Help Me Wire My House

[canuckamuck]

I am renovating and expanding an older house. I will have to redo the wiring from scratch. Please note an example of current equipment.

I have attached a pic of the upper and lower floors, listing where and what the electrical items will be. I don't need advice on which plugs or lights to buy, what I do need help with is is what kind of wires, breakers, and safety cut off device to buy. In the pictures I forgot to include two shower water heaters.

Also: I will be running power from my house to a shed that will run power tools, including a welder. And also power to the father-in-laws house which has only two outlets and two lights.

I can run wires and hook up lights and switches, but I know nothing of the rest; but this place is out in the sticks and I will likely be working with a local electrician. I would prefer to have all the right stuff before we begin. And this info will also tell me how much I need to spend.

[Crossy]

Have a read here http://www.crossy.co.uk/wiring/ and come back with specific queries

What size meter is currently installed (5/15, 15/45)? What size supply is actually available at your location (talk to PEA).

Any aircon?

Water heaters may be an issue if only a small supply is available, could be worth investigating storage type heaters or maybe gas fired.

[canuckamuck]

Have a read here http://www.crossy.co.uk/wiring/ and come back with specific queries

What size meter is currently installed (5/15, 15/45)? What size supply is actually available at your location (talk to PEA).

Any aircon?

Water heaters may be an issue if only a small supply is available, could be worth investigating storage type heaters or maybe gas fired.

Ok I will make a list and get the answers, but it will be two weeks because I have no internet up there yet.

And I will read your link in the meantime. Thanks

[Crossy]

Does Edge or GPRS work up there?

[canuckamuck]

Does Edge or GPRS work up there?

Actually I think I can get broadband up there, I get a wifi signal when I use the laptop, but it is passworded. I am just not at the stage to hookup internet yet because the house is really ripped apart. I don't plan to move in until Christmas so I just go off the grid while I am up there. and will get a line hooked up a little later on. I will look into Edge or GPRS, If I can't get broadband.

[Crossy]

To get you started.

Outlet circuits:-

Upstairs.

Downstairs.

Kitchen.

All wired in 2.5mm² cable with a 20A breaker.

Lighting circuits:-

Upstairs.

Downstairs.

Wired in 1.5mm² cable with a 10A breaker.

Water heaters:-

Separate circuits for each, wire in 4mm² on 25A breakers (up to 5.5kW) or 6mm² on 32A breakers (up to 7kW) or 10mm² on 40A breakers (up to 8.8kW).

So you'll be needing a Consumer Unit (distribution board) with room for 10 breakers plus the incomer and RCD positions.

Watch your maximum demand (comes back to what supply is available).

Run a 6mm sub-main to the shed on a 32A breaker (check how much oomph your welder needs) and then have a small CU in the shed with local RCD protection.

[canuckamuck]

Thanks a lot you ave already given me enough to ballpark the cost.

I will get back to you in a couple of weeks.

Your link was useful too.

[canuckamuck]

I am back from the west and ready to get started on the electrical.

I had a conversation with a Canadian sparky and he suggested a little different arrangement. Here is what He said:

In Canada we limit the number of lights or plugins to 12 on any one circuit, it can be a combination of both but not more than 12. If you are wiring for a kitchen or high amperage draw, Air con, hot water heaters, stove etc you should run a heavier gauge wire usually a number 12 gauge, 14 gauge should work good for every thing else. Limit the number of high draw appliances on any one circuit or else the breaker will pop when in use just when you don't want it too. It's a good idea to split some lights/plugins on the same breaker so as to prevent overloading one circuit by having all plugins on it. Usually we put one room on one breaker.

Is that a good alternative, or is it important to have the lights on separate breakers than the plugins (outlets)?

Also what are the equivalent measures for 12 gauge, 14 gauge...

[Crossy]

12 AWG = 3.3mm², 14 AWG=2.08mm² so they're roughly equivalent to 4 and 2.5mm² respectively.

It must be noted that Canada uses 120V 60Hz and (I assume) the US system of 220V bi-phase for high power appliances (stove etc), this means that here in Thailand a device of the same wattage will use half the current and therefore can use thinner wire (except the stove).

