TNCS - USING NEUTRAL AS EARTH IN BOARD

[assegayer]

Im travelling abroad to a country that has no earthing arrangement and my friend would like me to do a bit of work on his house. My question is Whether or not i could create a link between the Neutral and Earth bar to create a tncs system.

I know it sounds strange but i have just been thinking for the past couple of days how they do it here in the uk. They do the same thing for tncs systems a link between neutral and earth.
Could someone shine some light on the subject as to why it cannot be done and how it can be done here then?

P.s i know a earth rod can be hit into the ground but want to explore all options.

Thanks

 

[hightower]

You won't get to the fault stage, as the RCD will operate as soon as any power is used.
Some of the return current will return to the power supply via the earth instead of via the neutral.
The RCD will see the imbalance between the Line and neutral and trip.

What earth? There is no earth, it has been linked to neutral to create a bodged TNCS

 

[Rpa07]

You've only got to think of the scenario of wrong neutral leg to wrong neutral bar or when you're working on a circuit switched off at the board but neutral not removed, so easy to trip if neutral and earth touch. The amount of imbalance needed through the RCD coils is minuscule to cause a trip. No way would the install be a happy install if @hightower 's scenario was attempted.

 

[hightower]

You've only got to think of the scenario of wrong neutral leg to wrong neutral bar or when you're working on a circuit switched off at the board but neutral not removed, so easy to trip if neutral and earth touch. The amount of imbalance needed through the RCD coils is minuscule to cause a trip. No way would the install be a happy install if @hightower 's scenario was attempted.

I'd argue quite the contrary - it would be too happy, and would render the RCD completely useless.

 

[Rpa07]

It's electrickery, it knows more than us! We're just wire monkeys! I understand your passion though - we need a "myth buster"

 

[westward10]

Might try this tomorrow, it a controlled environment obviously

 

[Deleted member 26818]

What earth? There is no earth, it has been linked to neutral to create a bodged TNCS

Of course there's an earth.
If there wasn't, then there would never be an earth fault and installing an RCD would be pointless.

 

[hightower]

Of course there's an earth.
If there wasn't, then there would never be an earth fault and installing an RCD would be pointless.

Have the read the original post? You're making no sense to me.....

 

[Wilko]

Hi - not wishing to step into a hole, but would not the luckless chap be standing on the earth and the earth fault current flow through him? This would unbalance the RCD in the usual way, if it had ever been able to stay on line to begin with as per Spin #45 and Rpa #47 thoughts.

 

[Wilko]

Might try this tomorrow, it a controlled environment obviously

Do it, you know you want to

 

[westward10]

Do it, you know you want to

It is my intention but for it to be a scientific thingy you would have to isolate the board from all sources of earth which may be impossible, you have the earthing conductor, bonds and all those circuits linked to extraneous parts like water heaters, boilers etc.. to lose. I see defeat before I start.

 

[Rpa07]

I had to like that twice because of your shaky fingers @westward10!
@hightower, the OP didn't mention any busbars or where it should be linked just that it can be linked.

 

[westward10]

Third time I have done this, yesterday I managed the same post 13 times! I agree I assume the op means before the board not within it.

 

[hightower]

Well he did specifically say bus bars in his first post, which I take to mean in the board.....

 

[westward10]

The experiment has taken place at a board with the earthing conductor disconnected and none of the circuits in contact with extraneous parts. With a link across the earth and neutral bars the board functions, as soon as you reintroduce the earth the rcd trips.

 

[westward10]

Forgot to say the rcd is as much as a chocolate teapot when connected like this