Proposed Home Wiring System

[Crossy]

Being rather bored and unable to continue with our house construction due to 1.5m of water on the site (and now no access west of Highway 347) I put my mind to the electrical arrangements for our new submarine home.

As always multiple heads are better than one, so I welcome comments from those informed in these matters, as well as anyone else for that matter. Constructive criticism is welcome.

Conceptual diagram attached.

Visio-Breakers 1.pdf

The idea is to have 3 levels of supply protection:-

1. Non-Maintained (direct off mains), aircons, water heaters.
   
2. Backup (diesel genset), outlets, outdoor lighting.
   
3. UPS (4kVA UPS), indoor lighting, fans, specific power outlets (red) for Home Theatre, network kit and 'Er Indoors fish tanks.
   

It's no surprise given what I do for a living that this concept is based around the supply arrangements on a metro station.

A couple of thoughts:-

1. We may be able to get a 30/100 supply, if so the 63A incomer (which provides max-demand limiting) will be upgraded to 100A and the 30mA RCD in the GenSet panel will be replaced by a 63A/30mA RCBO to protect our 60A transfer switch from overload.
   
2. I'm not sure whether to put the water pump on the genset, it's currently on UPS (which should run it just fine).
   
3. The actual rating of the genset is currently undefined, depends upon available budget.
   
4. All circuits except the special freezer outlet and UPS supply are RCD protected.
   
5. The distribution boards, genset and UPS are all to be located on the upper level to protect from flooding.
   
6. No electrical equipment will be less than 1m from the downstairs floor level, again to keep out of all but the worst flooding.
   

Supply is TT so no MEN link.

The UPS will provide night time power so we don't need to run the genset and keep ourselves awake but can still access the loo, its current battery pack (6 x 12V 40AH sealed lead-acid) keeps the base demand going for a tested 6 hours, if space allows we'll increase the battery capacity.

Highway 347 at Chiang Rak Noi this morning 17/10/11

[InterestedObserver]

Novel concept, a UPS to power the night light so you can go to the loo. How can you overload a 60A transfer switch with only "outlets and outdoor lighting", even if including the 4kVA UPS.

[Crossy]

Novel concept, a UPS to power the night light so you can go to the loo. How can you overload a 60A transfer switch with only "outlets and outdoor lighting", even if including the 4kVA UPS.

As one gets older one appreciates being able to see to pee

We probably can't overload the transfer with normal use, but one can guarantee some bright spark plugging his unfused welder into one of our outlets, to be honest, having an RCBO is belt and braces.

[bankruatsteve]

Should be a showcase. But, what about your kitchen? Or, maybe you eat out? I like to put at least 2 circuits to the kitchen plus one more for the oven. Cheers.

[Crossy]

Should be a showcase. But, what about your kitchen? Or, maybe you eat out? I like to put at least 2 circuits to the kitchen plus one more for the oven. Cheers.

Duh, cheers Steve, I knew there was something fairly important missing (I expect 'Er Indoors might notice if nothing in the kitchen works), that's exactly the type of comment I'm hoping for. Or, have you found one of the 'deliberate' mistakes ?

I'll add the kitchen circuits to the Genset board, any generator we get will be quite capable of running the microwave OR the kettle (probably not both), oven if we have one can go on the Mains-only board

[electau]

Crossy, here are some suggestions that you may like to consider.

1. The main switchboard split into essential and non essential supply, if you have any distribution sub boards these will have to be split also. it means running two sets of sub mains to each board. However you may be able to dipense with the sub boards and run all circuits from the main switch board.

2. The manual 63amp transfer switch switches the essential load to the generator.

3. A 2 pole MCB installed on the main switch board marked " generator supply". Current rating to suit generator FL current.

4. Essential load. At least one 10A lighting circuit supplying essential areas. A minimum of two 20A power circuits for socket outlets for power in essential areas. the 20A circuit for the UPS, and a circuit for the water pump. If the pump is a small one it can be included on one of the essential power circuits.

5. The main switch will be a 63A 2 pole MCB that may be upgraded to 80A or 100A in the future.

6. Lighting circuits 10A.

7 Emergency lighting, from the UPS at present. Would suggest 230V LED lighting.

8. TT earthing system retained.

9. Any circuits on the ground floor to be segregated from the first floor and can be isolated from the main switch board.

