Installing a New Consumer Unit (Electrical)

**MattFS218** · 14-10-2008, 10:33 AM

I found out my girlfriend's house in Isan did not have a ELB or Safe-T-Cut, so on this trip up we purchased an ABB consumer unit with MCB and RCCD (the price was only a little more for the consumer unit plus Main CB, RCCD, and MCB than a Safe-T-Cut device).

We are running a hot water heater, air con, computer equipment (with 22 in monitor), tv, fridge, etc.

The sales woman said, and I've read on this this board and others that this setup is equivalent to using a Safe-T-Cut device.

Anyway, now I'm in Isan, and am trying to set this thing up...the gf, says her brother-in-law and uncle are qualified enough to install it, and the sales lady of the consumer unit says it is semi idiot proof to install, and of course I'm watching over their back.

The diagram I am following is

the consumer unit looks like

Does this setup look correct? The electrical lines going to the appliances have 2 wires inside, the live one will be the one connected directly to the Mini Circuit Breakers, but where does the other line connect? In the picture I've circled in blue where I, and the technician in the store said the other line to the appliances (the neutral line) will connect, can someone just verify this is correct. The official digram does not seem to indicate where the other wire connecting to the appliances should connect

Also, what size wires should I use for the internal connections within the consumer unit, I assume the larger the better since inside the unit can be transfer lots of power, but I couldn't find anywhere it recommended a size.

Lastly, is copper the only recommend grounding method? The brother-in-law says he has some non-copper, iron (i think) stick that could be used as a ground. How deep into the ground should this be?

Okay, thank you very much for your help, maybe I'm being too cautious, but I think I need to be with electricity in Isan. Thanks again for your help.

--matt

**dirtydog** · 14-10-2008, 10:58 AM

Use the same size wire as is being used already, the neutral goes to the right as you have indicated in the picture, the left is for your earths, a 1.5meter copper rod is 100 odd baht.

**phunphin** · 14-10-2008, 12:11 PM

".the gf, says her brother-in-law and uncle are qualified enough to install it,"
In thailand anyone with enough fingers to pick up a screw driver is qualified.

**MattFS218** · 14-10-2008, 05:14 PM

Originally Posted by dirtydog

Use the same size wire as is being used already, the neutral goes to the right as you have indicated in the picture, the left is for your earths, a 1.5meter copper rod is 100 odd baht.

Thanks dirtydog...

A few more quick questions if you don't mind...

What is the suggested way for making contact between the incoming/outgoing wires and screws/Mini Circuit Breakers/RCD/Main Circuit breakers? Am I right in assuming the ends of the wires should be stripped to the copper, and then tightened accordingly. Would it be helpful to sort of loop the copper wire around the screws to ensure better contact?

I intend to install a ground regardless, but all of my electronics equipment only has 2 plugs (ie no ground). Given this, is there a benefit to having the Consumer Unit be grounded?

Also, will creating this grounding at the consumer unit cause any problems with our hot water heater, which I believe is already separately grounded? I know in curtain circumstances having multiple grounds can be inappropriate.

And the last question, it seems sorta odd (to a newbie at least) that the neutral back to the meter and the ground connection share the same connection. Is this normal?

Thanks again for all your help...I know to a Thai everyone seems qualified to install this stuff, that's why I'm asking here!!! I may owe my life to Teakdoor for the valuable information it provides. Thanks.

**SandMike** · 15-10-2008, 12:30 AM

You'll probably find that you can't wrap your wires around the screws - they are used to clamp the bare wire inside the circuit breakers, and the neutral and earth bars.

I note that your photo doesn't show the copper bars linking the RCCD & the MCB's that the diagram shows - you were given these by the shop weren't you ??

It is absolutely necessary that the consumer unit has a very good ground connection - it is this connection that ensures the RCCD will trip.

Briefly, the RCCD monitors the live & neutral supply wires into the house. As long as the current in and out balances, all is well. If there is a fault in a piece of unearthed equipment, and the body of the equipment becomes live it will still not trip. It only trips when a path to earth for some of the current is available (i.e. you grab hold of it). At this point the RCCD detects an imbalance in the current flows and operates.

