Which Consumer Unit Should I Buy?

[Monkeypants]

I am currently building a 3 bedroom bungalow.

It will have 3 air con units, 2 showers, Electric Oven (bought already) and other regular appliances that you would have in your household, including desk top PC.

Which consumer unit should I buy, I have seen a few and they vary in size,length.

Also do Thailand have 3 core cable now?

Is 2.5 mm cable good for all lighting and sockets?

I assume aircon cable will need to be bigger?

Is the oven ok on 2,5mm cable?

I have viewed crossys wiring site, and I am totally lost with it, I am very scared of electric, really I am. And this seems to block my learning ability.

I have to put my faith in a Thai electrician, but I thought that if I buy the right equipment, he may know what is required.

I will have to start buying the cable and consumer unit soon.

[Monkeypants]

Also how do you join two wires together safely, In the uk we would use a junction box, here a bit of tape seems to do the job, I was thinking block connectors?

And I have seen some electrics installed where you will have a wall switch for the lights and a socket placed further down the wall for plugs with the feed coming from the light switch, to the socket is this acceptable?

I think I understand Crossys electrical diagram where he says 7 outlets for one feed so I was thinking that you would have several feeds from the consumer unit , several feeds for sockets and several feeds for lighting 3 core cable going back to the consumer unit.

In the UK I have also seen little fuse thingies, like a light switch but instead of a switch it holds a 13A fuse, do I need to get something like this installed also?

[Rimmer]

If you have a three phase supply you will need a TP board, you use the word consumer unit and this would imply a single phase supply. I prefer a metal consumer case unit because they have mechanical or impact protection.

2.5mm cable is suitable for a 30a ring main system, ask your electrician if he is familier with the system as this is far superior and less costly than stringing wires all over the place. I have not seen three core cable but that is not to say you can't buy it. Usually the ring would be 2 core and earth. If you cant find 2c + E run a separate earth wire and use ordinary twin PVC sheath PVC insulated.

1.5 mm is the size for lighting circuits. If the conductors are too big they are very difficult to work with and get in the terminals.

Thai electricians like to over engineer every cable size and breaker because they do not know how to size the cables correctly. The net result is that is costs you a lot more to buy cable.

You will need to post the rating of the oven and air cons so someone can give you the correct cable and breaker sizes.

I am sure Crossy will be able to give you advice in plain English that you can easily understand if you get stuck.

Edited January 17, 2009 by Rimmer

[Crossy]

I am currently building a 3 bedroom bungalow.

It will have 3 air con units, 2 showers, Electric Oven (bought already) and other regular appliances that you would have in your household, including desk top PC.

Which consumer unit should I buy, I have seen a few and they vary in size,length. You should get one which will give you several spare positions, I would advise the use of a split-service CU like this one http://www.tlc-direct.co.uk/Products/CPS148P.html

Also do Thailand have 3 core cable now? Not easy to get, use regular twin with a separate ground wire

Is 2.5 mm cable good for all lighting and sockets? Use 2.5² with a 20A breaker for the outlets and 1.5² with a 15A breaker for the lights

I assume aircon cable will need to be bigger? Wire your aircon with 4mm² with a 25A breaker but verify the cable if you have a particularly big unit.

Is the oven ok on 2,5mm cable? Check the oven rating, over about 15A you should use 4mm², the oven should have its own breaker. You will need separate breakers for the water heaters (we need to know the ratings to define the cable).

I am assuming you will have a 15/45 single-phase supply for which you will need a 63A incoming breaker with 16mm² cable from the meter on the pole.

If you show your Thai sparks the drawings on my website, particularly the split-service CU he will hopefully understand

Cable and breaker sizes here http://www.crossy.co.uk/wiring/Circuit%20types.html

Edited January 17, 2009 by Crossy

[Monkeypants]

thanks crossy.

I know i am going to be a pain in peoples sides as things progress, this is through pure lack of knowledge, I hope you understand that my need in yours, and others expertise will be crutial to me and my families safety, , as i said earlier I am scared shitless, with electrics and of course Somchai the electrician, who generally grow rice for a living, not patronising here, just a fact.