There is absolutely no reason why you should not run lighting and outlets on one circuit, however your breaker must be sized to protect the smallest cable in that circuit. So if you want to use a 20A breaker then the entire circuit must be run in 2.5mm² whereas one can use 1.5mm² on lighting only circuits with a 10A or 15A breaker.

If you discount A/C, water heaters and the stove (which should have their own circuits anyway) there are very few appliances that pull more than an Amp (220W). Exceptions mostly live in the kitchen (kettle, toaster, microwave etc) so having a separate power circuit (or two if you have a big kitchen) for the kitchen is a good idea, but for the rest of the home a single outlet circuit for each floor is normally adequate.

Unless you have a very small house / shed then I would stick to the Thai method of having outlets and lighting separate if only to avoid confusing the local sparkies. A useful side-effect of wiring like this is that you are unlikely to lose all power to a room at once, so if you pop the power circuit breaker the lights don't go out.

If you have a workshop with lots of wood / metal working machinery it would be wise to run a sub-main to the workshop and have a local distribution board there, means you don't have to walk too far when you pop the breaker

It really is entirely up to you, I've designed my home electrics to be one power circuit per room, lights are split into upstairs and downstairs, outdoor lighting is on its own circuit. There are a couple of exceptions, the kitchen has two power circuits plus a third for the freezer on a separate RCBO to protect its supply and the two smaller bedrooms share one power circuit. To add further complexity we have a large UPS to run all the indoor lighting, the home theatre, IT kit and 'er indoors telly in the bedroom, those outlets are red in colour, a genset provides backup to everything except the A/C and water heaters.

NOTE. If your area is prone to flooding (seemingly most of Central Thailand) then put your distribution board upstairs and make sure you can completely isolate the downstairs electrics in the event that the wet comes in.

[canuckamuck]

Thanks Crossy, I think I am ready to run some wires. I will return when it is time to hook it all up.

[electau]

You should run an earth conductor to all points of utilisation , eg socket outlets, light fittings hotplate unit . HWs, airconditioners etc If possible use flat twin and earth enclosed cable.

Install RCD protection on all final sub circuits.

Minimum number of circuits, Lighting 2 x 10A, Socket outlets 2 x 20A all other equipment on their own circuit.

Minimum size of submains 4.0 sqmm.

Current rating of cable ( enclosed in conduit or duct ).

1.0 sqmm 10A, 1.5sqmm 16A, 2.5 sqmm 20A. 4.0sqmm 25A. 6.0 sqmm 32A.10sqmm 50A.

Unenclosed in free air ratings are.

1.0sqmm 16A, 1.5sqmm 20A 2.5sqmm 25A. 4sqmm 32A 6sqmm 40A 10sqmm 63A.

Voltage drop from the point of supply to any point of utilisation within the electrical installation should not exceed 5%.

With cable current ratings the enclosed ratings are to be preferred for residential installations.

　

[haveaniceday]

Best I continue this thread, with so much great stuff in it already from Electau and Crossy. Thanks guys by the way.

I have a few, possible concerns and questions. I am a bit clueless on this I admit.

The biggest meter we could get was 15(45)Amp 3 Phase running 4 X 50mm Alloy cables.

It is a small house by western standards, 4 bedrooms, 2 bathrooms, western kitchen.

I have been looking a little bit at Aircons, each bedroom with have air, and later I expect the lounge room to have some units installed, but not yet, so working on 4.

It appears that inverter systems are a bit more economical, but from what I have read, it appears a big bonus is as they are running constantly, you avoid the initial draw down. How do I know if I am at risk of getting brown outs at the initial draw down when the compressor kicks in? Currently in a rental with 5 Amp meter, when the 2nd AC kicks in, lights dim and if the shower is on (water pump and little hot water heater), my UPS will kick in and beep away and the fridge will make werriod noises for about 20 seconds, really good brown out material !!!! ( I have since bought UPS for the fridge and TV, trying to avoid them dying while my name is on the rental).

