Electrics for new house - can it be explained in layman's terms?

[Sophon]

Unfortunately there is no room for bigger conduits, I can barely fit in the ½" conduits.

So what about 3 x 1.5 mm (light plus ground) and 2 x 2.5 mm (outlets), will that fit into a ½" conduit? If it helps, the wires for the outlets will only be running for approximately 6 meters, after that only the light wires will be left.

Thanks for the replies.

Sophon

[Crossy]

Like I said you will get it in with a wrestle, if there are no / few bends you'll be OK with your original idea, give it a try.

Do look at mini-trunking, the square section allows more cables in the same space.

[Sophon]

I say 3 wires is the maximum to run through 1/2" conduit < 2.5mm2. There's probably some code for that but I think close enough. For wiring a house, you want single core, double core, etc. along with a plan. The plan will determine how much you need for whatever. Plan it.

I am getting slightly confused here. You say maximum 3 wires, but Crossy says that 7 might fit albeit with a bit of a squeeze. Are you talking about 3 double core wires, so the equivalent of 6 single core wires?

Sophon

[Crossy]

No codes here, you'll be over 60% fill factor so would not be to code in the US.

You will certainly need to pull all the wires at once (one of the reasons for limiting fill factor is to ensure you can get another wire in), in reality, try it, if you can't get all in use Plan B.

[bankruatsteve]

Why would you need to run wires for lights and outlets through the same conduit? Whatever - just seems a bit strange to me.

[Crossy]

Space steve

There is also no reason why our OP should not power lights from the same circuit as the outlets (standard practice in some countries, including Thailand) meaning he'll only need three wires. In this case all the wiring must be sized to suit the breaker in use. 2.5mm² on a 20A breaker or 1.5mm² on a 15A breaker.

If the outlets in question are small power only (not the kitchen or your welder), 1.5mm² and a 15A breaker will be quite adequate.

[Sophon]

Space steve

There is also no reason why our OP should not power lights from the same circuit as the outlets (standard practice in some countries, including Thailand) meaning he'll only need three wires. In this case all the wiring must be sized to suit the breaker in use. 2.5mm² on a 20A breaker or 1.5mm² on a 15A breaker.

If the outlets in question are small power only (not the kitchen or your welder), 1.5mm² and a 15A breaker will be quite adequate.

That's an interesting idea. I guess the downside to that solution is that if a circuit develops a fault I won't know if it's a problem with a lighting or a power circuit.

It's not like there will be a heavy load on the downstairs circuits, we are only talking about 5 inside lights, 5 outside light and 4 power outlets. And the only thing constantly connected to the power outlets will be the water pump and washing machines, and otherwise it will only be equipment like TV, laptop and vacuum cleaner that will occasionally draw power down there. I think I will follow this suggestion, but just to be safe (you never know what you will connect in the future) I will go with 2.5 mm² wires.

I bought a Schneider/Square D distribution box yesterday with room for 14 breakers. Now having a few spots for breakers in reserve I am thinking about splitting up the lighting circuits for the main living area onto two separate breakers and maybe do the same for the power circuits. That way, if if some circuit develops a fault that trips the RCBO I can switch off that circuit and still have lights/power in some rooms. Any thoughts on advantages/disadvantages with this approach?

Thanks again to all for your helpful suggestions.

Sophon

[thaibeachlovers]

If cost is a factor, IMO there is no point in running 3 core cable and putting in 3 pin outlets everywhere when almost every appliance you own will only have 2 pin plugs.

I have just finished rewiring 2 houses, and I only grounded the plugs that needed it eg computer outlets, AC and water heaters etc.

Of course, I have an RCD installed on both houses..

If you have trouble finding the correct length ground rods ( Home Pro didn't have them when I needed some ), Global House does stock them.

[Sophon]

If cost is a factor, IMO there is no point in running 3 core cable and putting in 3 pin outlets everywhere when almost every appliance you own will only have 2 pin plugs.

I have just finished rewiring 2 houses, and I only grounded the plugs that needed it eg computer outlets, AC and water heaters etc.

Of course, I have an RCD installed on both houses..

If you have trouble finding the correct length ground rods ( Home Pro didn't have them when I needed some ), Global House does stock them.

