Consumer Unit basics

[Forkinhades]

It's definitely an RCD with overcurrent protection. So yes RCBO it is

[wpcoe]

Thanks! That's one less issue to contend with.

If I were to find a twin RCBO to the one in my condo, would it work as a drop-in replacement in the townhouse from my OP?

[Crossy]

If I were to find a twin RCBO to the one in my condo, would it work as a drop-in replacement in the townhouse from my OP?

Sadly no, the condo unit is a Schneider plug-in device, the unit in the OP is DIN mount, not compatible

[ianbardon]

Hi guys,  some very interesting comments on here cheers, I love your website Cossey, being as I have not started to build anything at this mo, and will be going back to the UK before I start building, so a new consumer unit is one thing I will be bringing back with me, I have the following in mind plus any other bit you can recomend.

BG CUDP16610 10 Way Insulated 17th Edition Dual RCD Consumer Unit

Stylish modern design will fit in going un-noticed around the home!

Fully loaded complete with 10 MCB's 2 x 63a 30ma RCD's and 1 x 100A Main Switch from one of the market leaders in the wiring accessories and circuit protection BG Nexus.

Complete with the following
3 x 6 Amp MCB's
2 x 16 Amp MCB's
4 x 32 Amp MCB's
1 x 40 Amp MCB's
2 x 63 Amp 30mA RCD's
1 x 100 Amp Main Switch
2 x Blank Covers
Circuit Identification Stickers
Installation Guide

Key Features
Modern Stylish Design
Quick and simple to install
Accepts upto 7 ways protected by Either RCD
Ready To Install
10 Way
Fully Loaded
Material Plastic
Insulated
Dual RCD Protection

Dimensions: 390mm Length
                    230mm Height
                   115mm Depth
 

[Crossy]

Do you get a choice of the MCBs to install?

 

Thailand doesn't use ring-finals so unless you can use the 32A and 40A on water heaters / aircon they are redundant, 16A are a bit small for outlet circuits (20A is the norm), but will probably be OK except for the kitchen, 6A fine for lighting.

 

You'll have to replace the main switch with a 2-pole MCB to suit your meter, we don't have service fuses in Thailand so a simple switch won't suffice.

 

Plenty of DIN consumer units available here so unless the one you're looking at is particularly competitively priced or styled to fit with your potential décor I wouldn't bother (is it heavily discounted because it doesn't comply with BS7671 Amdt 3?).

[ianbardon]

I do have the choice of MCB, when I look at the local one I can not make head nor tail of them, so an item from UK seemed a better option, I am not too bothered about  any redundancys  or price, as you right point out its your life  and how do you put a price on that, not ready for the grim reaper just yet, lol . I noticed that we dont have service fuses , wow

what is the unit you would fit ?

[Crossy]

We have 3 (yes three) ABB SystemPro 16-way DIN units, they came from HomePro. As supplied they are completely bare so you have the choice of installing whatever you like.

 

If you have a choice of MCBs and the price is good, get the unit from the UK but do read this document (ok look at the pictures) http://crossy.co.uk/Handy Files/groundwire.pdf particularly the routing of the incoming neutral via the ground bar (same as the US NEC). This is the Thai implementation of MEN (in UK speak PME) and you won't pass your PEA inspection if you don't do it this way.

[ianbardon]

can you explain what your 3 are doing ? I have plans to build a modest bungalow 2 bed 1 bath, open plan kitchen and dinner/lounge, so only 2  A/C

[Crossy]

 

Ok, the electrical nerve centre, it's evolved somewhat rather than being properly planned hence the bits tacked on :)

 

Right at the top in the small box is our MOV whole-house surge arrestor. The black thing next to it is the transmitter for a CurrentCost energy monitor.

