Connecting Earth to Neutral - Where is best?

[Cashboy]

I understand that I have to connect the Earth to the Neutral to comply with Thai electrical regulations.

 

From what I have seen so far this is done in the consumer unit.

 

I have three consumer units in my house/office.

They are all connected from my Changeover switch where the government mains and generator supply come in.

 

Can I connect the Earth to the Neutral in the electric box (changeover switch) above?

 

And if so from the Earth to which Neutral point?

 

i.e. before or after the 63 Amp MCB.

 

 

 

 

 

[johng]

Here is how they wired mine..

which I don't think is 100% correct ? as the Neutral can't be isolated via the (not) "safe-t-cut" breaker.

some of the apartments have the Live and Neutral reversed

( notice both live and Neural wires are black  )  So they are switching Neutral instead of Live !!!!

[bankruatsteve]

I'm "pretty sure" MEN in Thailand will have the incoming N attached to the Earth bar.  I can't find Crossy's diagram (OK, I didn't try very hard) but the above photo seems not right at all.

[johng]

[bodga]

26 minutes ago, johng said:

Here is how they wired mine..

which I don't think is 100% correct ? as the Neutral can't be isolated via the (not) "safe-t-cut" breaker.

some of the apartments have the Live and Neutral reversed

( notice both live and Neural wires are black  )  So they are switching Neutral instead of Live !!!!

Jesus that  looks  <deleted>,  nice bits  of  copper showing and so erm ......orderly.

[Crossy]

@Cashboy Make your MEN link (N-E connection) at the earliest point possible in your installation, in any case it must be before any RCD/RCBO.

 

@johng that's so nearly right. Assuming (dangerous) that green=ground and grey=neutral then move all the green wires to the left hand bus bar (fixed to the box) and all the grey wires to the right hand bus bar (on the insulators).

 

Verify your incoming polarity using a simple neon screwdriver before touching anything!!!

 

[johng]

5 minutes ago, Crossy said:

that's so nearly right. Assuming (dangerous) that green=ground and grey=neutral then move all the green wires to the left hand bus bar (fixed to the box) and all the grey wires to the right hand bus bar (on the insulators).

Thanks @Crossy  Yes your assumptions are correct, for my apartment  but in others  I've seen "they" used grey as live  and then reversed the polarity at the meter 

  "they" being the Government Housing Authority "electricians"

good job I don't have to check/correct the other 4,000 +  apartments ????

[Crossy]

1 hour ago, Cashboy said:

And if so from the Earth to which Neutral point?

 

If you have a permanent meter already then I would connect the neutral from the switched side of the incoming breaker to the earth bar in the box (where is the rod connected?).

 

If you don't have a permanent meter yet and so have to pass the PEA inspection you should connect the incoming neutral to the earth bar and from there to the incoming breaker.

 

I would be much happier being able to open both poles on the incoming supply before any connections to my local earth but the local regs don't permit that.

 

[johng]

54 minutes ago, bodga said:

Jesus that  looks  <deleted>,  nice bits  of  copper showing and so erm ......orderly.

Government Housing Authority "electricians"   they had 4000+  rooms to wire up so maybe rushed a bit ????

[Metropolitian]

Wiring in both is wrong.

Give me some minutes to come up with the right drawing.

Don't turn it on yet @Cashboy

[Metropolitian]

 

 

• This ESR Changeover switch, which can be assembled as crossover or changeover, has double-row busbar under it. So only one output, the Load Output.
• The big busbar is connected with the iron casing, this is the earth-busbar.
• The incoming neutral need to go to the earth busbar and then to the main breaker.
• Normally the N-out is connected to the neutral busbar (which is isolated from the iron casing) but in this setup only one wire so you can skip using the neutral busbar. (the purple lines is how the neutral wires usually are wired.
• I can see in the wiring that the wires that goes to the other consumer unit and the wires that goes to the generator shares the same pipe, right? In the drawing for conveniently I separated those wiring for easy understanding how the wires are wired.
• The earth ground rod goes is coming from below and is wired right.
• Make sure the generator set has a proper MCB.
• DO NOT connect the neutral wires to the earth bar in the other Consumer Units.
• Only in this unit the Earth and Neutral are linked, which make sense as the ground rod wire is also there.

 

Now in the current setup you need to do two things;

1. Move the neutral main wire to the earth busbar and a wire between the earth busbar to the Neutral IN at the bottom of the main breaker.
2. Move the wires from the generator, and connect it on the top with the label GEN-IN

 

 

 

 

The Earth busbar:

E.   Connect the earth ground rod here.

B.   Connect the -INCOMING NEUTRAL- here

B.   Connect a Neutral Bypass from here to the N-IN at the main breaker.

6..1  Connect the Earth wire that goes to the other (Consumer) Units here. (Don't forget the gen.)