Obviously, cost is a factor to a certain degree for everyone. But as I see it the savings by not grounding all the outlets are comparatively minimal, so we might as well ground them all. There might come a day when you move things around, so what used to be a bedroom is now an office, and if so having the outlets grounded comes in handy. I will make one exception though, we will not have outlets in the bathrooms, so I will have a standard, ungrounded outlet in the switch box outside the bathrooms so we can use an electric toothbrush or a hair dryer should we want to one day. The outlet will be ungrounded because the box won't accommodate two switches plus a grounded outlet.

We don't have a Home Pro here in Lamphun, so we shop mostly at Global and I have seen two meter ground rods there. There are two different types at vastly different prices. From memory the cheaper one costs considerably less than 1,000 Baht while the price for the more expensive one is at around or in excess of 3,000 Baht. I assume that the expensive one is solid copper, wile the cheaper one is only coated in copper. I am thinking that the cost for the solid copper one is worth the extra cost, but if it makes little difference I would obviously want to save my money.

Sophon

[thaibeachlovers]

If cost is a factor, IMO there is no point in running 3 core cable and putting in 3 pin outlets everywhere when almost every appliance you own will only have 2 pin plugs.

I have just finished rewiring 2 houses, and I only grounded the plugs that needed it eg computer outlets, AC and water heaters etc.

Of course, I have an RCD installed on both houses..

If you have trouble finding the correct length ground rods ( Home Pro didn't have them when I needed some ), Global House does stock them.

Obviously, cost is a factor to a certain degree for everyone. But as I see it the savings by not grounding all the outlets are comparatively minimal, so we might as well ground them all. There might come a day when you move things around, so what used to be a bedroom is now an office, and if so having the outlets grounded comes in handy. I will make one exception though, we will not have outlets in the bathrooms, so I will have a standard, ungrounded outlet in the switch box outside the bathrooms so we can use an electric toothbrush or a hair dryer should we want to one day. The outlet will be ungrounded because the box won't accommodate two switches plus a grounded outlet.

We don't have a Home Pro here in Lamphun, so we shop mostly at Global and I have seen two meter ground rods there. There are two different types at vastly different prices. From memory the cheaper one costs considerably less than 1,000 Baht while the price for the more expensive one is at around or in excess of 3,000 Baht. I assume that the expensive one is solid copper, wile the cheaper one is only coated in copper. I am thinking that the cost for the solid copper one is worth the extra cost, but if it makes little difference I would obviously want to save my money.

Sophon

I believe the correct length is 3 meters for a single rod or two shorter rods some distance part and wired together.

Anyway, if you do a search that was all discussed some time ago.

I have two 2 meter rods wired together and they are the copper coated variety.

The Thai electrician I hired to install my shower heater used a one foot rod which I replaced the next day . Now I do it all myself with advice from the experts on here.

[Crossy]

I believe the correct length is 3 meters for a single rod or two shorter rods some distance part and wired together.

Anyway, if you do a search that was all discussed some time ago.

I have two 2 meter rods wired together and they are the copper coated variety.

The Thai electrician I hired to install my shower heater used a one foot rod which I replaced the next day . Now I do it all myself with advice from the experts on here.

PEA specify a single ground rod of >2.4m.

Do be careful with multiple rods if you are in a lightning prone area, run the cable linking them outside the building. In the event of a local strike a LOT of current could flow down that cable due to differing ground potentials between the rods. I believe this is one the reasons multiple rods are outlawed in Australia.

[Sophon]

In addition to the distribution box we also bought a Schneider 45A RCBO. They had two models, one 45A and the other 63 A, and the salesperson said that since we will have a 15/45A meter, we would need the 45A model. That sounded logical enough, so we bought that model. Was that the correct choice, or should we have gone with the 63A model?

Sophon

[bankruatsteve]

The important thing is what your cable between the meter and the CU is rated and not exceed that. A 15/45 can safely deliver 63a (I think) but unless you plan on running a bunch of welders at the same time, you should be good at 45a.

[thaibeachlovers]

I believe the correct length is 3 meters for a single rod or two shorter rods some distance part and wired together.

Anyway, if you do a search that was all discussed some time ago.

I have two 2 meter rods wired together and they are the copper coated variety.

The Thai electrician I hired to install my shower heater used a one foot rod which I replaced the next day . Now I do it all myself with advice from the experts on here.

PEA specify a single ground rod of >2.4m.

Do be careful with multiple rods if you are in a lightning prone area, run the cable linking them outside the building. In the event of a local strike a LOT of current could flow down that cable due to differing ground potentials between the rods. I believe this is one the reasons multiple rods are outlawed in Australia.

