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K_V_B · 18-02-2015, 00:41

Quote:

Originally Posted by FlyingCloud1937

I don't know....weenk

read this and tell me

http://www.google.com/url?sa=t&rct=j...85970519,d.cGU

Reading this my first thought is: Where is the RCD?

AFAIK an whole boat RCD or (ELCI as they seem to call it your side of the pond) is now mandatory in new instalations in the US as well.

Note: The image I posted doesn't have an RCD as well, but I posted it to illustrate that tying N and PE together at the secondary of an isolation transformer is not "against code" as one poster thought might be.

FlyingCloud1937 · 18-02-2015, 00:58

Lets consider the first and most potential fault.

The boat is on the HARD. Plugged into shore power.

Assuming, the shore power is properly earthed.

Then the boat must not be properly earthed.

So, when owner(we all know whom that is)gets shocked, We must assume that resistance to earth was greater between the boat cable then the prop and the HUMAN to the boat yard(real earth).

If not the case?

So now lets go into the next fault potential?

Lloyd

Quote:

Originally Posted by DotDun

Hmm, the inverter doesn't work if there is a 120v potential on the shorepower. Even then, the inverter opens the shorepower neutral/hot when it's putting out 120v.

And the transfer switch leaves the shore power neutral connected to the boat while in 'Gen' position??? If so, it's a huge problem. The transfer switch opens (at minimum) the H and N, hence the N/G tie in the generator is of no consequence.

No, the only source reference to earth ground is shorepower, neither the generator or inverter is reference to earth ground with the boat sitting on blocks.

You need to trace back to the source.

K_V_B · 18-02-2015, 01:07

Quote:

Originally Posted by FlyingCloud1937

Lets consider the first and most potential fault.

The boat is on the HARD. Plugged into shore power.

Assuming, the shore power is properly earthed.

Then the boat must not be properly earthed.

Why not? There is no reason why you cannot earth the boat as well. That way you are not dependent on the shore power to be properly earthed.

Quote:

So, when owner(we all know whom that is)gets shocked, We must assume that resistance to earth was greater between the boat cable then the prop and the HUMAN to the boat yard(real earth).

An RCD wouild already have trippped and disconnected the power even before anyone touched the prop.

FlyingCloud1937 · 18-02-2015, 01:08

Well,

A battery is only so big, so at some point you must connect to a shore side charger. The Inverter assist is most likely your only advantage, when charging.

Or you have a KW hungry boat, which in the end will mean you need to feed those bats,

that is unless U have a perfect design? Much like a perfect Transformer/battery, either you have perfected the unity.

Lloyd

Quote:

Originally Posted by K_V_B

I would not plan to use shore side power assist. I would plan on having a large enough inverter, and use gen set to assist if needed.

What is the problem?

FlyingCloud1937 · 18-02-2015, 01:13

Quote:

Originally Posted by K_V_B

An RCD wouild already have trippped and disconnected the power even before anyone touched the prop.

Not if the fault was at the line voltage prior to the RCD.

The RCD would not know of this fault.

Lloyd

FlyingCloud1937 · 18-02-2015, 01:25

National Electric
Code are consistent when they require that
the neutral and ground only be connected at
a “newly derived source.” In our case, this
means that the connection is made at the
marina’s electrical service entrance (which
is a transformer ashore) and at the output
of an operating generator, operating inverter
(invert mode), or isolation transformer
aboard the boat. When the operating source
of power is aboard the boat (a generator, operating inverter
(invert mode),
this neutral-ground connection is required
to be aboard the boat. And when shore power
is the boat’s power source, there must be
no neutral/ground connections on the boat.

K_V_B · 18-02-2015, 01:27

Quote:

Originally Posted by FlyingCloud1937

A battery is only so big, so at some point you must connect to a shore side charger. The Inverter assist is most likely your only advantage, when charging.

Or you have a KW hungry boat, which in the end will mean you need to feed those bats,

that is unless U have a perfect design? Much like a perfect Transformer/battery, either you have perfected the unity.

My "perfect" boat is one where I can meet all my energy needs also when on the hook. In such a boat I would install an Inverter/Charger combi such that together with a generator they can power everything I want powered.
So in most cases the inverter would power everything. The generator comes on when the batteries need charging, or when the AC demand is higher than the inverter can produce by itself.

The battery charger would be mostly there to keep the batteries charged if I leave the boat in a harbor somewhere for an extended period.

