One phase from three phase

[Cap Erict3]

Originally Posted by trifan

There is a reason it's called hertz and it ain't ol' Heinrich... it doesn't matter if it is 50 or 60, 240V lust hertz.

I think it's s play on words. Hurts as in pain.


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Looking for another pretty place to work on the boat.

[Wotname]

Originally Posted by Dockhead

Right, got it.

So do you agree with the principle, though? Is it true that I can take any one of the three phase pins, without regard to which one, and get 230v single phase power in the manner I propose? Or will it burn my boat down?

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Yep, the princple is correct. Your expertise in applying the principle will determine the risk of burning down your boat.

Be assured though that if there is a fire, it will usually only burn down to the waterline and as this is DIY project, you might consider going down with the ship if your expertise isn't up to the task

[StuM]

How's your insurance? Apart from the legality of doing your own "high voltage" wiring in many countries, insurance companies don't like claims where uncertified electrical work is involved. While you can do, I would get a qualified sparkie to wire up the converter and put an inspection tag on it, it shouldn't cost much.

[ebs001]

If the voltage is 380/230 then it is a wye connection. Then phase to neutral gives you single phase 230 volt. In the USA one of the commercial 3 phase voltage is 208/120, so when you have a120 v receptacle you can plug in the same sorts of loads that you plug in at your single phase house.

[um saudade]

It ain’t high voltage!



It could be wired delta or Y, does not matter all that much to you if phase to phase is 230volts and that’s what your boat requires. Just make sure you get 230 volts phase to phase and 0 volts to ground.This could be a wild leg delta, be careful!
If you have a isolation transformer and your system does not run the dock ground past the transformer in side (Ground is not common across the transformer primary to secondary, this is commonly how it’s done but some people have other ideas), you can use this power source.Pick up two phases and run them into your isolation transformer primary side.Run the dock ground to the isolation xformer.
You have a ground system on the secondary side that will protect you against ground faults.
The overcurrent protection should be provided at the dockside hook-up.Use the same overcurrent protection as will protect your pigtail and the wiring to the xformer primary.It should be a common trip.

Don’t hook anything else up.Don’t’ try this unless you have an isolation transformer.It still could be correct but without knowing the exact way the dock power is wired this is the only safe bet.

[med]

I think this is the usual European plug:-

[Compactorguy]

In the U.S. A three phase system say 480 volts 30 amp will consist of three hot lines 277 volts phased differently (think of the up and down curves you've seen on a scope, each curve is different than the other lines) this is so a three phase motor will have a continuing flow of power. There is no ground off those three lines. There is a separate ground line the forth usually green wire going to the plug. Take your tester and check voltage between ground and any one of the hots. If it is with 10% of your required voltage for example 220-240 for a 220 requirement. Make sure you are running proper fuse and breaker amperage protection being a commercial port you could have a supply of 100 or more amps when most marinas run 30 amps. 30 amps at 440 hurts like hell at a 100 amps your dead


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[nimblemotors]

How about this, get a 3-phase spotlight and shine it on your solar panels,
then no worries.

[um saudade]

I read that wrong, sorry.If you have 380 from A to B to C and every phase ( ABC) to neutral is 240 volts then it has to be wired as a wye secondary from the power transformer.
Then follow my previous instructions but run a hot phase and the neutral to the isolation transformer on the boat.All else stays the same.
Not sure how your plug is wired but should be able to change that configuration.Jjust keep track of the old wiring configuration and check the voltage coming out of the transformer to the boat power panel before you throw the mains.

[Cap Erict3]

Originally Posted by Compactorguy

In the U.S. A three phase system say 480 volts 30 amp will consist of three hot lines 277 volts phased differently (think of the up and down curves you've seen on a scope, each curve is different than the other lines) this is so a three phase motor will have a continuing flow of power. There is no ground off those three lines. There is a separate ground line the forth usually green wire going to the plug. Take your tester and check voltage between ground and any one of the hots. If it is with 10% of your required voltage for example 220-240 for a 220 requirement. Make sure you are running proper fuse and breaker amperage protection being a commercial port you could have a supply of 100 or more amps when most marinas run 30 amps. 30 amps at 440 hurts like hell at a 100 amps your dead


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Never do this!! The ground should never be used as a conductor.


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Looking for another pretty place to work on the boat.

[DeepFrz]

Run your generator!

[sy_gilana]

Hi Dockhead, some of the posts as well as your original question are correct. Measure with your MM between N and L1,2,3 and if you find 230V you're fine. The only thing I would add is to connect to the phase with the highest voltage, this will help phase balancing, there will inevitably be a voltage drop on the phases that are most heavily tapped elsewhere in the ring. If you take the lowest one, you could overload one phase and that will trip all three. You might find its only 1/2 a volt, but it tells a tale.
Go do it! I have done it in many marinas and commercial ports.

[captlloyd]

Don't know about Europe but in the US you can go to about any hardware/Home Depot and buy an inexpensive voltage tester. I would suspect they are available in Europe also. How is that for some information that you can really use.

[Djarraluda]

From the Pommy location, we can assume it is straightforward 3 phase, Earth and Neutral.
Probably, Multiple Earth Neutral system there, so yes, Earth and Neutral are the same voltage, so again, YES, wire from 1 phase to Neutral and include the separate earth.
Problem happens in the way the safety is arranged. There will be a Safety Switch, Earth Leakage Circuit Breaker or some other title for a gizmo that measures "what goes in, also comes out" If it does not, then it trips the circuit.
So, you can get (and cause) spurious safety trips if you get it slightly wrong.
Be safe and speak to the yard spark.

[Dockhead]

Originally Posted by sy_gilana

Hi Dockhead, some of the posts as well as your original question are correct. Measure with your MM between N and L1,2,3 and if you find 230V you're fine. The only thing I would add is to connect to the phase with the highest voltage, this will help phase balancing, there will inevitably be a voltage drop on the phases that are most heavily tapped elsewhere in the ring. If you take the lowest one, you could overload one phase and that will trip all three. You might find its only 1/2 a volt, but it tells a tale.
Go do it! I have done it in many marinas and commercial ports.

Thank you! Very useful information.