Thanks for the warning Crossy.

Yes, the joining wire is outside the building and never had a local strike.

[IMHO]

The important thing is what your cable between the meter and the CU is rated and not exceed that. A 15/45 can safely deliver 63a (I think) but unless you plan on running a bunch of welders at the same time, you should be good at 45a.

I always thought that the two numbers on a meter rating were nominal/peak?

[Crossy]

The important thing is what your cable between the meter and the CU is rated and not exceed that. A 15/45 can safely deliver 63a (I think) but unless you plan on running a bunch of welders at the same time, you should be good at 45a.

I always thought that the two numbers on a meter rating were nominal/peak?

They are calibration and maximum.

But meters are very robust, a 100% overload won't kill them (although they lose accuracy). 63A is reasonable to fuse a 15/45, but see my note regarding our PEA inspector who insisted on a 50A incomer for our 15/45.

[Sophon]

The important thing is what your cable between the meter and the CU is rated and not exceed that. A 15/45 can safely deliver 63a (I think) but unless you plan on running a bunch of welders at the same time, you should be good at 45a.

I always thought that the two numbers on a meter rating were nominal/peak?

They are calibration and maximum.

But meters are very robust, a 100% overload won't kill them (although they lose accuracy). 63A is reasonable to fuse a 15/45, but see my note regarding our PEA inspector who insisted on a 50A incomer for our 15/45.

Sorry Crossy, I don't understand what you are saying. Should I stick with the 45A RCBO, or try to exchange it for the 63A model?

Any input on whether a solid copper ground rod is worth the extra money compared to the copper coated variety?

Sophon

,

[Jerry Cornelius]

Of course, I forgot (at least) one question.

Seventh question:

Any ball park suggestions as to what would be a fair price to pay for such a job (labour only, I will buy the materials myself)?

Sophon

With all these questions do you really think that you are qualified to purchase the correct materials ?

So long as he gets the right answers, why pay a commission and risk a contractor buying junk to improve their profit?

That's exactly the reasoning behind me buying materials myself.

I never said I was qualified to decide what is needed, but with the information I get here plus the advice given by our electrician it should be quite doable. It's basically just a question of buying myself what I have been recommended, rather than letting the electrician do it. That way there will be no financial incentive for the electrician to buy any particular brand or buy at a specific shop - or to pad the bill.

Sophon

Has any-one here posted their traceable (and current) accreditation?

Without doubt, there's some knowledgable folks who post here. However I would like to understand how you are able to disseminate the wheat from the chaff.

Particularly considering that different countries have differing requirements and standards.

Jerry

[IMHO]

Has any-one here posted their traceable (and current) accreditation?

Without doubt, there's some knowledgable folks who post here. However I would like to understand how you are able to disseminate the wheat from the chaff.

Particularly considering that different countries have differing requirements and standards.

Jerry

Have you ever asked your Thai electrician for their creds?

[Crossy]

Sorry Crossy, I don't understand what you are saying. Should I stick with the 45A RCBO, or try to exchange it for the 63A model?

Any input on whether a solid copper ground rod is worth the extra money compared to the copper coated variety?

The 45A unit will definitely get you past a PEA inspection, the 63A may not (as I discovered, see post #24). Our 50A incomer has never opened in two years despite use having 3 A/Cs and two 6kW water heaters, the diversity of never having everything active together saves us. With everything running we get about 80A, a C curve MCB will take between 40 and 400 seconds to open at 150% rated current, ours must be towards the longer time.

Get a decent quality coated rod and ensure the copper isn't damaged and all will be fine. You can use almost anything metallic for a ground rod (except Aluminium), hot dipped galvanised steel lasts well and is cheap, however PEA expect to see something copper coloured.

[Crossy]

Has any-one here posted their traceable (and current) accreditation?

Without doubt, there's some knowledgable folks who post here. However I would like to understand how you are able to disseminate the wheat from the chaff.

Particularly considering that different countries have differing requirements and standards.

Exactly what accreditation would be satisfactory? My Degree, Engineering Council or IEE (now called the IET) membership perhaps? None of which actually demonstrate any level of competence as an electrician (my EC membership is based around railway systems).

I'm not (and never have been) a member of NICEIC or any other 'accreditation' service, I stopped house bashing long before they were a twinkle in their father's eye and I'm not in O&G so no offshore certification.

There are enough qualified (and one or two currently practising) sparkies on this forum that poor or hazardous advice is quickly spotted and discredited.