 

Top consumer unit:-

50A 2-pole incoming breaker (we have a 15/45 meter)

6A MCB for the transfer switch

6A MCB for the digital meter

2 x 40A MCB for sub mains to the other CUs

Over/under unit for the transfer switch

Omron relay (part of the transfer switch)

4-pole transfer contactor

16A Genset MCB

 

Mounted on the trunking:-

Genset auto/manual switch (so I can stop it at night and run on the UPS)

Overall load meter

Analog meter on the incoming supply

 

Middle consumer unit:-

RCD

Secondary over/under (protects the aircons when the genset isn't running as the transfer switch doesn't have an "off" position).

Five 20A MCBs for aircons (only 3 in use at present)

40A sub-main to the workshop, garden supply and irrigation pumps.

Contactor to disconnect the water heaters when on genset.

Three 40A MCBs for on-demand water heaters.

 

Bottom consumer unit:-

Another secondary over/under unit.

Bypass for the over under, to get emergency power on if the mains is available but out of range and the genset isn't running.

Five 20A outlet circuits. Two for the kitchen, the washer/dryer get their own circuit.

10A MCB for the water pump, it also controls the electric gates, koi pond, sala lighting, security lights and the LED floodlights in the garden (the power was in a convenient place, there's a separate box near the gates with several RCDs and the lighting controller).

6A for terrace lights and the house mounted LED floodlights.

Two 6A lighting circuits **

A final 10A outlet circuit **

 

** The last three breakers are supplied from a UPS so essential lighting and technology stays on whilst the genset starts for uninterrupted Thai soap viewing.

 

[ianbardon]

ok cheers for the break down, soaps and catoooons very important

[richard1977]

On 1/11/2016 at 6:12 AM, Crossy said:

EDIT I see quite a few suitable units on AliExpress which will ship to Thailand.

Something like this http://www.aliexpress.com/item/DPNL-1P-N-63A-230V-50HZ-60HZ-Residual-current-Circuit-breaker-with-over-current-protection-RCBO/1086847618.html?spm=2114.01020208.3.225.w71REf&ws_ab_test=searchweb201556_1,searchweb201644_2_10001_10002_10005_10006_10003_10004_62,searchweb201560_1,searchweb1451318400_6149 would do the trick.

 

are 4kA RCBOs and MCBs okay for thailand?  i was looking in homepro and most of the local stuff seems to be 6kA or above.  i'd rather save some money and buy the cheaper stuff from aliexpress, but only if 4kA is safe enough to use.

[r136dg]

Blast from the near past. One of my many go to threads for my electrical;-)

I too would like to hear the answer to your question. I have 2 distribution boxes, 1st din rail than a plug-in CU. Most of my RCBO's are Schneiders in the CU; however, I have one (exactly what your inquiring on) in the din rail box & would like to add more. No doubt, very cheap next to the Schneiders. 

The one I have seems to work fine. Got a diagnosis of that circuit when hooking it up. There was a shared neutral & it wouldn't work till I found & corrected it.

Looking forward to response on your post Richard!

[Crossy]

2 hours ago, richard1977 said:

are 4kA RCBOs and MCBs okay for thailand?

Assuming your main incoming breaker can handle the prospective fault current then that's the one to worry about. The subsequent units are invariably lesser beasts.

 

Important Note. That RCBO I quoted from AliExpress, despite what the little drawing says, is a 1P+N. i.e. it does not switch the neutral. So you shouldn't use it as your sole source of supply isolation.

 

[richard1977]

On 9/25/2017 at 11:09 AM, Crossy said:

Assuming your main incoming breaker can handle the prospective fault current then that's the one to worry about. The subsequent units are invariably lesser beasts.

 

 

thanks!  i have another question.  i was looking at this RCBO to use as my incomer (i have a 15/45 meter):

 

https://www.aliexpress.com/item/50A-2P-RCBO-RCD-Circuit-Breaker-DE47LE-DELXI/32584903881.html

 

i noticed it has a cover over some extra terminals.  can i remove this cover if i want to supply some unprotected (leaky) circuits?

is this the correct way to use this type of RCBO?