But this is all hypothetical right now. First need to sell the company...

K_V_B · 18-02-2015, 01:32

Quote:

Originally Posted by FlyingCloud1937

Not if the fault was at the line voltage prior to the RCD.

What kind of fault could that be?

K_V_B · 18-02-2015, 01:33

Quote:

Originally Posted by FlyingCloud1937

National Electric
Code are consistent when they require that
the neutral and ground only be connected at
a “newly derived source.” In our case, this
means that the connection is made at the
marina’s electrical service entrance (which
is a transformer ashore) and at the output
of an operating generator, operating inverter
(invert mode), or isolation transformer
aboard the boat. When the operating source
of power is aboard the boat (a generator, operating inverter
(invert mode),
this neutral-ground connection is required
to be aboard the boat. And when shore power
is the boat’s power source, there must be
no neutral/ground connections on the boat.

I know that. But I'm missing somehow what point you are trying to make here.

FlyingCloud1937 · 18-02-2015, 01:55

hypothetical, right is right, but

There is no Perfect Transformer...sorry if I mislead you.

There is no Perfect battery.

There is no Perfect generator.

There is no Perfect inverter.

There is no Perfect charger.

There is no Perfect solar Panel.

There is no Perfect, ...........

There is no Perfect BOAT, its all a compromise.

Lloyd

Quote:

Originally Posted by K_V_B

My "perfect" boat is one where I can meet all my energy needs also when on the hook. In such a boat I would install an Inverter/Charger combi such that together with a generator they can power everything I want powered.
So in most cases the inverter would power everything. The generator comes on when the batteries need charging, or when the AC demand is higher than the inverter can produce by itself.

The battery charger would be mostly there to keep the batteries charged if I leave the boat in a harbor somewhere for an extended period.

But this is all hypothetical right now. First need to sell the company...

FlyingCloud1937 · 18-02-2015, 02:06

Don't sell the CO.

Live the Dream.

Lloyd

Quote:

Originally Posted by K_V_B

My "perfect" boat is one where I can meet all my energy needs also when on the hook. In such a boat I would install an Inverter/Charger combi such that together with a generator they can power everything I want powered.
So in most cases the inverter would power everything. The generator comes on when the batteries need charging, or when the AC demand is higher than the inverter can produce by itself.

The battery charger would be mostly there to keep the batteries charged if I leave the boat in a harbor somewhere for an extended period.

But this is all hypothetical right now. First need to sell the company...

**Dockhead** · 18-02-2015, 02:15

Quote:

Originally Posted by Miniyot

. . . IF the European standard were to be so much better and safer there would not have been 2.5 million people who received an accidental shock (350,000 severely injured, 22 killed) (2010 data for Great Britain, not all of europe).. . .

Actually it was 28 deaths in 2010 from low-voltage power in the UK: Policies and Research | Electrical Safety First

In the U.S., however, there were about 300 deaths from low-voltage power. That's about double the per capita rate in the UK, despite the fact that US power at 120 volts and 60 herz is far safer than the 230v 50hz power in the UK. Not just because of the voltage, but because lower frequency AC power is much more effective at stopping the heart, so more dangerous.

So I would say that the European standards are clearly much better, and I say that as a Yank.

Probably not just the electrical standards, but also the average quality of installations and wiring, and better workplace safety standards, but still.

K_V_B · 18-02-2015, 02:38

Quote:

Originally Posted by FlyingCloud1937

There is no Perfect BOAT, its all a compromise.

Hence the quotation marks around "perfect"

Sent from my iPad using Cruisers Sailing Forum

FlyingCloud1937 · 18-02-2015, 02:55

Yepper,

60 cycle seems to be at the perfect arithmeum, for the human heart.

Lloyd

Quote:

Originally Posted by Dockhead

Actually it was 28 deaths in 2010 from low-voltage power in the UK: Policies and Research | Electrical Safety First

In the U.S., however, there were about 300 deaths from low-voltage power. That's about double the per capita rate in the UK, despite the fact that US power at 120 volts and 60 herz is far safer than the 230v 50hz power in the UK. Not just because of the voltage, but because lower frequency AC power is much more effective at stopping the heart, so more dangerous.

So I would say that the European standards are clearly much better, and I say that as a Yank.

Probably not just the electrical standards, but also the average quality of installations and wiring, and better workplace safety standards, but still.