Whilst you are correct, different countries have differing requirements (and quirks like the UK ring-final), basic electrical safety and good practice is the same the world over. A Brit, Aussie, American, Polish or Thai (the good ones are all earning pots in O&G) sparks would all come up with similar solutions.

[Sophon]

Sorry Crossy, I don't understand what you are saying. Should I stick with the 45A RCBO, or try to exchange it for the 63A model?

Any input on whether a solid copper ground rod is worth the extra money compared to the copper coated variety?

The 45A unit will definitely get you past a PEA inspection, the 63A may not (as I discovered, see post #24). Our 50A incomer has never opened in two years despite use having 3 A/Cs and two 6kW water heaters, the diversity of never having everything active together saves us. With everything running we get about 80A, a C curve MCB will take between 40 and 400 seconds to open at 150% rated current, ours must be towards the longer time.

Get a decent quality coated rod and ensure the copper isn't damaged and all will be fine. You can use almost anything metallic for a ground rod (except Aluminium), hot dipped galvanised steel lasts well and is cheap, however PEA expect to see something copper coloured.

Thanks Crossy. We went to the local PEA office today, and asked them what size of breaker we should have for a 15/45A meter, and the guy in charge said 63A. He thought a 45A breaker should be fine for two people and it probably will be, but it's always nice to have something in reserve should you one day need it. So we will go back to Home Pro tomorrow and try to exchange the RCBO for the 63A model.

If there is no nee for the solid copper ground rod, then we will go for the coated variety. It'¨s always nice to save some money, we have plenty of other stuff for the house to spend the savings on.

Thanks again.

Sophon

[Sophon]

We exchanged the 45A RCBO for the 63A model today at Home Pro, no problem at all.

As mentioned I think I want to split the lights and power in the living area onto separate breakers, so that we will always have some lights and power, even if one circuit should develop a fault that makes the RCBO trip. Would splitting along these lines make the installation problematic?

Anything you would do differently?

Also, we will start out using village water but might later want to switch to well water. I will prepare by running cable to the side of the house facing the well, but do anyone have any idea what size of cable is needed for a well pump? (I am guessing 2.5 mm², but it's just an uneducated guess). The well is quite shallow, even in the dry season the water table is less than two meters down.

Sophon

[Crossy]

I would have two power circuits to the kitchen. In a tropical home it's where all the power-hungry portable appliances live. Consider the microwave, kettle and toaster all on together, you'll be pushing a single circuit.

Also, be careful when your sparks wires the lounge lighting, two lives to a switch plate would be no issue back home but here you can guarantee that the neutrals from the lights will be all over the place (I know). Borrowed neutrals are not a hazard in normal use, but could catch an inexperienced sparks (or you changing a lamp) unawares with an unexpected shock.

Are you having a shed? Make sure you arrange its power.

For your water pump, how far from the house is the bore?

If you're running TV co-ax pull UTP (ethernet) cable at the same time for when you want smart TVs in the bedrooms.

Consider the point where your True and ethernet cables all land, you'll need some sort of wiring closet / cupboard to hide all those nasty cables along with the TV splitter / amp and network router. Oh and make sure the TV stuff arrives on the right side for the dish

[IMHO]

We exchanged the 45A RCBO for the 63A model today at Home Pro, no problem at all.

As mentioned I think I want to split the lights and power in the living area onto separate breakers, so that we will always have some lights and power, even if one circuit should develop a fault that makes the RCBO trip. Would splitting along these lines make the installation problematic?

Electrics - Breakers living room.jpg

Anything you would do differently?

Also, we will start out using village water but might later want to switch to well water. I will prepare by running cable to the side of the house facing the well, but do anyone have any idea what size of cable is needed for a well pump? (I am guessing 2.5 mm², but it's just an uneducated guess). The well is quite shallow, even in the dry season the water table is less than two meters down.

Sophon

Not the question you were asking, but those 8 down lights in the main living area are probably overkill - 6 would very likely do, unless you want it hospital bright? If the plan is indicative you'd also end up with a hot-spot where 4 of them are grouped together closely in the middle, and having 2 switches for the lights in a single area like that seems a little unintuitive to use.

[bankruatsteve]

FYI: If/when your main RCBO trips due to a fault on any circuit, ALL the circuits will then be dead. The separate MCB's are for overcurrent.

You could then turn off the MCB with the fault leaving the others live when you reset the RCBO.

