Electrical main board connection of Neutral to Earth, and Electrical wiring reminder

[jojothai]

I have moved into a house in Hua Hin last year and had some problems with the electrics.

House was built over 10 years ago. 

The board was tripping out all electrics for a short time periodically.

I had solar installed last December and have had to figure out all the wiring because at the time there were a number of issues identified.

I think its been well stated that the electrical systems installations here can be a problem.

As a reminder to people, what I found shows that they do anything they want with no respect for standards or safety.

Use any color of cable and bits of wire they have, making multiple joins changing color and sometime size.

All kitchen on one circuit 32 amp breaker, hob oven and water heater included, Oven and hob are 6.4 + 2.6 KW (although unlikely to use all at once, we rarely use more than a few KW)

No separate breakers. Wire size 2.5sqmm from roof, 4sqmm cable connected to 2.5 at back of units looks better but most should be at least 6mmsq.
Earth looks ok in kitchen but too small (1.5 sqmm) and then I found not connected in roof.

Water heater 6KW was on wiring 2.5 sqmm and one wire dropped to 1.5 sqmm. No separate breaker. Earth appears to be connected ok at 1.5sqmm.

When used with other appliances occasionally it was tripping the whole system for a short time when initially switched on. The mains is 15/45 amp.

I can see the sharp surge on my solar app.

Air conditioners not earthed. Earth wire looks ok to two units but earth not connected in roof. Then also, no earth to outside compressor.
Two AC's connected together onto 32 A breaker without individual breakers. 

Lots more lesser problems, but i think the above illustrates how bad some important things can be.

 

I am nearly complete on adding the wiring and breakers.

Work has been necessary on the main board and that's where I note my initial topic for any advice / comment please
In the main board there is a direct wire connection from the earth strip to the neutral strip.

I checked online and it seems to be correct. As follows:

Should I be concerned about bonding the Neutral-to-Ground Bond in the main panel?

Neutral-to-ground bond is needed to properly operate the circuit breakers.  Over Current Protection Devices (OCPD) such as circuit breakers and fuses actually require a short and intense INCREASE in electrical current (a short) in order to detect the fault and cut the circuit off.    Without a sharp and drastic increase in electrical flow, a fault could go on without triggering a circuit breaker to stop the flow.  This actually occurs quite often and can be measured easily by checking the amount of current flowing on your ground conductor.  It should be less than 1-amp in most cases.  If the current flowing on a grounded conductor is higher than an amp, and you are not in a high-voltage (600V+) environment, it typically indicates an erroneous neutral-to-ground bond somewhere in the system.

 

I therefore assume it is ok for the connection here in Thailand, unless I get advice to the contrary.

Thanks in advance for any advice. It may also be useful for others to know.

 

 

 

[Crossy]

Yes, a N-E bond in the distribution board / consumer unit is correct.

 

It confuses many but in reality, many other countries do the same. In Aus and the US the links are visible, in the UK the link is in the service head and not accessible.

 

The diagram below came from this PEA document (my translations) Groundwire Mk2 book-Manual.pdf

 

Note the routing of the incoming neutral via the ground bar, this is the Thai implementation of MEN (Multiple earthed Neutral). This connection must be before any RCD/RCBO devices or it will cause them to trip constantly.

 

If you require an electrical inspection this is how the inspector expects it to be done.

 

Have you included RCD or RCBO devices in your revised system?

 

 

Wikipedia has a good description of the various earthing systems 

https://en.wikipedia.org/wiki/Earthing_system 

Thailand is generally TNC-S with MEN.

 

 

[jojothai]

Thanks crossy,

Comments much appreciated.

I have been busy all day on some formal work tasks. Just heading back home.

Will look at this more tomorrow morning.

[jojothai]

15 hours ago, Crossy said:

Yes, a N-E bond in the distribution board / consumer unit is correct.

 

It confuses many but in reality, many other countries do the same. In Aus and the US the links are visible, in the UK the link is in the service head and not accessible.