So firstly I have a 3 phase chicken farm, and no means of tapping into any other existing supply as yet.

Does this create a problem ?

Edited January 17, 2009 by Monkeypants

[Somtham]

I am assuming you will have a 15/45 single-phase supply for which you will need a 63A incoming breaker with 16mm² cable from the meter on the pole.

Cable and breaker sizes here http://www.crossy.co.uk/wiring/Circuit%20types.html

Crossy - sorry if you've answered this question already but....when you refer to wire size are you referring to copper or aluminum? And if copper is there a coefficient that can be used to calculate the aluminum size?

rgds

[Crossy]

So firstly I have a 3 phase chicken farm, and no means of tapping into any other existing supply as yet.

Does this create a problem ?

No problem, but it may cause a rethink of how we supply your house, I assume you want to tap off the existing supply to power your bungalow.

Have a look at the 3-phase meter and tell us the size 5/15, 15/30, 45/100 and the rating of the incoming breakers or fuses.

[Crossy]

Crossy - sorry if you've answered this question already but....when you refer to wire size are you referring to copper or aluminum? And if copper is there a coefficient that can be used to calculate the aluminum size?

All sizes are copper. Unless cost is a serious consideration I'd avoid aluminium as the connections can become unreliable if not made correctly (i.e. by Somchai electrics inc.), certainly only consider aluminium for the incoming cables.

I'll dig out the adjustment factor for Ali, but generally you use one size bigger, so your 16mm² copper meter tails become 25mm² in Ali.

Edited January 17, 2009 by Crossy

[citizen33]

Crossy's site and advice are invaluable. I've also found that the conventional 2.5 twin plus earth (UK style) is hard to get but did find a similar product with three 2.5mm cores with sleeves in the correct colours (i.e. the earth is also insulated). This is what I have used with a house and two bungalows I did myself a while ago: bought some in China Town and then found that Global House sometimes sells this too. Of course, a separate earth cable will work fine and I've used this with 4mm twin. But what I've found is that the rodents really like the stuff I bought and ate much of the green insulation. After seeing what has happened with rodent nibbling cables in the ceiling space, I've tried in recent projects to encase all cables in conduit. My experience has been that the mice still nibble through the grey/green round electrical conduit, but find the blue water pipes a bit harder. So my theory is that this would work well as a cheap conduit and I notice that some Thai electricians use this.

Edited January 17, 2009 by citizen33

[dotcom]

Crossy. Your breaker box. Is that for sale in Thailand? or will he need to go with Square D?

2.5 x 2 + 1.5 x 1 is easy to find. Just locate the biggest electrical supply store in your town. I they don't stock it they can get it. remember it's for sockets only.

Agree 4 mm for cook stove & oven.

Run 6 mm for air cons & water heaters to be safe. Crossy is right we need to know wattage to suggest breaker values.

Don't use aluminium for anything. Use copper ONLY.

Aluminium has been outlawed in the states for 30 years.

For cross country runs it's fine.

[Somtham]

Crossy - sorry if you've answered this question already but....when you refer to wire size are you referring to copper or aluminum? And if copper is there a coefficient that can be used to calculate the aluminum size?

All sizes are copper. Unless cost is a serious consideration I'd avoid aluminium as the connections can become unreliable if not made correctly (i.e. by Somchai electrics inc.), certainly only consider aluminium for the incoming cables.

I'll dig out the adjustment factor for Ali, but generally you use one size bigger, so your 16mm² copper meter tails become 25mm² in Ali.

Thanks Crossy. Most of the houses around us use aluminum for the feed from the meter to the house with interior wiring being copper.

rgds

[Monkeypants]

ok thanks so far.

I will get the wattage and the info on the 3 phase supply.

thanks fella's

[Crossy]

Crossy. Your breaker box. Is that for sale in Thailand? or will he need to go with Square D?

