Isolating Transformers, The Earth wire connection conundrum

[sailorchic34]

Originally Posted by pbiJim

Quote:
Originally Posted by chala
Here are two GFCI as you may notice each one have 3 wires. How do you connect them to yours two wires floating wiring?

Originally Posted by pbiJim

I would be interested to hear the response to this question from this gentleman's most vocal critics. I think that this is a valid & productive question. The correct answer to this question should be useful to anyone with an IT & a GFCI on their boat.




Chala is talking about GFCI. Dave is talking about RCD. The last GFCI that I wired had 3 connections, not two. Is everyone talking about the same thing here? Is a GFCI different from a RCD? Is the US version different from the EU version?

Even with the old 2 conductor (ungrounded) wiring in older homes, a 3 wire GFIC wired to two wires (hot/ neutral) will trip when the load on the two wires is unbalanced. The ground wire (3rd wire) is there for other portions of the electric code and does not effect if the GFCI will trip or not.

You can install a 3 wire GFI on a 2 wire IT, Just don't connect the ground.. Though the odds of it finding a ground loop and tripping is somewhat low. If you had a center tap on the IT you could use that as a floating ground (Not an earth)

oops Jedi beat me to it.

[FlyingCloud1937]

Originally Posted by sailorchic34

Even with the old 2 conductor (ungrounded) wiring in older homes, a 3 wire GFIC wired to two wires (hot/ neutral) will trip when the load on the two wires is unbalanced. The ground wire (3rd wire) is there for other portions of the electric code and does not effect if the GFCI will trip or not.

You can install a 3 wire GFI on a 2 wire IT, Just don't connect the ground.. Though the odds of it finding a ground loop and tripping is somewhat low. If you had a center tap on the IT you could use that as a floating ground (Not an earth)

oops Jedi beat me to it.

First and foremost, it's against every US code local and national to install a receptacle that includes a ground pin on a 2 wire system.

Pass/Fail...you fail

Lloyd

[s/v Jedi]

What I find funny is that people question if the gfci/rcd or whatever name is used in which part of the world, will actually work and prevent electrocution, while these devices are specifically developed for only that goal and nothing else. A fuse or breaker is developed to prevent fire and nothing else so not to prevent electrocution. Grounding is a terrible fix to make them trip (at very high amperages) in situations where risk of electrocution exists. The theory is okayish, but real world implementation is terrible.

As nice as rcd's are, the isolation transformer is a whole extra step towards safety. This does not mean they make AC power installations idiot-proof. It is always possible to create dangerous situations. Just like I can design situations where a stupid pencil leads to a lethal accident, I can also design something dangerous behind an isolation transformer. Grounding the output is one such stupid thing to do.

If it's a US boat and you only care about galvanic corrosion, you can follow the ABYC recommendations.

In all other cases, incl. US boats where one also cares for personal safety, it is better to install with no grounding of any IT output. If you also install gfci outlets (seperate rcd protection on each individual outlet) then you're even safe when some Damien-like figure tries to kill the crew with multiple designed faults over multiple locations gambling on metal parts and crew bodies to complete circuits.

There is no better protection method against accidental electrocution than the isolation transformer when the output is kept floating.

[s/v Jedi]

Originally Posted by FlyingCloud1937

First and foremost, it's against every US code local and national to install a receptacle that includes a ground pin on a 2 wire system. Pass/Fail...you fail Lloyd

The code also says that a ground rod rammed 30 feet into the ground must be used to establish ground when one can not be had from the grid. Explain how you do that at anchor.

[FlyingCloud1937]

OK, a one size does not fit all, as some on here recommended, each system has consequences.

Each system whether installed on land or in a boat must meet all of the directives to be made proper.

For instance. ISO 13297 which Gobo, and Jedi propose, requires the following:

11 Installation

11.3 An a.c. circuit shall not be contained in the same wiring system as a d.c. circuit, unless one of the following
methods of separation is used.
a) For a multicore cable or cord, the cores of the a.c. circuit are separated from the cores of the d.c. circuit by an
earthed metal screen of equivalent current-carrying capacity to that of the largest core of the a.c. circuit.
b) The cables are insulated for their system voltage and installed in a separate compartment of a cable ducting or
trunking system.
c) The cables are installed on a tray or ladder where physical separation is provided by a partition.
d) A separate conduit, sheathing or trunking system is used.
e) The a.c and d.c. conductors are fixed directly to a surface and separated by at least 100 mm.


Just missing one of these requirements, makes an IT installation unsafe, there are hundreds of nuance's in installing an IT aboard, miss just one and not only are you out of EC, you may just be creating a hazard aboard.

I'm sure those that advocate here that one size fits all, won't stand beside you in court, nor with their insurance carrier.

So in the end if you want to do it, do it by following the rules, which means that someone on the internet might be wrong.

Lloyd

[FlyingCloud1937]

Originally Posted by s/v Jedi

The code also says that a ground rod rammed 30 feet into the ground must be used to establish ground when one can not be had from the grid. Explain how you do that at anchor.

