Shore Power Consumer Unit

rosta

rosta

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The shore power consumer unit that was fitted to my boat is a standard domestic MK unit and it's located under the instrument panel. It works but its showing signs of rust and frankly I don't trust it, I'm not sure how it would behave if it got damp. So I am replacing it with a garage unit, with RCDs and a couple of MCds which should be more robust and weatherproof.

At the same time should I'd like to re-locate the consumer unit into the engine space where the immersion heater and battery charger are? Is there any disadvantage to putting it there (accessibility, fire risk, heat etc)? Where are consumer units usually located?
 
wait for the experts to respond but before you buy you should ensure the circuit breakers are dual pole for marine use.

I wouldnt want to be crawling into my engine bay to re trip a breaker and awkward to reach breakers preclude leaving women and children alone on board.
 
So I am replacing it with a garage unit, with RCDs and a couple of MCds which should be more robust and weatherproof
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. It would be wise to get a waterproof one. To which end Screwfix do an MK one for about £40 which conforms to IP65 with a 2 pole RCD and two mcbs (1x 16 amps and 1x 6amps)

You should read ISO 13297 and also take note of the requirements, even if not strictly applicable to you and your boat, of the relevant parts of Chapter 3 of the Boat safety scheme

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

http://www.boatsafetyscheme.com/downloads/BSS_Guide_chap3.pdf
 
Thanks all for the advice.

Is there any problem re-locating the consumer unit into the engine space? I've plenty of room there and it would be easy to get at. My concern is the effect of heat and potential fire risk.

Regards
 
rosta said:
Thanks all for the advice.

Is there any problem re-locating the consumer unit into the engine space? I've plenty of room there and it would be easy to get at. My concern is the effect of heat and potential fire risk.

Regards
Click to expand...


Not if correctly installed and not too close to major heat sources like manifolds and away from DC cabling. There are any number of builders that do it and it does not contravene ABYC, NMEA 0400, BSI or RCD regs or recommendations. If you use the Sentry one indicated you MAY have to change one of the MCBs as it is a factory assembled unit so there is no choice of which RCD or MCB you get. As I have no idea of your boat type I'm assuming diesel as if it's petrol the answer is don't even think about using non ignition protected stuff down there. Have the circuits tested by a competent person when you have completed the installation also.
 
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In a machinery space all cables should be oil and grease resistant.
The cable's current carrying capacity should be derated.
It is a good ides to use glanding into the consumer unit IMHO.
 
The engineer said:
double pole breakers are not required for marine use unless the circuits are un polarized.
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Isnt that the point ?

When plugging your boat into shore power you really have no idea what you are plugging into.

Even if you plug in and check you cant be certain someone is not going to add their splitter later reversing polarity hence the need for a dual pole circuit breaker.

imho and backed up by BSS requirements.
 
Point taken. My comment was with regard to the ISO standard requiremnts. I was not aware that BSS stipulates double pole MCB. Would you mind pointing me in the direction of where that is stated please? I am not disputing it but genuinely interested:)
 
The engineer said:
Point taken. My comment was with regard to the ISO standard requiremnts. I was not aware that BSS stipulates double pole MCB. Would you mind pointing me in the direction of where that is stated please? I am not disputing it but genuinely interested:)
Click to expand...

I hope someone jumps in here because its about 8 years since I read up on this , my books are at home and they arent very interesting to wade through.
 
No worries, I am gullty of not paying attention here. Shore supply is a double mcb requirement. It is an ISO requirement too. I have got my head on distribution circuits.
 
David2452 said:
as if it's petrol the answer is don't even think about using non ignition protected stuff down there.
Click to expand...

Thanks David. Yes, its petrol which is why I posted the forum for advice.

So it looks like the safest option would be to install the new consumer unit where the old one was sited, under the instrument panel. The problem is its a sports boat and so its a bit open to damp but hopefully an IP65 rating should prevent any future problems.

What you said also raises another issue. The existing shore power wiring leads through the engine space to two standard domestic sockets, the HW immersion heater is plugged into one and the battery charger into the other. Is this a safe setup? Would a safer option be to rewire the immersion and battery charger so that they were both switched from the saloon?
 
"Would a safer option be to rewire the immersion and battery charger so that they were both switched from the saloon? "

Absolutely yes, also is the charger ignition protected?
 
Also take on board the other good advice given, you will need a consumer unit with double pole MCBs or an empty one with four positions to accomodate the two wider MCBs.
 
David2452 said:
Also take on board the other good advice given, you will need a consumer unit with double pole MCBs or an empty one with four positions to accomodate the two wider MCBs.
Click to expand...

Sorry David, another supplementary question. Is there any disadvantage in going for Double Pole RCBOs which I understand combine the functions of an RCD and MCB?

Regards
 
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