VicS
Well-Known Member
Double pole switching is required on a non-polarised system and that includes , perhaps more importantly, 2 pole circuit breakers or RCBOs
13A sockets onboard. Sanity check pls.
- Thread starter sarabande
- Start date
Stemar
Well-Known Member
Leaving aside the double gang/double pole issue, one thing to beware of with USB chargers is that, if they aren't boasting about the power output, it probably isn't very high, so may struggle with a hungry tablet. If that particular socket does give a power output, I missed it. Even when they do give it, it's often the combined output, so an output of 2A will give 2A with only one item plugged in, but only 1A each if you plug two in.
rogerthebodger
Well-Known Member
If you boat is set up as a normal UK mains installation with a live and neutral wiring. ( with the neutral connected to the earth line at the supply transformer. A single pole switch of OK as long as the switch is in the live side.
If your setup is a balanced system with no line earth connection generally a double switch is better as it cuts off both line conductors as either or both could be above earth potential so could give you an electrical shock
If your setup is a balanced system with no line earth connection generally a double switch is better as it cuts off both line conductors as either or both could be above earth potential so could give you an electrical shock
sarabande
Well-Known Member
Tks, VicS. I guess I need to take the MCBs out of the consumer unit and check their spec and that of the unit itself ?
I have a good idea that the previous owner was pretty clued up on electrics.
Stemar
And perhaps a set of purpose designed USB charging sockets rather than ones piggy backed onto a 13A socket ?
I have a good idea that the previous owner was pretty clued up on electrics.
Stemar
And perhaps a set of purpose designed USB charging sockets rather than ones piggy backed onto a 13A socket ?
Momac
Well-Known Member
For USB charging I fitted a USB socket in the 12Volt DC system, replacing the cigar lighter type socket. Its then possible to charge the phone or tablet without needing shore power .
My boat has standard domestic sockets for the battery charger and immersion heater which are in the lazarette.
My boat has standard domestic sockets for the battery charger and immersion heater which are in the lazarette.
GHA
Well-Known Member
Bear in mind , though, a tablet/phone etc will likely only draw 0.5A or less from a usb power source which isn't clever enough to set the data pins voltage so the device will pull more. My samsung tablet will only draw about 0.450mA from anything onboard but a samsung charger.
For 5v a quick test shows this buck converter to hold the voltage at 5v or slightly above up to ...... bish, can't remember! , think it was up near 2A @ 5v. More testing to be done
jielaite 5v - Google Search
oldmanofthehills
Well-Known Member
Double pole isolates supply completely when off. Useful perhaps at plug socket perhaps if fed from supply when you are not actually sure that the positive BX+ is actually correctly connected to that ,or is floating voltage system, thus the supposed negative may still have voltage to earth on it at the outlet. Unless you are in the habit of sticking fingers or metal object in the negative socket or wires connected to it, then it wont make any real difference.
More useful and indeed EU mandatory in the consumer unit when you switch off to isolate the rest system when changing wiring/sockets etc further down the line
Keith-i
Well-Known Member
The MCB’s will only break the live. The main switch in the fuse box should be double pole though.
PaulRainbow
Well-Known Member
Not sure why, you don't need dual pole circuit breakers. You do need a dual pole RCD, isolator switch or RCBO.
You'll need USB charging when away from shore power at some point, so may as well forget about the ones in the 240v outlets.
PaulRainbow
Well-Known Member
Only if they are single pole.
rszemeti
Well-Known Member
Our boat is equipped with 4 MCBs in the incoming feed, (sockets for, sockets aft, battery charger, water heater) ... and a convenient 4 way "lightswitch" to allow invidual circuits to be turned on and off.
Apparently the ideal place to put this is in the wet shower ... our surveyor didn't object, so I can only assume it is correct way to do it ....
Apparently the ideal place to put this is in the wet shower ... our surveyor didn't object, so I can only assume it is correct way to do it ....
VicS
Well-Known Member
Hopefully also an RCD
Beneteau381
Well-Known Member
yes, when you go foreign like us and find the marina is wired with live and neutral swopped. Single pole live switch and your appliance when switched off is still live!
Beneteau381
Well-Known Member
And if your rcd has gone tech and Mam tries to clean the burned toast out of the electric toaster with a knife, an interesting result!
PaulRainbow
Well-Known Member
Is she really that stupid to be cleaning the toaster with a metal knife whilst it is still plugged in ?
Beneteau381
Well-Known Member
Mine isnt but I do know some that are! One of them taught her child how to dry tea towels in a micro wave. It was interesting when the child and its friends decided to dry a hamster!
stuey_two
Well-Known Member
In many European contries double pole switching is universal and no-one has to care whether live and neutral are swapped. Appliance plugs can often be inserted correctly or reversed - noone cares.
Cautious UK caravanners carry and use a polartity checker {under £10 from Toolstation etc) because UK caravans typically use single pole sockets and caravan sites sometimes offer reversed polarity -as a no cost option!
RupertW
Well-Known Member
We do exactly that on the boat and have a live/neutral reverser made up, so we have stayed with single pole.
jdc
Well-Known Member
In many countries the mains supplied at marinas is 127V 3-phase, with Live and Neutral in 220V 16A or 32A sockets - ones we normally plug our shore-power cables into - being wired between two phases. Thus there is 127V between neutral and earth as well as between live and earth. So it might well be better to have both live and neutral switched in the 13A socket, and as the DP sockets don't seem any pricier or harder to come by than single-pole ones one might as well use them imho. (I still unplug before tinkering inside an appliance 'tho!)
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