I just looked at a AC in my room, says it is 1100W, any idea what would be the initial draw down when the compressor kicks in when starting?

Next, much to my surprise, the little shower hot water heater is 6500 Watts.

In the house we are building, it will need 3 of these, --- 2X bathroom and 1 X kitchen.

I can put gas hot water in, do you think these electric hot water heaters will cause issues?

There are clearly going to be several circuits in the house,

Lastly, the builder wants to lay the insulation in the ceiling (3 inch chopped strand fiber stuff in silver bags) before the wiring is done, this sound arse about face to me, any comments? Any concerns rearing a metal framed roof, and silver lined insulation?

Lastly, I want each room to have 1 light, the water pump and some low wattage lights out side to come on during a power failure and a couple of independ plug sockets and security alarm . ( Water pump is fine to be manually switched over ).

I presume that a generator that automatically kicks in is going to be expensive. I have a little gen set, max rated out put 2.0kW, I am happy with that for the short term. What is the easiest way of running a big UPS that automatically switches on in a power failure, we get allot of them them here.

In general, the cost of this bloody house has grossly blown out....... but I am not trying to be pathetic with foundations, roofing, security and electrical. With electrical, I don't want to go overboard, but it must be as decent as I can get it with a little redundancy.

Also, does it cause any problem having 3 or 4 safety switches, I presume on different circuits, to help redundancy and trouble shooting easier, trying to find the

offending device?

Does the below mean, the hot water heaters are a non issue?

Crossy Said:

Thailand uses 3-phase 4-wire so you need four identical cables.<br style="font-size: 13px; line-height: 19px; background-color: rgb(250, 251, 252); ">Your installation will probably be mostly single-phase appliances, these are connected between the neutral (the fourth wire) and one or other of the phases.<br style="font-size: 13px; line-height: 19px; background-color: rgb(250, 251, 252); ">Assuming your '15 Amp' meter is a 15/45 3-phase supply it will be capable of providing nearly 30kW of power!

Sorry for the messy post, kind of thinking out loud, any help will be awesome.

We are going to pay for materials and pay per socket and switch and an agreed amount to put the circuit boards in, hoping to avoid cable and breakers being to small and all off 1 non earthed circuit.

[Kwasaki]

I find 15/45 supply OK and could have sometimes 3 out of 4 air-cons all going at the time.

1100 watts will draw 5amps

6500 watts shower !! 3 on at the same time whow !

Mines a 4500W as well as ELB on the shower there's a 30amp safety breaker switch before the 20amp MCB in the dist box.

Lastly, the builder wants to lay the insulation in the ceiling (3 inch chopped strand fiber stuff in silver bags) before the wiring is done, this sound arse about face to me, any comments?

Yes a bit back to front but as long as he maintain it's lay when installing the wiring.

Any concerns rearing a metal framed roof, and silver lined insulation?

No.

[haveaniceday]

This is a excellent thread very relevant to my questions as well FYI if you found this interesting.

Crossy: Proposed Home Wiring System comments pleasehttp://www.thaivisa.com/forum/topic/505905-proposed-home-wiring-system/

[electau]

I find 15/45 supply OK and could have sometimes 3 out of 4 air-cons all going at the time.

1100 watts will draw 5amps

6500 watts shower !! 3 on at the same time whow !

Mines a 4500W as well as ELB on the shower there's a 30amp safety breaker switch before the 20amp MCB in the dist box.

Lastly, the builder wants to lay the insulation in the ceiling (3 inch chopped strand fiber stuff in silver bags) before the wiring is done, this sound arse about face to me, any comments?

Yes a bit back to front but as long as he maintain it's lay when installing the wiring.

Any concerns rearing a metal framed roof, and silver lined insulation?

No.

Yes there is. You should not use metallic foil over electrical wiring the risk is that a fixing may penetrate a cable. You may also have to derate the current rating of cables because wiring is partly or completly enclosed in thermal insulation. Metallic foil must be earthed if you intend to use it.

One would advise against the use and use thermal fibreglass batts instead. of foil. Earth the steelwork.