10. RCDs on ALL socket outlets including the refrigerator and UPS.

11. Essential circuits clearly identified as such at the outlet.

12. During normal conditions the mains supply the non essential and essential loads, when on generator supply only the essential loads are supplied.

You have Crossy some of these already in your proposed electrical installation.

[Pacificperson]

How long do you want to be able to go without power? The set-up for 12 hours is very different than a set-up for 30 days.

Gas hot water and a gas stove will help out. Diesel generators last longer and require less frequent oil changes, but they cost a lot more. The larger your battery pack, the longer you can go without running your genset. It is nice to only run it when necessary. However, battery pack maintenance is a pain in the butt.

[Crossy]

@electau.

Agree mostly, we will have to agree to disagree in the RCD protection to the freezer and UPS input. It is vital that both these cannot be the subject of nuisance trips. UK regs permit unprotected supplies under certain circumstances, both these supplies will be UK legal

Lighting will all be LED except the outdoor floodlights which will be CFL, no point having 10A lighting circuits, with 5A I can use (cheaper) 1mm² cable if I wish (probably won't mind, 1.5 is much more robust).

UPS protected outlets will be red to identify them, that said the UPS is pretty robust, it will run the kettle and vacuum cleaner together (I've tested it) so it won't get fried if somebody does plug something odd in

Most gensets have an MCB to protect their outputs, so I don't see the necessity for another in the genset supply, transfer switch has an 'off' position to totally isolate the supply.

@Pacificperson.

The UPS is good for 6 hours or so at present but additional batteries will be installed to enable all night operation. Run the genset during the day to charge the batteries. Batteries are sealed lead-acid for low maintenance, I expect to have to replace them fairly regularly mind

I don't anticipate needing the genset very often, but with the current flooding situation I added one to the design, when it's needed I expect it to be running 12 hours each day.

I chose diesel as opposed to gasoline for fuel safety reasons due to the genset being on the upper level of the house (not indoors of course).

Cooking is gas anyway, hot water is not an issue, cold showers are bracing

[InterestedObserver]

However, battery pack maintenance is a pain in the butt.

If by maintenance you mean replacement cost, I agree. However, sealed deep cycle batteries require little maintenance other than keeping the terminals clean and well coated with Vaseline.

[Pacificperson]

However, battery pack maintenance is a pain in the butt.

If by maintenance you mean replacement cost, I agree. However, sealed deep cycle batteries require little maintenance other than keeping the terminals clean and well coated with Vaseline.

I lived 6 years in the tropics in a house that was 2 km from the nearest mains. It had solar and a 15KVA genset. It also had a large (tons) battery bank of 2V non-sealed wet cells. In my experience, the battery maintenance was a pain. Luckily, we got the batteries free, second hand, from the local tourist submarine. It would have been nice if they were sealed, but they would not have had the life span that these had.

Edited October 18, 2011 by Pacificperson

[bankruatsteve]

Hey Dave, looks like this should be a great post. Anyway... here's some thought's considering you are doing a new build:

RE your home theater: Think about the wires you might want for that: For example, I put speaker wires under the tiling for the surround sound speakers, routed wires for external speakers (ie: front/back), and routed coax (3 for the R/W/Y) from where my bedroom TV and Truevision feed is to my home theater in the living room. OK - I have to switch cables to go from one to the other but, so far, that's no problem. (I looked into coax switchers but WAY expensive). I know you can get an extra box but, in my case, I'm usually the only one to watch.

RE outside lighting: Or whatever you may plan for outside... I just retrofitted circuits for some garden lighting that I wish I had planned for initially. My suggestion would be to plan for at least 2 outside circuits (5/10 amp) for lighting that yoiu may not have the idea initially. Can't remember: did you have some outside receptacles in the plan? For sure you want to do that.

Cheers!

[T_Dog]

Crossy..... Very sorry to hear your build is affected by the flooding. Is the house site okay, or is the whole plot getting wet? Best to you on that as all of us greatly appreciate your insights on TV on sparky stuff.

Regarding inputs:

Nice to see your whole RCD protection, but why 30 mA unit protection when Square D sells 10 mA units individual breakers in Thailand that do not false trip? 30 mA is lethal in many cases so 10 mA is advised these days. I know the cost adds up this way but I like the isolation of problems with the individual breakers so this is what we plan on doing. I got shocked two years ago fairly severely when I was installing a burglar alarm so I am going with the 10 mA Square D units.