The ground on your hot water heater will allow the RCCD to trip if there is a fault, and before you grab hold of the shower head.

As for the last question, yes this normal. This connection will help to ensure a good return path for any current flowing through you, and helps to ensure that the RCCD sees the current imbalance.

As you say above, most people think they are qualified to install this stuff, and usually they don't understand the operating principles. The trick is to make sure that it operates correctly when you need it.

Hope this helps

**HINO** · 15-10-2008, 07:44 AM

Just finished reading this thread. Nice to see someone upgrading to more modern and safe electrics. It seems Matt that you have limited experience with electrics and wiring. With that in mind and you are looking for the right way and the safe way I may recommend that you go to this link and absorb all that you find there. I think many things will be more clear.

The Thailand Wiring Page

**More Volts Igor** · 15-10-2008, 08:49 PM

Originally Posted by MattFS218

Am I right in assuming the ends of the wires should be stripped to the copper, and then tightened accordingly. Would it be helpful to sort of loop the copper wire around the screws to ensure better contact?

Sorry mate, but if you have to ask these questions you should NOT be attempting to install a consumer unit, the result could be a fire hazard or worse lethal.

**MattFS218** · 15-10-2008, 08:57 PM

Originally Posted by SandMike

I note that your photo doesn't show the copper bars linking the RCCD & the MCB's that the diagram shows - you were given these by the shop weren't you ??

I have 1 copper bar, but it only links the live from the RCD to the Mini Circuit Breakers (as shown in the diagram). On this subject, for the other connections within the unit, like from the connection from the Main Circuit Breaker to the RCD (both live and neutral), the connection from the neutral screw-in bar to the RCD, and the neutral connection from the Main Circuit Breaker to the Ground screw-in bar, what size wire should I be using? From the mini circuit breakers to the appliances I'm using either 1.5mm or 2.5mm sized wiring.

HINO's guide recommends the ground wire to the ground rod should be 4mm minimum. My girlfriend's house only has a 5amp meter, but I don't want to have to change the internal wiring of the consumer unit should we upgrade to a larger meter. The Main Circuit Breaker and RCD I purchased were the 40amp variety (the price was the same and I figured it would give us future room for expansion). Can I please get a little more guidance on the wire size I should be using for the internal connections within the circuit breaker.

Thanks SandMike for your help, and thanks HINO, I've read almost that whole website.

--matt

**MattFS218** · 15-10-2008, 09:00 PM

Originally Posted by More Volts Igor

Sorry mate, but if you have to ask these questions you should NOT be attempting to install a consumer unit, the result could be a fire hazard or worse lethal.

I'm not installing it, a "qualified" Thai person is installing it and I'm looking over their shoulder...

as I've looked over both the grounding and electrical of my professionally installed a/c and water heating units done by Thais, I'm pretty sure I'd rather be trusting my own electrical knowledge than that of a professional Thai. Thanks for your concern tho.

**mikehunt** · 15-10-2008, 09:32 PM

My comments in yellow.

Originally Posted by SandMike

It is absolutely necessary that the consumer unit has a very good ground connection - it is this connection that ensures the RCCD will trip.

An RCD/RCCD does not require any special earth cable in order for it to work correctly. The reasons why are as you said in your below statement. Not withstanding this, it is always advisable to provide a proper earth to any installation. In order for this earth to work correctly, an "Earth Fault Loop Impedance" test must be carried out, which NEVER happens in Thailand along with the Insulation Resistance test & the Polarity test.

Briefly, the RCCD monitors the live & neutral supply wires into the house. As long as the current in and out balances, all is well. If there is a fault in a piece of unearthed equipment, and the body of the equipment becomes live it will still not trip. It only trips when a path to earth for some of the current is available (i.e. you grab hold of it). At this point the RCCD detects an imbalance in the current flows and operates.

On a side note, only a professional electrician knows the importance of wire twisting & the connections thereof. Unfortunately, I have not met/seen or known of a professional Thai electrician.

You may find a "qualified" farang willing to help you but it may cost accordingly.