[electau]

Best I continue this thread, with so much great stuff in it already from Electau and Crossy. Thanks guys by the way.

I have a few, possible concerns and questions. I am a bit clueless on this I admit.

The biggest meter we could get was 15(45)Amp 3 Phase running 4 X 50mm Alloy cables.

It is a small house by western standards, 4 bedrooms, 2 bathrooms, western kitchen.

I have been looking a little bit at Aircons, each bedroom with have air, and later I expect the lounge room to have some units installed, but not yet, so working on 4.

It appears that inverter systems are a bit more economical, but from what I have read, it appears a big bonus is as they are running constantly, you avoid the initial draw down. How do I know if I am at risk of getting brown outs at the initial draw down when the compressor kicks in? Currently in a rental with 5 Amp meter, when the 2nd AC kicks in, lights dim and if the shower is on (water pump and little hot water heater), my UPS will kick in and beep away and the fridge will make werriod noises for about 20 seconds, really good brown out material !!!! ( I have since bought UPS for the fridge and TV, trying to avoid them dying while my name is on the rental).

I just looked at a AC in my room, says it is 1100W, any idea what would be the initial draw down when the compressor kicks in when starting?

Next, much to my surprise, the little shower hot water heater is 6500 Watts.

In the house we are building, it will need 3 of these, --- 2X bathroom and 1 X kitchen.

I can put gas hot water in, do you think these electric hot water heaters will cause issues?

There are clearly going to be several circuits in the house,

Lastly, the builder wants to lay the insulation in the ceiling (3 inch chopped strand fiber stuff in silver bags) before the wiring is done, this sound arse about face to me, any comments? Any concerns rearing a metal framed roof, and silver lined insulation?

Lastly, I want each room to have 1 light, the water pump and some low wattage lights out side to come on during a power failure and a couple of independ plug sockets and security alarm . ( Water pump is fine to be manually switched over ).

I presume that a generator that automatically kicks in is going to be expensive. I have a little gen set, max rated out put 2.0kW, I am happy with that for the short term. What is the easiest way of running a big UPS that automatically switches on in a power failure, we get allot of them them here.

In general, the cost of this bloody house has grossly blown out....... but I am not trying to be pathetic with foundations, roofing, security and electrical. With electrical, I don't want to go overboard, but it must be as decent as I can get it with a little redundancy.

Also, does it cause any problem having 3 or 4 safety switches, I presume on different circuits, to help redundancy and trouble shooting easier, trying to find the

offending device?

Does the below mean, the hot water heaters are a non issue?

Crossy Said:

Thailand uses 3-phase 4-wire so you need four identical cables.<br style="font-size: 13px; line-height: 19px; background-color: rgb(250, 251, 252); ">Your installation will probably be mostly single-phase appliances, these are connected between the neutral (the fourth wire) and one or other of the phases.<br style="font-size: 13px; line-height: 19px; background-color: rgb(250, 251, 252); ">Assuming your '15 Amp' meter is a 15/45 3-phase supply it will be capable of providing nearly 30kW of power!

Sorry for the messy post, kind of thinking out loud, any help will be awesome.

We are going to pay for materials and pay per socket and switch and an agreed amount to put the circuit boards in, hoping to avoid cable and breakers being to small and all off 1 non earthed circuit.

15/45 amp meter 3 phase 4 wire supply with 4 x 50sqmm aluminium cables will be ample.

Balance load over 3 phases. 45A will be your max demand per phase.

One really needs to know the actual connected load to calculate max demand accurately.

ie. Number of lighting points, no of socket outlets, aircon size in amps (each) etc.

,

[haveaniceday]

Q.Any concerns rearing a metal framed roof, and silver lined insulation?

A. Yes there is. You should not use metallic foil over electrical wiring the risk is that a fixing may penetrate a cable. You may also have to derate the current rating of cables because wiring is partly or completly enclosed in thermal insulation. Metallic foil must be earthed if you intend to use it.<br style="font-size: 13px; line-height: 19px; background-color: rgb(250, 251, 252); ">One would advise against the use and use thermal fibreglass batts instead. of foil. Earth the steelwork.