 

 

 

 

i'm guessing that if the RCD trips, the grey "R" switch will switch off the protected circuits, but the unprotected circuits will still be on.  the big red switch will switch everything off (big red switch turns everything off on overcurrent or when switched manually).  is this correct?

[Crossy]

@richard1977 I think you are nearly right.

 

There is certainly nothing to stop you putting "leaky" devices on the MCB only as you suggest.

 

BUT

 

Looking at the diagram on the unit it suggests that the RCD side will trip the MCB to open the circuit. So everything goes off.

 

If you want some unprotected circuits I would buy a separate MCB and RCD (no need for it to be an RCBO) and configure as a conventional split board.

[Cashboy]

I am confused !!

I keep seeing electrical drawings of the Earth connected to the Neutral.

 

In Thailand I see a live and neutral coming from the meter into the houses.

I do not understand why you would connect the neutral to the earth in the consumer unit especially if you are going to use RCDs.

 

Surely the earth rod in the ground is connected to the earth and the neutral from the mains supply connected to the neutral and no connection between the earth and neutral?

 

 

 

[bankruatsteve]

7 minutes ago, Cashboy said:

I am confused !!

I keep seeing electrical drawings of the Earth connected to the Neutral.

 

In Thailand I see a live and neutral coming from the meter into the houses.

I do not understand why you would connect the neutral to the earth in the consumer unit especially if you are going to use RCDs.

 

Surely the earth rod in the ground is connected to the earth and the neutral from the mains supply connected to the neutral and no connection between the earth and neutral?

 

 

 

Crossy has explained this at least a dozen times so I'll try to give him a break.  Check out some of the other posts.  That is how "MEN" is implemented in Thailand.  The earth rod is still connected to the the ground bar.  Neutral joined with earth here is upstream any RCD so not affected.

[Cashboy]

5 minutes ago, bankruatsteve said:

Crossy has explained this at least a dozen times so I'll try to give him a bread.  Check out some of the other posts.  That is how "MEN" is implemented in Thailand.  The earth rod is still connected to the the ground bar.  Neutral joined with earth here is upstream any RCD so not affected.

Can you confirm that you are telling me the correct way to wire the consumer unit is as follows:

1) connect the earth rod to the earth in the earth block in the consumer unit

2) connect the neutral supply from the mains to the neutral block in the consumer unit

3) connect a wire from the neutral block to the earth block in the consumer unit

 

And after doing that; the RCDs will still work perfectly?

 

 

[bankruatsteve]

2 minutes ago, Cashboy said:

Can you confirm that you are telling me the correct way to wire the consumer unit is as follows:

1) connect the earth rod to the earth in the earth block in the consumer unit

2) connect the neutral supply from the mains to the neutral block in the consumer unit

3) connect a wire from the neutral block to the earth block in the consumer unit

 

And after doing that; the RCDs will still work perfectly?

 

 

1. Yes.

2. Not in a "MEN" installation.  The neutral is connected to the earth bar for "MEN".  I don't know why but that's the Thai spec.

 

An RCD, MCB, etc. does not "know" what is happening in front of it - only the load side is detected.

 

[Cashboy]

7 minutes ago, bankruatsteve said:

1. Yes.

2. Not in a "MEN" installation.  The neutral is connected to the earth bar for "MEN".  I don't know why but that's the Thai spec.

 

An RCD, MCB, etc. does not "know" what is happening in front of it - only the load side is detected.

 

Please clarify:

I am building a new house and will have a new mains supply from the government that I assume will be a live and neutral.

Am I doing a normal connection that you state (connecting a wire from the earth block to the neutral block) or an "MEN" installation where I do NOT connect a wire from the earth block to the neutral block?

My consumer unit will have 10 MCBs;  2 x 5 MCBs with each bank of 5 MCBs protected with an RCD.

 

[bankruatsteve]

6 minutes ago, Cashboy said:

Please clarify:

I am building a new house and will have a new mains supply from the government that I assume will be a live and neutral.

