standards Online (BSOL) website (link here). Click on the "Go to British Standards Online" box. Once in BSOL, in their little search box (top right hand, in the grey bit) type in the number "13297" for the ISO standard that covers the RCD requirements for Boat AC electrical systems. A list of 5 results will come up. You want the top one which will give you the latest edition (2014) of BS EN ISO 13297. To read the document (you're not allowed to print or download it I'm afraid unless you want to buy it for £198!), click on the little icon to the far right of the title (looks like a little Adobe Acrobat logo, above the words "In your subscription"). After a short delay a read only .pdf version of the doc will open and you'll be able to read all of it for free (all paid for by MCL). Very few libraries in UK cover the cost of doing this now - thank you MCL! You can read copies of 13297 and some other RCD ISOs by just Googling but these are very often pirated copies of out of date issues. The 2014 issue of 13297 has very nice drawings of typical boat AC installations at the back, earlier issues don't have these. Richard Link to comment Share on other sites More sharing options...
Steveflet Posted July 20, 2018 Author Report Share Posted July 20, 2018 Thanks again for the all time and effort put into these replies. I'm sure I will have many more questions going forward! Steve Link to comment Share on other sites More sharing options...
Buckely Posted July 23, 2018 Report Share Posted July 23, 2018 Take into account how the cable will be routed when selecting the cable size. The IEE regs BS7671 require the cable capacity to be derated by (from memory), 50 % if 500mm or more pass through insulation. I know BS7671 doesn't apply to boats, but a fire ( or 'potential' thermal event as the legal department of a previous employer insisted we call them) is a fire! Link to comment Share on other sites More sharing options...
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