The actual foil I was referring to are I believe fiberglass batts in foil bags, that are sold at Global / HomePro in rolls. One reason of using the bags, is for better insulation I have read, but mainly I am putting in high volume ventilation exhaust fans ( 1 fan at first ) into the attic to suck out the hot air in the heat of the day. Having loose fiberglass batts up there would eventually end up in the fan with the airflow I would imagine.

Realistically, I think the wiring will be done first, I presume it would be easy to have to 'loose' so that the insulation can be inserted in underneath the wiring, so the wires would be free to sit on top of the insulation. One would need holes in the insulation cut out above fittings like lights under the ceiling.

I never thought of earthing the foil, but makes allot sense, thanks.

[electau]

Fibreglass pink batts are available in plastic sleeves.Do not place insulation over recessed light fittings to prevent overheating and fire. cables should be over 50% of their length in insulation to be derated. Short lengths of cable do not require derating.

Edited November 28, 2011 by electau

[haveaniceday]

Thanks electau, excellent advice, Can you remember if the big chains like Global have them in plastic?

"cables should be over 50% of their length in insulation to be derated "

I presume this is a slight typo ( or brain thinking quicker than fingers typing, I presume you mean that cables in the ceiling with over 50% of their length covered in insulation, (insulation batts), should be derated, or have a larger diameter cable that can take the 'load' more easily.

[elliss]

really good info,

what about any tests that can be done before switch on .

continuity / insulation .

RIP. :jap:

[electau]

A cable with a route length of eg. 30metres, 20 metres of this in thermal insulation, partly or completly would require derating. ie. a protective device with a lower current rating. 20A to 16A for 2.5sqmm cable. Derating is based on the circuit carrying full rated current.

One should avoid running cables in thermal insulation, run above in free air above the thermal insulation itself.

Cables lain on thermal insulation are regarded as partly enclosed, the same as in conduit or duct. Cables within layers of thermal insulation are completely surrounded and must be further derated.

　

Testing of electrical installations before connection to supply.

1. Visual checks

2. Earthing tests.( Continuity tests). Main earth and all protective earthing conductors.

3. Insulation tests 500V DC with an insulation tester. L to E, N to E.

4. Correct circuit connections

5. Polarity tests. L to N and L to E.

6. Functional test of all RCDs using test button ( power connected).

[haveaniceday]

Gezz, I have 11 threads open on electrical in Thailand, all have some little golden gems of tips in them, no point making a new one.

With the house construction, it was pay for builder, we pay for materials. The things not included were electrical, pain and the piles in the foundations. Defiantly, the house is much stronger this way as we bought stronger materials and less short cuts have been taken.

With electrical, we have been banging our heads on a brick wall. Out of the 4 "electricians", two tried to convince us that we only need 2 cable and not earthed.

I am worried of them using cable that is to small which seems to be the norm here. I wanted to pay for materials and then pay them instillation per switch socket etc on top of a fixed price for distribution boxes etc. Just trying to eliminate reasons for cutting corners. So far all have refused.

I do want advice however, we have inbound from the street a 15(45) 3 phase, 4 cable.

I want to break it up into several circuits, I also see some of the reasoning of having several RCCB's (Safety Switches) to help and avoid a false trip knocking out the whole house, and to help to isolate that troublesome fault, when or if it shall occur. I also want to keep the outdoor lights separate to the house. (About 20 lights for security)

Would it be advisable to buy 3 separate 'distribution boxes', I use that term loosely, I am talking about the Safe T Cut boxes that have a main switch, a RCCB and about 6 circuit breakers in them.

Is that the easy way of doing it?

What about back up lighting, we live in a black hole at night, I want it so when we get many of the power failures, some lights come on automatically in each room.

I am happy for a little 3w compact florescent and also have some spread around out side. It would be good if these lights could last an hour. I presume it would be money well spent to get another Safe T Cut distribution box for this as well. How hard is it for a battery and switch to operate this? I would be happy to charge the battery once a week.