It's clear you haven't read any US Code.

Here ya go Fluke tells ya http://www.fluke.com/fluke/usen/solu...dingbasics.htm

Lloyd

[sailorchic34]

Originally Posted by FlyingCloud1937

First and foremost, it's against every US code local and national to install a receptacle that includes a ground pin on a 2 wire system.

Pass/Fail...you fail

Lloyd

Lloyd honey, We're talking boats here and NFPA 70/NEC does not actually cover boats. Its a building code and oddly enough, a boat is not a building. Do try to keep up. Its why we don't need that pesky ground rod, Jedi mentioned.

But it will still work as a GFI on a 2 wire IT (under the right improbable conditions) on a boat, which is outside US building codes.

Plus there are many many older homes, where owners have installed GFI on 2 wire systems. Not code no. But it still protects and really that's the important part now, isn't it.

As an aside, steam power plants, the boilers and piping bits are not covered by building codes either. Just an odd titbit.

As Jedi said, and I agree 1000 percent with him, a IT on a boat, while not protecting from every possible fault, does provide superior personal protection when installed properly.

Lastly, I'm a professional engineer and as such I can actually provide an engineering design that might fall outside the building codes. I've actually done that a time or two where the code did not address a particular issue, so long as I maintained life safety.

[sailorchic34]

Originally Posted by FlyingCloud1937

It's clear you haven't read any US Code.

Here ya go Fluke tells ya Earth grounding basics

Lloyd

Does not apply to boats Lloyd, which is where Jedi was coming from.

[pbiJim]

Originally Posted by goboatingnow

What specific law do you quote. ABYC is merely a recommendation , it's not code. European RCD and its associated ISO standards are law

Dave

Strange, according to this source, ABYC "recommendations" have been codified & actually ARE legally binding upon people in the US:

https://law.resource.org/pub/us/cfr/....E-09.1990.pdf

If I spend a little time digging, I can probably quote you some case law too.

[sailorchic34]

Originally Posted by FlyingCloud1937

OK, a one size does not fit all, as some on here recommended, each system has consequences.

For instance. ISO 13297 which Gobo, and Jedi propose, requires the following:

Actually ISO is a standard organization like ABYC or ASTM or any one of 100's out there. It's recommendations, not actually an enforced code. Not in the US anyway. Nice to have but not the only game in town. Nor is it a "CODE" as in enforcement, permits, etc. The NEC is the electrical CODE of the land. But it stops at the dock.

Really Jedi's an engineer, You don't think he knows what he's doing???

[sailorchic34]

Originally Posted by pbiJim

Strange, according to this source, ABYC "recommendations" have been codified & actually ARE legally binding upon people in the US:

https://law.resource.org/pub/us/cfr/....E-09.1990.pdf

Ah but 46 CFR deals with Shipping, The commercial type/ not recreational boats.

Title 46 of the Code of Federal Regulations - Wikipedia, the free encyclopedia

[FlyingCloud1937]

Originally Posted by sailorchic34

Ah but 46 CFR deals with Shipping, The commercial type/ not recreational boats.

Title 46 of the Code of Federal Regulations - Wikipedia, the free encyclopedia

Again you will be wrong.

Add to that parts of 33 & 47

Lloyd

[sailorchic34]

Originally Posted by FlyingCloud1937

Again you will be wrong.

Lloyd

Why???

Gee Llyod, I think you and Chala, went to the same charm school.

[pbiJim]

Originally Posted by sailorchic34

Ah but 46 CFR deals with Shipping, The commercial type/ not recreational boats.

Title 46 of the Code of Federal Regulations - Wikipedia, the free encyclopedia

A few weeks ago, I stumbled across some case law where a judge ruled on a lawsuit involving a yacht. He based his opinion on ABYC standards rather than electrical code provisions because in his opinion the ABYC standards better represented the real world needs aboard the boat. I'd need to do some serious digging to find it again, but I did read that recently. The judge relied on ABYC standards over actual code. That stuck out in my mind & even spooked me a bit.


Also, I'm certainly no lawyer, but the following passage from the opening page that I referenced in my last post made it sound to me like the ABYC stuff was to be enforced against all people in the US. This too is enough to spook me.

By the Authority Vested By Part 5 of the United States Code § 552(a) and
Part 1 of the Code of Regulations § 51 the attached document has been duly
INCORPORATED BY REFERENCE and shall be considered legally
binding upon all citizens and residents of the United States of America.
HEED THIS NOTICE: Criminal penalties may apply for noncompliance.

[FlyingCloud1937]

Originally Posted by sailorchic34

Why???

Gee Llyod, I think you and Chala, went to the same charm school.

Hey Chic,

You seem to miss my point.

As a licensed PE then you must realize the litigious way, aka the American Way.

Charm has nothing to do with it, until you play the charm card.

You, if in fact you're a licensed PE complete with E&O, and continue to meet the CEU's, must realize the need to do it right.

You are not allowed to go off grid, at one moment, than back on at the next.

Lloyd