 

 

 

 

Edited July 20, 2020 by Metropolitian
missing n-link

[Metropolitian]

Just now, Metropolitian said:

Now in the current setup you need to do two things;

1. Move the neutral main wire to the earth busbar and a wire between the earth busbar to the Neutral IN at the bottom of the main breaker.

 

DANGER.

 

BE AWARE :  That the incoming main wires are connected directly to the grid, there is nothing that protects you.

Only do when you are sure, which means measure measure measure and even then not believe the measuring equipment blind.

With a proper test (neon screwdriver which glows on contact with a live/hot wire or using the right gear) you can tell which one is real live wire. (Always assume that stickers are never 100% telling the truth)

 

Never touch it. Only the neutral wire need to be changed.

 

In doubt, even the slight percentage of doubt, let a spark do it.

 

Everything behind the main breaker can be isolated and are more 'safe' to handle with.

(assuming there are no children there and the wife is sent to the shopping mall )

[Metropolitian]

5 hours ago, johng said:

Here is how they wired mine.

????‍♂️  The first breaker looks like it was broken and now only held together with screws.

The big green wire, if connected with the ground earth rod, to be moved to the earth bar the one with the big screw.

This is for sure, no doubt from my side.

 

BUT the remaining green wires -and- the grey wires...  I don't know how they are wired in the sockets on the walls.

 

If in the sockets the grey wires are used as earth and the green wires are neutral. Then you only need to move the big green wire in the CU if that wire come from the earth ground rod.

If in the sockets the grey are connected with neutral prongs and the green used as earth, then move the wires according the picture below.

 

 

[Metropolitian]

And remove the sticker with 'N' from the back plate ????

[GregTN]

I just checked mine and the neutral is definitely not bonded to my ground rod.  If I understand correctly it is acceptable and safer in my case to connect them after the main breaker but PEA requires them before the main breaker for an inspection.  If my understanding is correct then what size wire should I use for this connection on a 50 amp service?

 

[bankruatsteve]

30 minutes ago, GregTN said:

I just checked mine and the neutral is definitely not bonded to my ground rod.

The ground bar in the CU should be connected to the ground rod.  Commonly done with 10mm².

Refer to diagram posted above.

Use 10mm² for other mains connections in the CU.

[GregTN]

57 minutes ago, bankruatsteve said:

The ground bar in the CU should be connected to the ground rod.  Commonly done with 10mm².

Refer to diagram posted above.

Use 10mm² for other mains connections in the CU.

Will it work correctly if the connection between the ground and neutral bars is made after the main breaker?  I could cut the power and easily make that connection myself if so.

[bankruatsteve]

14 minutes ago, GregTN said:

Will it work correctly if the connection between the ground and neutral bars is made after the main breaker?  I could cut the power and easily make that connection myself if so.

Not sure what your issue is. (?)  The PEA diagram is how they want it to work correctly.

[GregTN]

2 minutes ago, bankruatsteve said:

Not sure what your issue is. (?)  The PEA diagram is how they want it to work correctly.

Thank you for the advice.

[Crossy]

1 hour ago, GregTN said:

Will it work correctly if the connection between the ground and neutral bars is made after the main breaker?  I could cut the power and easily make that connection myself if so.

 

It's not "to code" so won't pass a PEA inspection (for a permanent supply). Also, if your main breaker happens to be an RCBO or Safe-T-Cut then it won't stay "on" with that connection.

 

Do be aware that unless you are certain that MEN has been implemented in your area you are better off NOT making that N-E connection. You can get a good idea if MEN is available by looking at the power poles in the street, if the neutral (usually the top wire of the 4 LV wires) is grounded every 3rd or 4th pole you're good to go, if not leave it as is.

 

If you don't have an RCBO or Safe-T-Cut device (look for a "Test" button) you should seriously consider adding one for protection from electric shock.

[GregTN]

2 minutes ago, Crossy said:

 

It's not "to code" so won't pass a PEA inspection (for a permanent supply). Also, if your main breaker happens to be an RCBO or Safe-T-Cut then it won't stay "on" with that connection.

 

Do be aware that unless you are certain that MEN has been implemented in your area you are better off NOT makeing that N-E connection. You can get a good idea if MEN is available by looking at the power poles in the street, if the neutral (usually the top wire of the 4 LV wires) is grounded every 3rd or 4th pole you're good to go, if not leave it as is.

Thank you Crossy