Am I doing a normal connection that you state (connecting a wire from the earth block to the neutral block) or an "MEN" installation where I do NOT connect a wire from the earth block to the neutral block?

My consumer unit will have 10 MCBs;  2 x 5 MCBs with each bank of 5 MCBs protected with an RCD.

 

Check out the pinned "IMPORTANT ..." and the "RCD" topic in this forum.  Your PEA should advise whether you have "MEN" or not but my understanding is that all new installations should be.  It is suggested that the main 2-pole breaker on a CU is a RCBO.  If you are thinking UK practice, read the "RCD" post as that has just been covered there.

[Cashboy]

15 minutes ago, bankruatsteve said:

Check out the pinned "IMPORTANT ..." and the "RCD" topic in this forum.  Your PEA should advise whether you have "MEN" or not but my understanding is that all new installations should be.  It is suggested that the main 2-pole breaker on a CU is a RCBO.  If you are thinking UK practice, read the "RCD" post as that has just been covered there.

For your information; the Consumer Unit I have in Thailand is a UK purchased Schneider with two RCDs with each RCD covering 5 MCBs.  I bought it because I knew that the Schneider MCBs are available in HomePro also.

 

[bankruatsteve]

1 minute ago, Cashboy said:

For your information; the Consumer Unit I have in Thailand is a UK purchased Schneider with two RCDs with each RCD covering 5 MCBs.

 

Well, that's not going to do it in Thailand.  What is protecting the mains from over-current?

[Cashboy]

11 minutes ago, bankruatsteve said:

Well, that's not going to do it in Thailand.  What is protecting the mains from over-current?

I just read the RCD thread and now get what you are talking about.

I also brought to Thailand  from the UK, a 63 Amp Wylex fused box with some spare 60 amp fuses that I was going to connect the mains live and neutral to before the Consumer Unit.

That would do wouldn't it?

[Crossy]

20 minutes ago, Cashboy said:

That would do wouldn't it?

Perfect as a main incomer, PEA will love you, maybe

 

They may want to see the N-E link before that switch, resist (or change it once the inspector has left). I like to be able to completely isolate my supply from the big bad PEA world.

[bankruatsteve]

13 minutes ago, Cashboy said:

I just read the RCD thread and now get what you are talking about.

I also brought to Thailand  from the UK, a 63 Amp Wylex fused box with some spare 60 amp fuses that I was going to connect the mains live and neutral to before the Consumer Unit.

That would do wouldn't it?

I have no idea what is inside of that but if it is "fused" what will you do if/when the fuse burns out?  A common switch used here to isolate the mains is a "Chang" DPST knife blade that is fused at 60 amps and would be OK for 15/45.

 

[Cashboy]

3 minutes ago, bankruatsteve said:

I have no idea what is inside of that but if it is "fused" what will you do if/when the fuse burns out?  A common switch used here to isolate the mains is a "Chang" DPST knife blade that is fused at 60 amps and would be OK for 15/45.

 

A 60 Amp Cartridge Fuse is in it.

I took 5 spares to Thailand.

[bankruatsteve]

1 minute ago, Cashboy said:

A 60 Amp Cartridge Fuse is in it.

I took 5 spares to Thailand.

Well, Crossy likes it so there you go.

[Crossy]

3 minutes ago, Cashboy said:

A 60 Amp Cartridge Fuse is in it.

I took 5 spares to Thailand.

You may even be able to get the fuses (without the bolt on blades ) here

[Cashboy]

9 minutes ago, Crossy said:

Perfect as a main incomer, PEA will love you, maybe

 

They may want to see the N-E link before that switch, resist (or change it once the inspector has left). I like to be able to completely isolate my supply from the big bad PEA world.

I was thinking this was the solution to isolate the mains supply before the consumer unit.

I bought them second hand for 500bt in the UK and the spare fuses are 110bt on Amazon in the UK.