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What size breakers


Orinoco

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12 minutes ago, Cardano said:

I am using IEC standards and UK 17th Edition of wiring regulations, if you want to use Thai standards that's your choice. I have 18 way DB fully fitted with SP RCBO's and MCB's with incoming 100A isolator all conforming to the above standards and regs, PEA approved no problem. 

 

Oddly enough we are in Thailand, Thai regs apply.

 

Do you actually have a 100A ISOLATOR? Where is your installation over-current protection, there's no DNO fuse here.

 

Do you also have UK style ring-finals on 32A MCBs?

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I admit to finding it "mildly" annoying when a forum noob comes along and tries to impose a foreign wiring standard.

 

Try that in Oz and see how long you stay out of jail!

 

If you DO want to use a foreign standard here the closest to Thai system requirements would be AS3000.

 

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9 minutes ago, Crossy said:

 

Oddly enough we are in Thailand, Thai regs apply.

 

Do you actually have a 100A ISOLATOR? Where is your installation over-current protection, there's no DNO fuse here.

 

Do you also have UK style ring-finals on 32A MCBs?

Installation exceeds Thai regs requirement. Yes actually have 100A isolator with 80A kWh meter. You are correct there is no supply authority fuse here, so no protection up to DB. My DB is imported Schneider Iso-Bar fully encapsulated so is classified as fault free zone hence do not need protection on incomer. Yes my ring circuits are 32A, 30mA, 30mS RCBO's.

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1 hour ago, Cardano said:

Yes my ring circuits are 32A, 30mA, 30mS RCBO's.

You do realise that ring finals are deprecated in favour of 2 radial finals in the  U.K. and have been for quite a few years. The savings in cable are apocryphal and the 2 radials that replace them allow an extra 8A between them.

 

Using them in Thailand is dangerous unless you are the only one to ever do work on your electrical installation. 
 

Few if any Thai electricians trained or not have any knowledge of them or how to troubleshoot a problem. The have the delightful characteristic of a break in the circuit allowing the sockets to continue to be live so potentially the 32A breaker is just protecting a single 2.5mm circuit rather that the 2 x 2.5mm it is supposed to. Fun times? Maybe a packet of marshmallows near the metre would be appreciated, no? ???? 

Edited by sometimewoodworker
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2 hours ago, Cardano said:

you need to get your earth loop impedance tested to ensure less than 5 ohms, otherwise any earth fault protection equipment is useless.

An RCCD/RCBO is not reliant on a functioning earth as it detects a line neutral difference, though a functional earth is certainly preferable there is no guarantee that it will be involved in the trip fault.
 

earth fault devices ELCBs are deprecated in home use in favour of the RCCD as they work with and without earthed circuits

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  • 1 month later...

Back to my man cave. I am going with 6mm feed but the 'electrician' who came to look at what's been done already said I need to upgrade the 2.5mm wire (on a 20A CB) for the air-conditioner to 4mm. That's overkill IMO, especially since the aircon is on the same wall as the CU. The aircon isn't installed yet anyway so I will ignore him for now.

 

On another upgrade, there's a Thai style wooden house at the back of the property that's always had it's power via some 'romex' twin-core, maybe (hopefully?) 2.5mm that's daintily snaked across the top of a steel picket fence (I know, I know...). The sun has faded so no idea what gauge it is any more but it's going to be replaced. It looks like they installed a power pole for this distribution nearer the wooden house but either ran out of money (unlikely) or just got lazy and didn't bother getting the yellow conduit and other gubbins to run it properly along the wall, up the pole and across to the house.

 

So, this power also comes off the 'home' side of the main 100A service breaker in a box on the wall. The wooden house only has fluoro lights, floor fans and the like so what gauge/type of wire would be recommended for that run, maybe 40 meters total? Do they do proper Romex here with a bare ground wire between the insulated pairs?

 

Thanks!

NL

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9 hours ago, NanLaew said:

Back to my man cave.

 

Definitely no need for anything bigger than 2.5mm2 on your A/C unless you have pet penguins.

 

For the wood house, I'd bank on 20A max load (that will let you have a small water heater and A/C), at 40m that would want 4mm2, stick it on a 30A RCBO at the main house end. You may wish to run 2-core to the wood house (cheaper) and bash in a local rod to make a TT island. The local "Romex" equivalent would be VAF or VAF-G (with an insulated ground core). If running in conduit (and not underground) then THW single core would likely be cheaper.

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3 hours ago, Crossy said:

 

Definitely no need for anything bigger than 2.5mm2 on your A/C unless you have pet penguins.

 

For the wood house, I'd bank on 20A max load (that will let you have a small water heater and A/C), at 40m that would want 4mm2, stick it on a 30A RCBO at the main house end. You may wish to run 2-core to the wood house (cheaper) and bash in a local rod to make a TT island. The local "Romex" equivalent would be VAF or VAF-G (with an insulated ground core). If running in conduit (and not underground) then THW single core would likely be cheaper.

Aircon noted, thanks. The local 'electrician' is now on painting duty.

 

Will the 2 x 6mm fit inside 16 mm conduit? Since I will be running the ground from the CU out to the ground spike maybe best to run that in its own 16 mm conduit so that the ground end can be properly enclosed/maintained. Ideas?

 

If I run VAF-G and ground it, then there will be a temptation for the sister-in-law (in the wooden house) to cadge for the spare water heater for her shower. More 'remote' stuff for me to fix so the jury is still out on that.

 

Will the 4mm VAF or the VAF-G or the 2 x 4mm THW fit in 16 mm conduit? The run along the wall and up the pole would be in conduit with the last 4 or 5 m from pole to wooden house for the birds to perch on.

 

Thanks,

NL

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On 12/29/2021 at 7:37 AM, Crossy said:

 

Definitely no need for anything bigger than 2.5mm2 on your A/C unless you have pet penguins.

 

For the wood house, I'd bank on 20A max load (that will let you have a small water heater and A/C), at 40m that would want 4mm2, stick it on a 30A RCBO at the main house end. You may wish to run 2-core to the wood house (cheaper) and bash in a local rod to make a TT island. The local "Romex" equivalent would be VAF or VAF-G (with an insulated ground core). If running in conduit (and not underground) then THW single core would likely be cheaper.

WRT the "30A RCBO at the main house end", the wooden house feed currently comes off the switched side of the main isolator 100 A breaker mounted in a racer box on the wall outside the main house. I plan on replacing the box and the main breaker with newer stuff so would the following be an acceptable solution mounted beside the new main breaker in the new box for the feed to the wooden house?

 

30Aelcb.jpg.4e35980a9b28e6ea1f1b5e1fe2970640.jpg

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