AC electrical problem getting crazy!!

[krush]

A "bifilial" (no "grounded conductor" at all) supply is a viable option and some European systems (in particular) are designed this way. There's a solid safety argument for doing it this way as the only way to get electrocuted with such a system is to bridge both sides of the supply.

Please provide a definition from a technical publication of the word "bifilial". 3phase delta, 240 single phase (in USA) doesn't "use a ground" either. Touch one of those wires while your feet are on the ground and tell me what happens......

Ground is a safety and a reference. If your feet are on the reference, you'll get zapped. If you are like a bird and feet are only on the energized line, you won't.

In such a system "safety ground" has no meaning as there is no reference between the supply and ground at all and thus no path for fault current to flow via a "safety ground."

O'relly? No reference, eh?

A boat with an isolation transformer can be wired this way internally (since the shore bolting will go no further than the primary winding of the isolation transformer) but if you do that you want two-pin outlets shipwide as there is no ground reference for safety purposes and implying that there is (or worse, interconnecting "grounds" but having no actual path for current down them!) would be a serious safety problem. Of course then you come on board with a device that has a three-pin cord designed for US shore-side use and you can't plug it in......

Houses in the USA for many years only had plugs with two prongs.

[Genesis]

Houses in the USA for many years only had plugs with two prongs.

Yes they did and grounded conductor was bolted to "earth"; faults could and frequently did kill people. In addition in a three-phase system there is an "earth" reference.

Reference (as requested):
http://www.cumminspower.com/www/lite...ingAC-1-en.pdf

System grounding refers to the intentional connection between a conductor of an AC power system and ground. The source of normal power for the system is typically a utility supplied transformer and the source of emergency or standby power is typically an owner supplied on-site generator set. The power system conductor connected to ground becomes the grounded conductor, which is typically the neutral circuit conductor on a 3-phase 4-wire system. System grounding, in other words, describes the practice of grounding one conductor of an AC power system.

An ungrounded system (where referencing any part of the supply to earth is assiduously avoided) provides no path to earth for someone coming in contact with one of the hot leads. Krush's claim that this is not true for contact with a 3-phase system is true but not for the reason he cites - in point of fact conventional 3-phase power does indeed reference the system to earth as the Cummins standby generator installation document referenced above shows.

Since I see the games won't stop this thread is closed.