Dunno, it was just a convenient link to a split-service unit, Square-D will do a similar unit

[Crossy]

Crossy. Your breaker box. Is that for sale in Thailand? or will he need to go with Square D?

Dunno, it was just a convenient link to a split-service unit, Square-D will do a similar unit

If a split-service unit is not available, just get the biggest you can find. It is easy to modify for split-service by taking your hacksaw to the neutral bar Alternatively, two smaller units can be wired as a split-service system.

Edited January 18, 2009 by Crossy

[Monkeypants]

OK Managed to find out so far that the 3 phase supply is 100kva?

and we have 30 amp breakers in the farm.

[Crossy]

OK Managed to find out so far that the 3 phase supply is 100kva?

and we have 30 amp breakers in the farm.

Hmmm, you need to have a look at the meter. It should have something like 5/15, 15/30 or 30/100 on the faceplate. This is the 'size' of the supply that PEA are providing.

If you have a 100kVA transformer there is likely plenty of oomph available for the house as well but you will likely need to upgrade the meter and possibly the incoming cables. Does the transformer supply other properties or is it 'yours'?

Are the 30A breakers the main incoming breakers?

Alternatively you could get a single-phase 15/45 meter installed by PEA that feeds the house alone (supplied by the same transformer), it may be advantagous to have the house billed separate from the farm.

[Monkeypants]

OK,

Thanks again, I will be a little more thorough and post back ASAP.

[Crossy]

Thanks again, I will be a little more thorough and post back ASAP.

No problem

You may wish to take photos of everything that looks remotely relevant, good closeups so we can see ratings etc. Easier than trying to describe what we need to look for

[Monkeypants]

Here is a pic of the 3 phase metre, we have 5 farms and this metre comes directly from the the big 3 phase supply, we have 4 other metres for each farm, Below the metre is a 100 amp breaker and below that are 3 60 amp breakers.

[Monkeypants]

Also this may be a temporary supply to the house from here,but that would depend on our local PEA. Currently the electric poles supplying the electric are located on someone elses land, they want us to re route the existing supply as to not to cross their land, so simply just adding a few wires to the existing poles are out of the question at the minute. I agree that the cost per unit by tapping into our existing 3 phase supply will cost more to run, and eventually we will have a seperate supply, this may take months, even years. So at the minute I am stuck.

[Crossy]

Hmmm, scary, I expect most of the sparkies on this board are thinking the same

"Safe" is not a word I'd use for that panel, does it have a cover, I thought not. If the incomer and 1-phase breakers had the touch covers fitted (like the 60A 3-phase breaker) the danger would be significantly reduced.

Whatever, that is a 100A incomer so unless your house is a mansion you could add another 60A 1-phase breaker (like the 2 on the right) run off the leftmost phase (that does not already have one) and the neutral (that's the wire that does not pass through the big 100A switch). This would be about the equivalent of a 15/45 supply.

Link to your house with 16mm² cable, check the distance if more than about 40-50m you should use 25mm².

Obviously you then have a consumer unit in the house with an RCD etc, do not however install a MEN link in this CU, just have a local earth stake.

PEA MAY add a single-phase 15/45 meter for your house off the same supply (taken on the hot side of the existing meter) which would give you seperate metering. This would be subject to the incoming cables being sufficient to handle the additional load, they will advise.

You may want to borrow a clamp-meter and check the current being pulled from each phase to get an idea how close to the line your supply is

Edited January 27, 2009 by Crossy

[Crossy]

Missed the edit window

You should really use a Henley block to link those neutrals, better than shoving multiple wires into connectors. Looks like this:-

[Artisi]

Here is a pic of the 3 phase metre, we have 5 farms and this metre comes directly from the the big 3 phase supply, we have 4 other metres for each farm, Below the metre is a 100 amp breaker and below that are 3 60 amp breakers.

I'm not a sparkie - but it looks <deleted> scary to me.

[dotcom]

Monkeypants. Have PEA give you a quotation to move the poles or add new ones as necessary.

[Monkeypants]

Not yet, we are in the process of talking with them, also our" Orbator"

No decesion as yet.

Cheers