 

The diagram below came from this PEA document (my translations) Groundwire Mk2 book-Manual.pdf

 

Note the routing of the incoming neutral via the ground bar, this is the Thai implementation of MEN (Multiple earthed Neutral). This connection must be before any RCD/RCBO devices or it will cause them to trip constantly.

 

If you require an electrical inspection this is how the inspector expects it to be done.

 

Have you included RCD or RCBO devices in your revised system?

 

 

Wikipedia has a good description of the various earthing systems 

https://en.wikipedia.org/wiki/Earthing_system 

Thailand is generally TNC-S with MEN.

 

 

I just realised that i need to know what size of wire should be used from N To E.

Looks 2.5 sqmm.

Is that enough?!

I have a 15 - 45 amp board.

I think the earth wire to ground is 4 sqmm. Have to check but then should the E to N  be the same size 4 sqmm.

Also noticed that the wire from incoming main cable N to the N bar is 6 sqmm.

If i use up to 40 amps, is it big enough. 

Does it need 10 sqmm?

Thanks for your advice.

[MAF666]

On 2/7/2023 at 4:59 AM, Crossy said:

Yes, a N-E bond in the distribution board / consumer unit is correct.

 

It confuses many but in reality, many other countries do the same. In Aus and the US the links are visible, in the UK the link is in the service head and not accessible.

 

The diagram below came from this PEA document (my translations) Groundwire Mk2 book-Manual.pdf

 

Note the routing of the incoming neutral via the ground bar, this is the Thai implementation of MEN (Multiple earthed Neutral). This connection must be before any RCD/RCBO devices or it will cause them to trip constantly.

 

If you require an electrical inspection this is how the inspector expects it to be done.

 

Have you included RCD or RCBO devices in your revised system?

 

 

Wikipedia has a good description of the various earthing systems 

https://en.wikipedia.org/wiki/Earthing_system 

Thailand is generally TNC-S with MEN.

 

 

Seeing my link from E to N was not connected, I made up a link.

Can confirm Crossy’s advice that the RCCB will trip constantly if N incorrectly terminated.

Just gotta figure out how to change it…

[sometimewoodworker]

9 minutes ago, MAF666 said:

Seeing my link from E to N was not connected, I made up a link.

Can confirm Crossy’s advice that the RCCB will trip constantly if N incorrectly terminated.

Just gotta figure out how to change it…

Randomly adding a E -> N link, unless you are an actual electrician and have the equipment and training is a poor idea. It seems from your questions that you don’t have that, so it maybe OK but maybe not

[MAF666]

Have a PEA guy who moonlights.

 I am not going to mess with it.

[sometimewoodworker]

2 hours ago, MAF666 said:

Have a PEA guy who moonlights.

 I am not going to mess with it.

Wise choice, he is probably actually trained and competent. We to know a PEA guy who is trying to move up to EGAT but hasn’t passed the tests yet and he is certainly competent.

[jojothai]

On 2/7/2023 at 8:09 PM, jojothai said:

I just realised that i need to know what size of wire should be used from N To E.

Looks 2.5 sqmm.

Is that enough?!

I have a 15 - 45 amp board.

I think the earth wire to ground is 4 sqmm. Have to check but then should the E to N  be the same size 4 sqmm.

Also noticed that the wire from incoming main cable N to the N bar is 6 sqmm.

If i use up to 40 amps, is it big enough. 

Does it need 10 sqmm?

Thanks for your advice.

FYI, The incoming wire from earth lead was 4mmsq. From checking codes i believe that is the minimum i should have.

Then i have changed the E to N wire to the same 4mmsq.

For the neutral main connection with 45 amp board, all the code advice i see indicates that it should be 8mm sq.

I have therefore changed the 6mm wire to 10mmsq which is the next size i can get above 6mm.

I have completed the changes today when i was changing the breaker sizes to address the problems i see in the initial installation.

I spoke to somebody electrical i know and they agreed what i was doing as ok.

If you may be experienced to advise any different then i would be pleased to hear any other advice thanks.