Recommend me a RCD please

[Gixer]

Hello,
Now all my 12v is sorted my mind is turning to the 240v.

At the moment there is an inlet socket on the stern locker which is wired by what looks like ordinary cable directly to a twin 13amp socket.

I was going to rip the whole lot out and install one of these kits.
240V Mains Hook-Up Installation Kit For Caravans, Motorhomes & Boats
But there is no stock for a month, most of the stuff I can source but the RCD I'm not sure about. I really want to get the right one. Anyone got any recommendations?

Thanks

 

[PaulRainbow]

The 12c Planet kit is over priced anyway. You could fit one of these :British General 5-Module 3-Way Populated Garage Consumer Unit

Connect it to the shore power socket with some 2.5mm arctic cable. It has two MCBs installed, use the 6a one for your battery charger, if you have one and replace the 32a one with a 16a one to connect your sockets to. You can also use the Arctic cable from the consumer unit to the sockets.

As it's not a new build you are not required to connect the incoming shore power to the boats ground plane/bonding circuit/DC negative, but if you do decide to connect it, make sure you fit a galvanic isolator.

 

[Gixer]

Perfect, I couldn't ask for more! Thanks again Paul, I owe you a beer!

I don't have a permanent battery charger, I just move a CTEK charger from battery to battery once a week or so.
Maybe that's next, although I'm running out of room to mount stuff on my 27f boat, LOL.

 

[Channel Sailor]

A slightly alternative suggestion:-

This fuse box: "Building Supply 30mA RCD + 16 Amp + 6 Amp MCBs (tlc-direct.co.uk)". This has in the box I think is a more a more useful 16A MCB for a 1.5mm squ cored cable wired radial circuit for a few 13A socket outlets. Note this RCD is what is called a "type AC" which is fine for basic appliances such at heaters and kettles. But if you were thinking of largish switch mode chargers on banks of batteries and computers/LED TVs (liveaboard sort of thing) then a type "A RCD" would be sensible, but these are expensive. The 6A MCB could be used for a few lights on a separate circuit, with more convenient smaller sized cable. The enclosure/box is rated at IP55 (splashproof) and comes with seals for the holes where the cables entre the box, which I suggest you use properly to try to keep the salty air out of the electronics in the RCD and MCBs.

For the shore connection I would suggest 3CORE HO7RN−F 450/750V BS7919 Black sheath flex (i don't think it is available in Orange). I have not checked the detail but this cable seems to have more small strands within each core compared to some flex cables. I have not looked at the difference to Artic flex mentioned above. I do notice the usual PVC sheathed cables are affected by UV and they are very stiff to handle in the winter (possibly not rated below 0 degrees C anyway). If using a 1Kw/2Kw heater plus a kettle/single induction plate then 2.5mm CSA cores would be a good idea for a winter marina hook up, mainly because the voltdrop is reduced to something bearable. If just summer light use (no heater for example and occasional kettle/hot plate) then 1.5mm core is OK for a typical 16A marina max supply. Though if you are looking for 10 years of use then possibly someone would advise finding a similar cable but with tinned cores. For the 16A shore connection plugs/connector I would suggest check they are at least IP44 rated (GW60004H 16A 2P+E 240V PLUG IP44 as an example).

For inside boat cabling some might say that cable with tinned cores has it merits, I would say it depends how long you expect it to last. If 10s of years then maybe tinned copper core cable has some merit. If it could easily replaced in ten years time then maybe non tinned would be just fine. As it is not exposed to UV then PVC sheathed cables would suffice but maybe Artic flex (I have not checked it, just relying on Paul's advise above).

By the way, I am not a professional marine electrical installer.

 

[prv]

Connect [the consumer unit] to the shore power socket with some 2.5mm arctic cable.

I believe the standard says this connection either has to be shorter than 1m or protected in rigid conduit. You may not be subject to the standard, but this still seems sensible to me if the cable's running through a deck locker that has all sorts of things shoved into it and potentially shifting around. I did mine in conduit to prevent it being yanked out of the back of the socket as the packed dinghy drops in, or chafed through by an anchor fluke resting against it, or whatever.

Pete

 

[Gixer]

Thanks,

Channel Sailor - Is that the same type of unit that Paul recommends but with a 16amp MCB instead of the 32amp? Thanks for the detailed response BTW.
prv - From the socket in the locker the cable goes straight though the bulkhead and into the aft cabin where I plan to fit the RCD, distance must be less than 50cm.

Just to be clear, from the input socket to the RCD, 2.5mm cable and from the RCD to the twin socket 1.5mm? I'll never run a kettle, hot plate or TV, etc from those. Most will be a drill, battery charger (for now ) and a 1 foot tubular heater.

 

[PaulRainbow]

I believe the standard says this connection either has to be shorter than 1m or protected in rigid conduit. You may not be subject to the standard, but this still seems sensible to me if the cable's running through a deck locker that has all sorts of things shoved into it and potentially shifting around. I did mine in conduit to prevent it being yanked out of the back of the socket as the packed dinghy drops in, or chafed through by an anchor fluke resting against it, or whatever.

Pete

The ISO states:

7.2.2 A manually reset trip-free circuit-breaker shall be installed within 0,5 m of the source of power or, if
impractical, the conductor from the source of power to the panel-board circuit-breaker shall be contained within a
protective covering, such as a junction box, control box, enclosed panel-board, or within a conduit or cable trunking
or equivalent protective covering. If the location of the main shore-power inlet circuit-breaker exceeds 3 m from the
shore-power inlet connection or the electrical attachment point of a permanently installed shore-power cord,
additional fuses or circuit-breakers shall be provided within 3 m of the inlet or attachment point to the electrical
system in the craft, measured along the conductor.

I am not subject to following the ISO, neither is the OP, but, as you rightly say, it is sensible to follow it.