Edited December 12, 2013 by bankruatsteve

[Sophon]

I would have two power circuits to the kitchen. In a tropical home it's where all the power-hungry portable appliances live. Consider the microwave, kettle and toaster all on together, you'll be pushing a single circuit.

Also, be careful when your sparks wires the lounge lighting, two lives to a switch plate would be no issue back home but here you can guarantee that the neutrals from the lights will be all over the place (I know). Borrowed neutrals are not a hazard in normal use, but could catch an inexperienced sparks (or you changing a lamp) unawares with an unexpected shock.

Are you having a shed? Make sure you arrange its power.

For your water pump, how far from the house is the bore?

If you're running TV co-ax pull UTP (ethernet) cable at the same time for when you want smart TVs in the bedrooms.

Consider the point where your True and ethernet cables all land, you'll need some sort of wiring closet / cupboard to hide all those nasty cables along with the TV splitter / amp and network router. Oh and make sure the TV stuff arrives on the right side for the dish

I will consider splitting the kitchen power into two circuits, but we really don't have/use that many appliances there. We will be cooking with gas, so we are talking about water heater, rice cooker and very occasionally the toaster or table top oven.

"Borrowed neutral" is when you (erroneously) use the neutral from another circuit to complete the circuit you are working on? I will stress to the electrician to use the neutral from the circuit he is working on, and will keep an eye on what he is doing.

No shed, but we have a room under the upstairs bathroom, where we will put the water tank/pump/filter. the room will have electricity.

Our well is approximately 20-30 meters from the house. But the water will have to be piped to the water tank, which would add another 20 meters. So 20-30 meters for the electricity and 40-50 meters for the water.

I don't see the point of smart TVs but will consider it anyway. I am not sure where to split the TV signal, it would be best to do in the attic and then lead the signal to the different bedrooms. What kind of signal amplification would I need?

Thank again, up early again I see.

Sophon

[Sophon]

We exchanged the 45A RCBO for the 63A model today at Home Pro, no problem at all.

As mentioned I think I want to split the lights and power in the living area onto separate breakers, so that we will always have some lights and power, even if one circuit should develop a fault that makes the RCBO trip. Would splitting along these lines make the installation problematic?

Electrics - Breakers living room.jpg

Anything you would do differently?

Also, we will start out using village water but might later want to switch to well water. I will prepare by running cable to the side of the house facing the well, but do anyone have any idea what size of cable is needed for a well pump? (I am guessing 2.5 mm², but it's just an uneducated guess). The well is quite shallow, even in the dry season the water table is less than two meters down.

Sophon

Not the question you were asking, but those 8 down lights in the main living area are probably overkill - 6 would very likely do, unless you want it hospital bright? If the plan is indicative you'd also end up with a hot-spot where 4 of them are grouped together closely in the middle, and having 2 switches for the lights in a single area like that seems a little unintuitive to use.

I agree with you about the 8 down lights, and I tried to change it to 6. But is turned out that there were no way to place 6 down lights and two normal lights in a harmonious way. Having only 6 down lights and placing the normal lights in the centre of the down lights will put the two normal lights too close together or the down lights too close to the walls.

We acutally have 4 switches for the living room area, two for the two groups of down lights and two for the normal lights. That gives us the flexibility to get the amount of light we want, and avoid it being "hospital bright". I expect we will be using the normal light the majority of the time, I am actually no fan of down lights. Each bedroom had 4 down lights in the original plan plus the centre normal light, but I replaced the down lights with a wall lamp to give a softer light.

Sophon

[Sophon]

FYI: If/when your main RCBO trips due to a fault on any circuit, ALL the circuits will then be dead. The separate MCB's are for overcurrent.

You could then turn off the MCB with the fault leaving the others live when you reset the RCBO.

As already mentioned I am a total newbie when it comes to electrics, but wouldn't the RCBO stop tripping, if I switch off the breaker for the faulty circuit? I realize that the RCBO tripping will cut all power, but the plan was then to switch off all circuits, turn the RCBO back on and switching on the breakers one by one. Once I figured out which circuit was faulty, I would just leave that one off.

Have I misunderstood something?

Sophon

[Crossy]

Nope Sophon, you're right, that's how it works, mostly.

A N-E fault on a switched-off circuit will sometimes trip the RCBO (and whether it trips will be dependant upon the load on other circuits) so you may also need to unplug appliances if you can't immediately nail which circuit is causing the issue.