main breaker for 3 phase house

[motdaeng]

we just bought a "chang" consumer unit for 24 circuit.

at the cashier they gave us a free main breaker :
- is the quality of this man breaker ok ?
- do we now have to buy all circuit breaker also from the brand "chang"
- what brand can you recommend ?


thanks for your help

motdaeng_norththailand

[Bcgardener]

The breaker looks like a Chinese copy of a Schneider unit just branded Chang by some Thai importer. These copies vary from dangerous to okay depending on what company in China made them. Only way to really tell is to dismantle the breaker but that's not a good idea. The 100 amp rating is very high for a domestic installation so may not trip under some fault conditions, or at all if it is a poor copy. I would just treat it as a main switch and use breakers of a known quality for your individual circuits so they provide the protection.

[Crossy]

I'm with BC on this one.

"Chang" is a popular local brand known for their low cost.

Is the consumer unit already populated with breakers? If not then the Schneider / Square-D plug-in modules should fit and are of known quality.

A 100A 3-phase supply does seem somewhat over the top, how big is your mansion?

Also if you are not having a 30/100 meter then PEA likely won't connect to that big incomer without lower rated fuses or MCB in front.

[RichCor]

Is this a new PEA/MEA install?

Crossy has stated in the past,

Posted 2013-06-03 11:36:25

The 'code' such as it is requires front-end RCD protection and 3-pin outlets on all new installations.

This is widely ignored but MEA/PEA may not certify and connect if it's not done.

[Crossy]

Indeed ^^^.

I would be hoping our OP has already decided to go with individual RCBOs on important circuits (like the water heaters), 3-phase RCBOs are not cheap.

We don't have a front end RCD but there is an RCD in each of the branch consumer units, Mr. PEA was more than happy with that.

[motdaeng]

many thanks for the use full reply.

schneider units has been out of stock at 6 diffrent shops! that is the reason we went for chang

(without any breaker inside). so we will not use the chang main breaker.

i prefer to have everything from schneider ...

have someone a picture or a diagramm the unit should look like?

we know 3 phase is expensive. all our nighbours have 3 phase

and we will go for it as well.

some add infos:

- our new house has 4 bedrooms, kitchen, dinning room, living room, 2 bathrooms, guest toilett,

2 storage room, 2 terraces, carport, bike room, tank room ...
- 2 air con 12'000 btu / 2 air con 9'000 btu
- 2 water heater shower about 4'500 - 6'000 watt
- 1 water heater kitchen about 6'000 watt
- 3 water pumps (for use water / drinking water / pond water for gardening)
- 1 oven kitchen / 1 fridge
- about 52 down lights (maybe with led) / about 10 garden lamps / 1 or 2 and some 3 way switch's
- every room has 1 to 3 plugs

thanks a lot

motdaeng_noththailand

[Crossy]

We have pretty much the same as that ^^^ plus 5HP of garden water pumps on a single phase 15/45 and the 50A incomer has never opened.

A lot depends upon what your local supply can manage, if others are using 3-phase you are right to do the same. Don't be tempted to get any 3-phase appliances (apart from maybe water heaters).

[Anthony5]

Indeed ^^^.

I would be hoping our OP has already decided to go with individual RCBOs on important circuits (like the water heaters), 3-phase RCBOs are not cheap.

We don't have a front end RCD but there is an RCD in each of the branch consumer units, Mr. PEA was more than happy with that.

Crossy, why would you recommend individual RCBO's on the water heater circuits? The water heater has normally ELCB built in.

I have already 3 RCBO's in my fuse box, that would mean I've to add another 4?

[Crossy]

That built in RCD does nothing to protect you from contact with the incoming supply.

So if, maybe, the incoming cable comes off and contacts something conductive that's not earthed (metallized shower hose maybe), you die!

Our water heaters all have RCDs, but they're all also protected by RCDs in the CU, but of course, it's up2u.

[Anthony5]

That built in RCD does nothing to protect you from contact with the incoming supply.

So if, maybe, the incoming cable comes off and contacts something conductive that's not earthed (metallized shower hose maybe), you die!

Our water heaters all have RCDs, but they're all also protected by RCDs in the CU, but of course, it's up2u.

I understand, but my water heaters have each their dedicated MCB, which of course is behind a RCBO. Why isn't this sufficient?

My water heaters are also not mounted in the shower, but are multi point heaters.

[Crossy]

If you have a front end RCBO, no issue.

As I noted in my post, 3-phase RCBO's are not cheap, if our OP was going to use the provided MCB then he would need either a front end unit, or RCBOs on the individual circuits.

[billphillips]

Do some research before splashing out on your proposed LED lights, power surges can easily destroy them. At around ฿200 upwards each, it can become an expensive and an annoyingly regular pastime.

[Gonsalviz]

The breaker looks like a Chinese copy of a Schneider unit just branded Chang by some Thai importer. These copies vary from dangerous to okay depending on what company in China made them. Only way to really tell is to dismantle the breaker but that's not a good idea. The 100 amp rating is very high for a domestic installation so may not trip under some fault conditions, or at all if it is a poor copy. I would just treat it as a main switch and use breakers of a known quality for your individual circuits so they provide the protection.

Not this brand but I have bought these cheap imports and one side is open all the time, off the shelf. Take a meter with you or have them check it before you buy.

[motdaeng]

first i have to apologise, even i got a lot of great answers, i am still not sure about a few things :

- everything is a new installation (wired till today about 70 %)

- we have 3 phase 15 /45 amp / earthing / 18 circuits (pumps, heaters, air, lights, plugs, outside etc)

- i like to use only schneider breakers

- i have no clue what main breaker (100 amp?) and or what front end RCO (RCCB?) i have to buy?

is the breaker in picture the right one (approx 3'700 thb) ? do i need some additional installation

if i use this schneider main breaker?

as always, thanks for your great help

[Crossy]

Firstly, PEA will likely not connect a 15/45 with a 100A incomer (they wouldn't authorise my 63A main breaker), so you need an EZC100H3050 (50A) or EZC100H3045 (45A) which may prove difficult to obtain (talk to your sparks).

You will need a 3-phase Safe-T-Cut unit http://www.safe-t-cut.com/en/products/specail-a-3phese.html OR individual RCBOs on particular circuits (water heaters, outdoor outlets and lighting etc.) which may prove cheaper.

Again talk to your sparks, but don't accept the typical "Thai electric is different, no need", you do need earth leakage protection on, as an absolute minimum, the wet rooms.

[Bcgardener]

Agree with Cross on the PEA connection. They can be fussy with main breaker ratings. I just had a meter put in at our new factory, 100kva transformer and 160 amp PEA fuses. Main breaker was a 200 amp frame size Schneider but adjustable 140 - 200. Took a lot of convincing to get them to connect to it. They wanted a non adjustable 150A breaker. I won out in the end though.