Other inputs: How about a dedicated 4 sq-mm line and breaker to the kitchen for an oven? Agree with the other post that the kitchen needs several outlets. You might not want an oven but if I want to buy your house, that would be nice!

Refrigerator and freezer outlets should not be RCD protected to ensure no false trips cause food spoilage.

For stereo wiring, we are using a fan conduit arrangement under the slab. Five conduits for speaker wires fan out from the stereo location and using a large size so we can run the burglar alarm wires there too with one conduit going to the secret room where the battery supply for the alarm and cameras resides.

Edit: Forgot to add: We are putting in a key operated "Away" switch that turns on the alarm system and also turns off the pump and possibly other non-essential stuff. Have not worked that out yet but that is a concept you might be interested in.

Edited October 18, 2011 by T_Dog

[electau]

Thanks for your comments Crossy, one was using AS3000. 10A MCBs and 1.0sqmm cable. 30mA RCDs.

Edited October 18, 2011 by electau

[Crossy]

Thanks for all the comments chaps, exactly what I wanted, as noted in my OP - multiple heads are better than one.

So, in the light of the comments received:-

1. Kitchen will have two outlet circuits plus a 4mm supply for oven and/or electric stovetop (futureproofing).
   
2. A single circuit for outside outlets protected by a 20A/10mA RCBO, outdoor outlets will be 1.5m from lowest floor level.
   
3. Lounge skirting (teak) will conceal trunking for data / HiFi cabling (no power in there).
   
4. We have a 4.5m wide patio door, a floor mounted UPS outlet and speaker terminal (for surround speakers) will be about 1/2 way across the door inside the lounge.
   

Keep the comments coming, I'll post an updated diagram when I've modified it.

[Sorridstroker]

As it is TT I would put the 40a submain on a 100ma rcd.

Unprotected sso on TT? - think you may require at least some sort of rcd protection to be compliant with BS7671 2008

You could drop it down to 500ma so long as you zs is below a certain value (value escapes me at the moment).

[Crossy]

As it is TT I would put the 40a submain on a 100ma rcd.

Unprotected sso on TT? - think you may require at least some sort of rcd protection to be compliant with BS7671 2008

You could drop it down to 500ma so long as you zs is below a certain value (value escapes me at the moment).

Thanks SS

Thailand has no domestic wiring standard, the actual best fit for the local conditions is AS3000 (Oz standard), but that does not permit TT so we need to mix and match a bit.

Taking a pragmatic approach, I still use the 16th Edition as a guide only 16th only requires RCD on outlets likely to be used for outdoor equipment. I could make it 17th compliant if I used a fixed appliance connector rather than an outlet (but I won't)

Submain will have RCD protection at the load end (small CU), the workshop is not separate from the main building so the run itself won't need RCD, just overload protection.

[Kwasaki]

Crossy my most important input, firstly build you land infill to 4metre high at least next year maybe worse.

Secondly go all gas supply, lights and heating no worries about electrocution.

Thirdly we get a fair amount of sunshine in Thailand so how about solar panels and a storage area for water heating some lights etc.

Edited October 19, 2011 by Kwasaki

[electau]

You would have to install an RCD on all final sub circuits as the fault loop impedance will be too high to operate an overcurrent protective device (MCB) on an earth fault within the required time (0.4secs).

Nuisance tripping can be minimised by reducing the standing leakage current by installing extra circuits to supply equipment that may be affected.

　

Edited October 20, 2011 by electau

[Crossy]

You would have to install an RCD on all final sub circuits as the fault loop impedance will be too high to operate an overcurrent protective device (MCB) on an earth fault within the required time (0.4secs).

Would replacing the incomer with a 63A/100mA RCBO do the trick if I can get the L-E loop impedance down to a few hundred ohms? Otherwise the fridge can have a 30mA RCBO to itself.

[electau]

You would have to install an RCD on all final sub circuits as the fault loop impedance will be too high to operate an overcurrent protective device (MCB) on an earth fault within the required time (0.4secs).