**dirtydog** · 15-10-2008, 09:43 PM

Originally Posted by MattFS218

I'm pretty sure I'd rather be trusting my own electrical knowledge than that of a professional Thai.

No offense, but you have proved your knowledge to be zilch, I would recommend going to your local electric store and asking them to get someone sent round to look over shoulders.

**SandMike** · 15-10-2008, 10:38 PM

^^

Mikehunt, I agree that an RCCD does not need an earth connection to operate.

However I contend that without a ground connection bonded to the neutral, the return earth path may be of a high enough impedance that the current flowing to ground (And hence the imbalance) is insufficient to cause the RCCD to operate (it is also entirely possible that even with a ground connection this is the case).

I fully agree with your point that ANY electrical system should be properly earthed (and moreover earth connections must be present in all the socket outlets). I believe this is now a mandatory requirement for new installations in Thailand.

**MattFS218** · 16-10-2008, 08:48 AM

My hot water heater was installed prior to my installation of my consumer unit. The hot water heater was installed with it's own ground, which appears from the surface to be a steel bar into the ground.

My question is, since I've installed the consumer unit ground, would it be better to dig up the hot water ground, and connect it to the consumer unit ground? or leave it as is?

Thanks.

**HINO** · 16-10-2008, 09:54 AM

Comment in yellow

Originally Posted by MattFS218

Originally Posted by SandMike

I note that your photo doesn't show the copper bars linking the RCCD & the MCB's that the diagram shows - you were given these by the shop weren't you ??

I have 1 copper bar, but it only links the live from the RCD to the Mini Circuit Breakers (as shown in the diagram). On this subject, for the other connections within the unit, like from the connection from the Main Circuit Breaker to the RCD (both live and neutral), the connection from the neutral screw-in bar to the RCD, and the neutral connection from the Main Circuit Breaker to the Ground screw-in bar, what size wire should I be using? From the mini circuit breakers to the appliances I'm using either 1.5mm or 2.5mm sized wiring.

HINO's guide recommends the ground wire to the ground rod should be 4mm minimum. My girlfriend's house only has a 5amp meter, but I don't want to have to change the internal wiring of the consumer unit should we upgrade to a larger meter. The Main Circuit Breaker and RCD I purchased were the 40amp variety (the price was the same and I figured it would give us future room for expansion). Can I please get a little more guidance on the wire size I should be using for the internal connections within the circuit breaker.

Matt it sounds to me like the load you have on this 5 amp supply is way too much. Someone "very" qualified needs to review this installation as you mentioned a water heater plus lighting and other appliances. The whole house needs a higher amp meter and supply based on your description. The size of the earth cable to the copper rod needs to be sized to at least the same as the heaviest supply conductor from the pole. But a minimum of 4 mm. Connecting a MEN link can be more dangerous if the other PEA connections on this supply are not using a MEN link. Do not use the MEN link unless you can be sure the entire area uses the MEN system.

Thanks SandMike for your help, and thanks HINO, I've read almost that whole website.

--matt

See comments in yellow

**MattFS218** · 16-10-2008, 02:03 PM

The guy answering the phone at the local EGAT office did not know specifically what a MEN system was (said both M.E.N., MEN, and Multiple Earth Neutral), but he did say it was OK to install a ground at our house here in Isan. I went outside, and walked down the street, about 1 in every 3 electrical posts has what appears to be a connection, connecting a wire into the ground (I'm assuming this is a ground).

What is the typical term of a MEN system (maybe written in Thai).

--matt

**MattFS218** · 16-10-2008, 02:11 PM

HINO,

Other posts on boards seem to indicate that the "5 amp meter" is actually capable and safe(?) to pull 2-3x the amount for support up to 15Amp. My air-con and water pump is actually hooked up to a different totally isolated meter from the empty house next door. So is 15 amps (5 meter) for fridge, hot water, computer, monitor, lighting seem more reasonable?

**HINO** · 16-10-2008, 04:01 PM

Matt, I have given you some words of "advice". I am in no way a "certified electrician" to be giving you any direction based on limited information on this site.

You appear to know a little but not enough. Every answer from anyone here on this site will only create confusion and possible conflicting ideas and answers.