 

[PaulRainbow]

Thanks,

Channel Sailor - Is that the same type of unit that Paul recommends but with a 16amp MCB instead of the 32amp? Thanks for the detailed response BTW.
prv - From the socket in the locker the cable goes straight though the bulkhead and into the aft cabin where I plan to fit the RCD, distance must be less than 50cm.

Just to be clear, from the input socket to the RCD, 2.5mm cable and from the RCD to the twin socket 1.5mm? I'll never run a kettle, hot plate or TV, etc from those. Most will be a drill, battery charger (for now ) and a 1 foot tubular heater.

The consumer unit Channel Sailor posted is fine, it might work out a few quid cheaper than the Screwfix one i linked to, the 16a MCB is only £3.99, so it'll depend on how much you have to pay for post, as opposed to a local collection, but either will be fine.

I would use 2.5mm for the shore power lead, more robust as much as anything. You can use 1.5mm or 2.5mm inside the boat, in terms of current capacity, but i'd stick with the 2.5mm.

 

[prv]

The ISO states:

Thanks, I was only half-remembering it

Sounds like the OP complies by default anyway due to the short distance.

Pete

 

[Gixer]

While I've got you guys.
You've now got me looking at a permanent battery charging solution, I do like the idea of plugging in the shore power and it all just happening.

At the moment I only have two small 65ah batteries, one for engine and one for domestics. I might add another 65ah battery for domestics (130ah bank) but need to see how I go. I'm getting a BMV-700 for Christmas so can monitor my usage.

Is this a bit overkill for my needs, it seems quite expensive for a charger?
Victron Blue Smart IP22 Bluetooth Battery Charger - 12V 15A, 3 output

 

[Blueboatman]

For what it is worth
I have exactly the spec suggested by Paul R.
Seems fine after some 10odd years of all year round useage ( edit, but plugged in @ various uk outlets ?)

 

[BabaYaga]

The unit first linked to by the OP has double pole MCB, unlike the other suggestions as far as I can see.
Double pole over current protection is sensible for anyone that might use their boat in an unpolarized system, like continental Europe.
It is also, if IIRC, an ISO requirement.

 

[JumbleDuck]

But there is no stock for a month, most of the stuff I can source but the RCD I'm not sure about. I really want to get the right one. Anyone got any recommendations?

Will your two new sockets be near each other and will you be running anything else off main? My boat has a double socket with integral RCD connected to an outside hookup point, which seems like a neat solution to me - although I didn't fit it and I don't actually use it. For maritime purposes its seems a shame that consumer units have to be rustable steel nowadays.

 

[Gixer]

Will your two new sockets be near each other and will you be running anything else off main?

The outlet will be one dual 13a socket. I wasn't planning to run anything else off the main but am now looking at a integrated charging solution.

Is double pole only for continental Europe then? I did see this but honestly don't really understand what it means.

 

[JumbleDuck]

The outlet will be one dual 13a socket. I wasn't planning to run anything else off the main but am now looking at a integrated charging solution.

Thanks. I am in a similar situation ... I'd like to have a fixed battery charger and have been thinking of resuscitating my mains system - which I abandoned when I lost the link-up cable, which in any case was rather unwieldy. Fitting a consumer unit for the sake of something which draws 1A seems a bit overkill-y, so I am thinking of having the charger wired in on the 12V side and just plugging it in to the socket when needed.

 

[PaulRainbow]

A slightly alternative suggestion:-

This fuse box: "Building Supply 30mA RCD + 16 Amp + 6 Amp MCBs (tlc-direct.co.uk)". This has in the box I think is a more a more useful 16A MCB

Good suggestion, might work out a few £££s cheaper

For the shore connection I would suggest 3CORE HO7RN−F 450/750V BS7919 Black sheath flex (i don't think it is available in Orange). I have not checked the detail but this cable seems to have more small strands within each core compared to some flex cables. I have not looked at the difference to Artic flex mentioned above. I do notice the usual PVC sheathed cables are affected by UV and they are very stiff to handle in the winter (possibly not rated below 0 degrees C anyway).

HO7RN−F and Arctic cable has the same, or thereabouts, diameter strands. The Arctic cable would be more susceptible to UV than HO7RN-F, but unlikely to be an issue. Arctic cable is rated for use down to about 40c, could be why it's called Arctic Another possible issue with HO7RN-F is that it can leave black marks, the outer covering is rubber.

 

[PaulRainbow]

The unit first linked to by the OP has double pole MCB, unlike the other suggestions as far as I can see.
Double pole over current protection is sensible for anyone that might use their boat in an unpolarized system, like continental Europe.
It is also, if IIRC, an ISO requirement.

Only In unpolarized systems.

 

[Gixer]

I am thinking of having the charger wired in on the 12V side and just plugging it in to the socket when needed.

That's what I do now. I have a CTEK MXS screwed to a bulkhead which I plug into one of the 13amp sockets. The only difficulty is I can't change both batteries at once so have to alternate plugging one and then the other. No great hardship but always looking at a better solution

 

[PaulRainbow]

That's what I do now. I have a CTEK MXS screwed to a bulkhead which I plug into one of the 13amp sockets. The only difficulty is I can't change both batteries at once so have to alternate plugging one and then the other. No great hardship but always looking at a better solution

You could fit a VSR, that way both batteries get charged from the mains charger and the alternator. How does the alternator currently charge both batteries ?

 

[JumbleDuck]

That's what I do now. I have a CTEK MXS screwed to a bulkhead which I plug into one of the 13amp sockets. The only difficulty is I can't change both batteries at once so have to alternate plugging one and then the other. No great hardship but always looking at a better solution

I have just discovered that inline RCDs exist, so that may be my solution. Regulations schmegulations.