Would replacing the incomer with a 63A/100mA RCBO do the trick if I can get the L-E loop impedance down to a few hundred ohms? Otherwise the fridge can have a 30mA RCBO to itself.

One would advise you to put the fridge/freezer on its own dedicated circuit with a 20A 30mA RCBO.

[Crossy]

You would have to install an RCD on all final sub circuits as the fault loop impedance will be too high to operate an overcurrent protective device (MCB) on an earth fault within the required time (0.4secs).

Would replacing the incomer with a 63A/100mA RCBO do the trick if I can get the L-E loop impedance down to a few hundred ohms? Otherwise the fridge can have a 30mA RCBO to itself.

One would advise you to put the fridge/freezer on its own dedicated circuit with a 20A 30mA RCBO.

One would be tempted to agree, cheaper too

[T_Dog]

Crossy, Are you putting any lightning rods above the roof of the house with dedicated grounds? I never considered this back in the USA but the storms here can have much more lightning occurring. We are bringing in our power underground from the last pole so a major stroke has a place to go and will probably have at least one rod up above the roof. I have had a lot of experience with lightning mitigation and there is never a guarantee as it is so unpredictable.

[electau]

Crossy, Are you putting any lightning rods above the roof of the house with dedicated grounds? I never considered this back in the USA but the storms here can have much more lightning occurring. We are bringing in our power underground from the last pole so a major stroke has a place to go and will probably have at least one rod up above the roof. I have had a lot of experience with lightning mitigation and there is never a guarantee as it is so unpredictable.

Lightening protection /surge protection on the main switchboard is all that is required as primary protection. Lightening protection as you describe is not required on normal residential installations located close to ground level.

High rise buildings are a different matter altogether.

[bankruatsteve]

Just a thought for the entertainment center: I like to put 2 duplex/switched receptacles in a convenient place for that. ie: 4 plugs, 4 switches. For me that's: DVD, subwoofer, receiver, TV. Makes it easy to turn on/off when needed. Have both my living room and bed room.

[haveaniceday]

Crossy, your 2000w fully automatic Dc to AC inverter and battery charger, how much did it cost?

How much was the battery bank?

http://static.thaivi...38112_thumb.jpg

http://static.thaivi...38110_thumb.jpg

Edit: feel free to remove the link and insert the actual pic.

Edited December 9, 2011 by haveaniceday

[Crossy]

Crossy, your 2000w fully automatic Dc to AC inverter and battery charger, how much did it cost?

How much was the battery bank?

My 2000 Watt UPS was about 4500 Baht, batteries (12V 40AH) are about 3k each, in order to limit my expenditure I buy a battery every month or so, just keep adding and replace after a couple of years as they lose capacity (I use the warranty dates on the batteries).

I expect to have to replace all my batteries soon, we've had no power for nearly 2 months now due to the flooding and don't expect to have mains until January. We use our baby genset to charge during the day so we can have a fan and lights at night so the batteries are getting a rather hard life at present.

[janverbeem]

Crossy, your 2000w fully automatic Dc to AC inverter and battery charger, how much did it cost?

How much was the battery bank?

My 2000 Watt UPS was about 4500 Baht, batteries (12V 40AH) are about 3k each, in order to limit my expenditure I buy a battery every month or so, just keep adding and replace after a couple of years as they lose capacity (I use the warranty dates on the batteries).

I expect to have to replace all my batteries soon, we've had no power for nearly 2 months now due to the flooding and don't expect to have mains until January. We use our baby genset to charge during the day so we can have a fan and lights at night so the batteries are getting a rather hard life at present.

Crossy,I had a look at your inverter at Zeer the other day and they also have a 3000W at 8200 Baht.I wanted to order it right today and connect one 160 Ah deep cycle battery to it which would cost me 8000 Baht.Now I read that you buy a new battery every month,so that counts to a maintenance cost of 36000 Baht a year ,which I think is really over the top to maintain a ups system.Is this really neccesary?

I see you have 6 batteries connected,so that means that each battery lasts only 6 months?

[Crossy]

Crossy, your 2000w fully automatic Dc to AC inverter and battery charger, how much did it cost?

How much was the battery bank?

My 2000 Watt UPS was about 4500 Baht, batteries (12V 40AH) are about 3k each, in order to limit my expenditure I buy a battery every month or so, just keep adding and replace after a couple of years as they lose capacity (I use the warranty dates on the batteries).