I will no longer participate in this discussion as I think your headed down a very dangerous road. You need exact info that I am not qualified to give.

I hope you find a certified and qualified local electrician that can solve this issue.

Good luck

**MattFS218** · 16-10-2008, 04:54 PM

I understand now why my question about wrapping the wire around the screw to ensure a better connection is stupid.

I'm using 10mm2 wires for the connections within the CU, they are the same sized wires as being fed from the meter. The 10mm2 wires are really thick, and with the insulation makes them very difficult maneuver.

I'm not connecting the ground until I find someone in the local EGAT office that can answer my question about MEN.

Please understand, that in the developed world I'd never be doing this myself. My alternative to doing this, without the use of a "fully fully fully qualified technician" is because currently there is no RCD. So I understand its a hazard that I'm even considering doing this, but my alternative is to use appliances totally unprotected.

Here is a new picture

**dirtydog** · 16-10-2008, 06:09 PM

^What the fok have you done there?

**MattFS218** · 16-10-2008, 06:15 PM

I give up...it seems everyone complains about how bad thai electricians are, then when I try to do something about it to protect my family, and ask questions to plea for help (since I know I'm not knowledgeable on the subject), people refer me back to the same thai electriains who are so notourious in the first place.

DD, please help me out, and let me know why I'm so stupid with the wiring I have done above.

**MattFS218** · 16-10-2008, 06:22 PM

I'm using 10 mm2 wiring...

I realize it looks bad, but is this because I'm using outdoor insulated wiring for inside the CU box? I don't have a lot of resources available to me at the minute, but the electrical store in the Ampur, only has 4 mm2 wiring, so instead we took the 10 mm2 wiring from the meter feed. (they had 10mm2, but it was the type consisting of smaller copper wires twisted together)

I've consulted 3 other boards, plus made several phone calls to the engineer at HomePro I purchased it from, and the local EGAT office.

**dirtydog** · 16-10-2008, 06:33 PM

That just looks so wrong, I always use square "D" consumer units, you got 2 bars and your breakers, your earth bar you just connect all your earths and then a cable run to your copper rod outside, mains live and neutral into your main breaker, then take all your lives from your other breakers and all your neutrals from your neutral bar, as for the safety trip breaker the only times I have worked on them is to take them out due to old aircons etc tripping them, generally the customer will turn them to the highest setting as they keep tripping anyway, great for using on single electrical items, ie one each for each water heater, one for each hob etc, but in a main consumer unit they just become problematic with older high usage electrical appliances, anyway, I trust hard earthed wires more than a safety cut or earth leakage breaker.

**Deke** · 16-10-2008, 08:16 PM

You are on the right track. Just hook it up as shown in your drawing.

I assume that your 20 amp breaker is for an air conditioner and the 16 amp breakers are for outlets/lighting?

If you can find a standard copper-clad ground rod, that is best. Otherwise, a long length of galvanized pipe or similar will work in a pinch.

**MattFS218** · 16-10-2008, 09:24 PM

Originally Posted by Deke

You are on the right track. Just hook it up as shown in your drawing.

I assume that your 20 amp breaker is for an air conditioner and the 16 amp breakers are for outlets/lighting?

If you can find a standard copper-clad ground rod, that is best. Otherwise, a long length of galvanized pipe or similar will work in a pinch.

Thanks for the comment Deke,

The 20amp breaker is actually for the hot water heater. The ABB sales person gave us a chart of which size circuit breaker/wire size to use with each appliance. Surprisingly or not up to a 12000 BTU a/c they suggest only needs a 16 amp breaker, but the 3500W hot water heater needs 20 amps and 2.5 sq mm wiring.

**Deke** · 16-10-2008, 09:42 PM

Originally Posted by MattFS218;801126[/quote

Thanks for the comment Deke,

The 20amp breaker is actually for the hot water heater. The ABB sales person gave us a chart of which size circuit breaker/wire size to use with each appliance. Surprisingly or not up to a 12000 BTU a/c they suggest only needs a 16 amp breaker, but the 3500W hot water heater needs 20 amps and 2.5 sq mm wiring.

That sounds right (who am I to argue with ABB).

It looks to me like you've got it.

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