We are rural and have allot of power failures, I have a little 2Kwh (constant) petrol gen set that I would like to use as well. Would be nice to have a few outlets spread around the house, the water pump to be able to be 'transferred' over and the above 'emerg' lights to run off the gen set for prolonged outages.

Any ideas?

Useful resources worth noting that helped me:

http://www.3phasepower.org/

http://en.wikipedia.org/wiki/Three-phase_electric_power

[Crossy]

HND.

Have a look here for some ideas only intended as single-phase mind, we're not building a mansion.

There is no reason whatever why you should not treat your 3-phase installation as three separate single-phase supplies, it may make it easier to understand and wire up. Just make sure you balance your load between the three, don't worry about lights, but watch for big current items like water heaters and A/Cs.

For your lighting why not run all your internal lights of a decent sized UPS like we are, means the lights in use stay on when the power goes off.

This is our little 2kVA genny, keeps us sane whilst the power is off due to flooding

At night when the genset is off we have this UPS system, keeps a fan going all night, allows us to use the lights and the telly.

The UPS itself

and its box for those who want one

[haveaniceday]

Crossy : "There is no reason whatever why you should not treat your 3-phase installation as three separate single-phase supplies, it may make it easier to understand and wire up. Just make sure you balance your load between the three, don't worry about lights, but watch for big current items like water heaters and A/Cs."

Thanks for your help. I doubt I will actually have anything requiring 3 Phase, the air con says Phase1 50hz. I can see the idea that at looking at a picture of a sine wave, that 3 phase is smooth. I am imagining a motor actually increasing and decreasing constantly on a single phase in the peaks and troughs, even though I can not hear it change or see any difference. I presume that it is this that people refer to as hard on the motors?

I presume in my home, even though little motors in the air con, water pump etc will run better on 3 phase, in the big picture the difference is negligible? Will my air con with Phase 1 written on it even run better on 3 Phase?

I am not into electrics, but I don't like locals telling me I am stupid for not wanting to install 2 prong plugs into my house and no earthing rods. I am glad for this forum, I have learnt allot from the sparkies here.

I am 99% going to break up the 15 (45)A 4cable 3Phase into 3 single phase circuits. I like the idea of 3 indipenant consumer units, each with a safety switch and breakers. Seems to be a direct correlation with in laws visits and the safety switch doing it's job and flipping off. Dave, you could not even believe some of the shit they have done with out seeing it with your own eyes. But, Can you confirm that if I don't do 3 indepentant circuits, and put in 3 phase, that all the "woomfff" from the 3 inbound Live cable would be combined into one consumer unit and things like brown outs of lights dimming would be less likely than 3 X 15amp cuicuits as there is less likely going to wasted capacity when motors initially kick in etc? I would imagine that much less cable would be required for this 3 phase system or is it so close, it doesn't really come into it for a residential house?

In the quote above, you say make sure to balance the load. Are you referring to just be smart and average out the loads so non of the 3 X single phase un fairly carries the burdon and is over loaded. eg, look at the watts and spread them out across 3 consumer units, each connected to 1 live.

eg, each of the 3 little hot water heaters on different consumer boxes, air cons spread out etc, thought gone into wiring the kitchen, spot lights etc, so if they are all on at once, they would have a similar load.

I presume the balance the load between the 3 is to do with my interperation above, and not so much below ?

"If the supply neutral of a three-phase system with line-to-neutral connected loads is broken, the voltage balance on the loads will no longer be maintained. The neutral point will tend to drift toward the most heavily loaded phase, causing undervoltage conditions on that phase and overvoltage on a lightly loaded phase; the lightly loaded phases may approach the line-to-line voltage, which exceeds the line-to-neutral voltage by a factor of √3, causing overheating and failure of many types of loads." http://en.wikipedia.org/wiki/Three-phase_electric_power Single-Phase -Loads paragraph.

Edited December 11, 2011 by Crossy
added 'not' to paragraph 3 at posters request :)

[haveaniceday]

Also,

I am not that keen to run the house on a big UPS, just planning to use little computer ones, but do want some emergency lighting and possibly a bugular alarm on it as well. At this stage, I am choosing between about 8 of those little boxes with two little lights on the top that look like ears, for about 1600b each that are plugged in and come on when the power fails.