I expect to have to replace all my batteries soon, we've had no power for nearly 2 months now due to the flooding and don't expect to have mains until January. We use our baby genset to charge during the day so we can have a fan and lights at night so the batteries are getting a rather hard life at present.

Crossy,I had a look at your inverter at Zeer the other day and they also have a 3000W at 8200 Baht.I wanted to order it right today and connect one 160 Ah deep cycle battery to it which would cost me 8000 Baht.Now I read that you buy a new battery every month,so that counts to a maintenance cost of 36000 Baht a year ,which I think is really over the top to maintain a ups system.Is this really neccesary?

I see you have 6 batteries connected,so that means that each battery lasts only 6 months?

Panic not!

Look at it as expansion rather than maintenance, I don't buy a battery every month or so because they fail, but because it's a way of increasing my capacity without a massive single outlay. I expect each to last a couple of years or longer depending upon how hard they are driven.

If your 160AH gives sufficient autonomy then there's no need to spend anything for a couple of years or until it loses sufficient capacity that your autonomy is no longer sufficient. I've actually not bought anything since the flooding as I don't relish lumping the things up 10 floors to our condo (the elevators are still not working). There's no more space in the rack anyway and the autonomy is still satisfactory. We now have temporary mains power so things are getting an easier life.

[janverbeem]

Crossy, your 2000w fully automatic Dc to AC inverter and battery charger, how much did it cost?

How much was the battery bank?

My 2000 Watt UPS was about 4500 Baht, batteries (12V 40AH) are about 3k each, in order to limit my expenditure I buy a battery every month or so, just keep adding and replace after a couple of years as they lose capacity (I use the warranty dates on the batteries).

I expect to have to replace all my batteries soon, we've had no power for nearly 2 months now due to the flooding and don't expect to have mains until January. We use our baby genset to charge during the day so we can have a fan and lights at night so the batteries are getting a rather hard life at present.

Crossy,I had a look at your inverter at Zeer the other day and they also have a 3000W at 8200 Baht.I wanted to order it right today and connect one 160 Ah deep cycle battery to it which would cost me 8000 Baht.Now I read that you buy a new battery every month,so that counts to a maintenance cost of 36000 Baht a year ,which I think is really over the top to maintain a ups system.Is this really neccesary?

I see you have 6 batteries connected,so that means that each battery lasts only 6 months?

Panic not!

Look at it as expansion rather than maintenance, I don't buy a battery every month or so because they fail, but because it's a way of increasing my capacity without a massive single outlay. I expect each to last a couple of years or longer depending upon how hard they are driven.

If your 160AH gives sufficient autonomy then there's no need to spend anything for a couple of years or until it loses sufficient capacity that your autonomy is no longer sufficient. I've actually not bought anything since the flooding as I don't relish lumping the things up 10 floors to our condo (the elevators are still not working). There's no more space in the rack anyway and the autonomy is still satisfactory. We now have temporary mains power so things are getting an easier life.

Thanks for the explanation.

So here comes another question.Why don't you use deep cycle batteries instead and also one bigger instead of a multiple of smaller ones.

With regular car batteries I understand that you lose about 40% of their capacity right away where deep cycle ones give a steady load until they are completely unloaded.

As with the rack,my understanding is that you can't mix used with new batteries.If one fails you will need to replace them all,so one bigger will be cheaper than several smaller ones.

[Crossy]

Those are not car batteries, they are sealed lead-acid as are used in most UPS's.

The system was never intended to be a main power source but purely a backup so the additional cost of deep cycle batteries was not deemed necessary at the time. If we were off-grid using wind / solar and thus discharging our batteries on a regular basis I would certainly have invested in deep-cycle.

Not had any issues with mixing batteries of different ages as yet but I do intend replacing batteries to a less important function when they reach two years of age.

I'm no battery expert, but I don't see that one failed unit would mean I need to replace them all, sealed lead-acid's tend to fail in a mode where they simply won't accept charge no matter what voltage is applied (effectively open-circuit) so all that would happen is that the one battery simply would not be providing power and the available capacity would reduce by that one battery.

I should add a fuse for each battery (and will when the system gets re-built later this year) to guard against electrode separator failure (shorted cell) causing large circulating currents.