reverse polarity

[Bglad]

Originally Posted by Verytricky

So you have to keep them as three seperate wiring systems?

What about when you are not connected to the land wire?

I have a generator that automatically connects neutral and earth - if that is on a boat is this dangerous?

Have another go at reading Marshmat's post #12 he has it right. Don't worry about your generator since all the current is inboard it is appropriate to have the green ground and neutral connected. Usually the transfer switch takes care of separating the two when you switch between ship and shore power whether manual or automatic.

[Lt. Kludge]

Originally Posted by marshmat

Land-based systems commonly ground the neutral at the building's main distribution box. This is normal and correct in most terrestrial AC distribution systems.

For TN-S Electric Distribution systems Yes. But for other systems such as the IT (being phased out from parts of Europe) The voltage/current from "Neutral" conductor to ground can be lethal.

Many Electrical Safety Standards today are migrating to the view that with regard to electric shock hazard, the neutral conductor is treated as a phase conductor.

[Verytricky]

I have been around for quite a few years, and I have never come accross an IT system anywhere in Spain, Germany, UK or South Africa. All have been TN systems, usually TN-S, occasionally ( like in my current house ) TN-C.

Most offices in my area are TN-C-S.

Some high tech offices are TT, and most computer centers are TT with RCD.

I dont think IT systems are even legal in the EU. Even the very very old EU standards prevented an IT system from being installed.


I believe Australia and Newzealand use TN-C as their 'standard' ( PME system )