I actually like the idea of a separate 12V cuicuit and just have a 12v countersunk light in each room and many outside connected to a 12v battery, and then a switch connected to a the mains and if there is a cut these come on. Is this idea practical? I would just top up the battery once a week.

Edited December 9, 2011 by haveaniceday

[Crossy]

HND.

What you say in Post #24 is pretty much on the money. With single-phase appliances having a 3-phase incoming supply makes no odds to the appliances, just lets you have 3 times as many on the same meter size.

You can't just join the three phases together, that would result in a BIG bang, so you have to arrange for three single phase boards or a 3-phase board wired with only single phase circuits, it won't use any more cable.

Those 'Rabbit Ear' emergency lights are pug ugly and would not get house room in our home.

I thought of having a few low voltage lights around, but remember you have to wire them, using a central UPS means no extra wiring other than in the distribution board and the same switches work the same lights.

If you do go for the 12V option use a standby charger to keep the battery topped up so it's there when you need it.

[haveaniceday]

I can't find the post right now, but a previous poster in a lost thread, refereed to a "full house surge protector" which just looked like a big CB put before the distrubtion board. He said it cost about 2000b.

When dividing the 3 phase supply into 3 X single phase supplies, I presume I need 3 of these correct?

I am also looking very seriously at a UPS like Crossy's, but not to run the house. To run, alarm systems, maybe computers, but mainly for security. There are no other lights near the house, I want it to run a seperate circuit to come on when there is a power failure. Maybe have a photo switch so he area lights up like a Xmass tree with a black out at night form the UPS, also each room in the house will have a small light.

Can I get a switch easily to make a cuircut live, I imagine the power comming form a mains socket to keep the switch open, then when there is no power the switch closes and opens up power tot hat circuit form the UPS supply.

[Crossy]

When dividing the 3 phase supply into 3 X single phase supplies, I presume I need 3 of these correct?

Yes, although there are 3-phase versions available, 3 x single phase will do the job just as well.

Can I get a switch easily to make a cuircut live, I imagine the power comming form a mains socket to keep the switch open, then when there is no power the switch closes and opens up power tot hat circuit form the UPS supply.

Yes, easy to do. You can get relays with 220V AC coils and change-over contacts. Your circuit MUST switch both live and neutral and it would be wise to protect the incoming circuits with quick-blow fuses just in case a relay contact gets stuck.

You could use contactors which are designed not to stick but these are considerably more expensive than the relays would be and in a low current lighting application I would use the simple and cheap option.

[janverbeem]

HND.

Have a look here for some ideas http://www.thaivisa....-wiring-system/ only intended as single-phase mind, we're not building a mansion.

There is no reason whatever why you should not treat your 3-phase installation as three separate single-phase supplies, it may make it easier to understand and wire up. Just make sure you balance your load between the three, don't worry about lights, but watch for big current items like water heaters and A/Cs.

For your lighting why not run all your internal lights of a decent sized UPS like we are, means the lights in use stay on when the power goes off.

This is our little 2kVA genny, keeps us sane whilst the power is off due to flooding

At night when the genset is off we have this UPS system, keeps a fan going all night, allows us to use the lights and the telly.

The UPS itself

and its box for those who want one

Crossy,what are the specs and price of the batteries attached and how long would the ups work with say a load of 1000 Watt.As I can't see it on the box,does this ups function as online or line interactive.

[Crossy]

Crossy,what are the specs and price of the batteries attached and how long would the ups work with say a load of 1000 Watt.As I can't see it on the box,does this ups function as online or line interactive.

UPS is a simple off-line unit, direct feed through of mains input until the power goes off then switch over to battery.

The batteries are Yuasa NPX-150R 12V 40AH sealed lead-acid. Cost about 3 k Baht each, you may get similar capacity car batteries for less but watch your ventilation when these are charging.

At 1000W (about 85A at 12V) those batteries should last about 2 hours, at high discharge rates the battery capacity is reduced.