st599
Well-known member
It hasn't. UK is 240, EU is 220, so the label says 230 +/- 10
What is the purpose of 2 shore power cables.
- Thread starter Irish Rover
- Start date
starfire
Well-known member
Used to be 240V plus or minus 6%, now 230V plus 10%, minus 6%.
So nominally 230V, but actually 240V
Elessar
Well-known member
Seastoke
Well-known member
Show me a label that says any plus or minus ,no forget it I have to work to BS7671 AM2 , some work to Google .
jakew009
Active member
That's also the reason 'widow maker' cables (ie. 2x 16A plugs that combine to make a 32A supply socket) are so dangerous.
Ignoring the fact that you have live pins exposed if only one leg is plugged in, if you end up connecting each leg to a different phase, the moment you plug the second plug in it will likely grenade in your hand
I thought that they generally kept all the sockets on the same post on the same phase for exactly that reason but I'm not a marina sparky.
Elessar
Well-known member
A 2x 16A to make a 32A is a potentially lethal device that should never exist.That's also the reason 'widow maker' cables (ie. 2x 16A plugs that combine to make a 32A supply socket) are so dangerous.
Ignoring the fact that you have live pins exposed if only one leg is plugged in, if you end up connecting each leg to a different phase, the moment you plug the second plug in it will likely grenade in your hand
I thought that they generally kept all the sockets on the same post on the same phase for exactly that reason but I'm not a marina sparky.
But what will happen if you plug it into 2 different phases?
A “hand grenade” as you suggest? No, it will trip an MCB at worst.
Why all this 3 phase scaremongering?
But you are 100% right about a 2x16A to 32A being dangerous.
But 32A to 2x16A is fine (though you should probably have 16A fuses in the plugs to be sure)
jakew009
Active member
I've never tested it but I bet you would get a pretty exciting bang as you plug the ceeform in, hence my 'grenade' scaremongering
The fault current that would flow would be massive. I imagine the RCD would trip before the MCB assuming it works.If you've ever cut through a live bit of twin and earth with a pair of snips you'll know what a bang it can make as the blade edge disappears. With 415V it's just twice as big a bang.
PaulRainbow
Well-known member
See post #47.I've never tested it but I bet you would get a pretty exciting bang as you plug the ceeform in, hence my 'grenade' scaremongering
If you've ever cut through a live bit of twin and earth with a pair of snips you'll know what a bang it can make as the blade edge disappears. With 415V it's just twice as big a bang.
If you connected two phases it would be 2 x 220v, but they wouldn't add up to 440v. All you do is to create a dead short on each phase, hard to say if the RCB or MCB would trip first, although a lot of marinas are using RCBOs these days.
jakew009
Active member
I don't understand that comment at all. In UK phase to phase voltage is 415V.
Elessar
Well-known member
It’s the sort of thing I’d like to testI've never tested it but I bet you would get a pretty exciting bang as you plug the ceeform in, hence my 'grenade' scaremongering
If you've ever cut through a live bit of twin and earth with a pair of snips you'll know what a bang it can make as the blade edge disappears. With 415V it's just twice as big a bang.
PaulRainbow
Well-known member
Only if correctly connected. Joining them together with the cable you described is trying to join two different phases in parallel.
jakew009
Active member
Define ‘correctly connected’?
jakew009
Active member
It’s the sort of thing I’d like to test
Yeah me too. But knowing my luck I’d take out the fuse in the cutout
Seastoke
Well-known member
Remember the earth in a marina is a TT system, and not from the transformer neutral.Yeah me too. But knowing my luck I’d take out the fuse in the cutout
Seastoke
Well-known member
Jake, the two 16 amp plug scenario cannot really happen in a marina as the post on the pontoon must be from the same phase.
rogerthebodger
Well-known member
My mooring electrical outlet has 4 blue 16 amp outlets and I have checked the phases on each 16 amp outlet and have confirmed they are all from the same phase so in my case so the only issue with 2 16 amp plugs and a 32 A socket would be if one plug plugged in and the second left out the second plug pins could be live and not protected
Elessar
Well-known member
The phases are not the issue . The danger, which is foreseeable, is as you unplug the cable the first plug you take out will have live pins.
Dangerous, potentially lethal and such a cable should never be made.
You describe this as “the only issue”.
It’s not.
It someone is working in the distribution box and has isolated one of the circuits feeding one of your dangerous connectors it will remain live.
st599
Well-known member
It also depends on where you are. With double pole switches and breakers in common use, when we test installations in the EU, it's quite common to have a phase neutral inversion.
Portofino
Well-known member
So it’s a bad idea to have twin 16 A leads on a boat when one 32 A will work safer ?
Doesn’t answer why they ( builders ) instal said method = twin 16 s when a 32 will do without the risks talked about ^ ?
Mines on a 15 M berth @ 32 A with one heavy 32 A shore power lead fwiw . The berths we get put in are generally 32 s .If not I carry adapters , or the marina send a sparky with a bag load after I surrender my passport as collateral in the Med .Eg they plonk us in a 24 M @ 64 A pedestal
14/15 M seems the cross over from 16 to 32 A .There’s always gonna be slight overlap boat size wise anyhow .
It how it’s dealt with by builders .
Doesn’t answer why they ( builders ) instal said method = twin 16 s when a 32 will do without the risks talked about ^ ?
Mines on a 15 M berth @ 32 A with one heavy 32 A shore power lead fwiw . The berths we get put in are generally 32 s .If not I carry adapters , or the marina send a sparky with a bag load after I surrender my passport as collateral in the Med .Eg they plonk us in a 24 M @ 64 A pedestal
14/15 M seems the cross over from 16 to 32 A .There’s always gonna be slight overlap boat size wise anyhow .
It how it’s dealt with by builders .
PaulRainbow
Well-known member
No, perfectly safe to have two 16a inlets on a boat, provided both are for independent systems.
The dangerous ones being talked about are cables that have 2 x 16a inlets to a single 32a outlet.