Heres You New Post Forkinhades - Supply Size For Electricity

[Negita43]

Hello all you electrical gurus.

as you all know I've moved into my new house and last week I got an address so I want to change from the building supply I had to a proper supply. My Thai gf went to talk with the electric co and came back asking if 15 amps was enough! I dont believe she has got this right. Does she mean 15 KVA Anyway the meter on the supply I have for building is marked 15 45 Does this mean 15 KVA 45 amps The electrician installed a 100 amp trip under the house as a main breaker and the CU is rated at 63 amp. My supply cable (from the meter) is 25mm copper (half underground and half under house) as per Crossy's recomendation. In my house I will have (but not yet) 3 12000 btu inverter aircon 1 9000 btu inverter. Also I have a microwave, a dishwasher (love cooking hate washing up)and a washing machine IT IS HIGHLY UNLIKELY THAT ALL WOULD BE WORKING AT THE SAME TIME. In fact I would make sure they don't. So far on my 'builders' 15 45 I haven't had a trip. Can anyone advise me. Will 15 45 be OK or should I go for bigger (My gf tells me that the elect company are saying if I want bigger I will have to change the 25 mm copper supply) BUT she is even less of an expert than me and maybe she has got her live and neutrals mixed up (joke crossy and forkinhades etc) I mean her wires crossed. PS. As far as I am aware the supply in my street is single phase

Thanks all in advance

[Crossy]

Negita. You have a 45A supply (the 15 is the calibration current). Assuming the incomer in the CU is 63A you should be good to go (although the PEA inspector insisted that we replace ours with a 50A).

The next meter size is 30/100 for which PEA will want a 35mm² cable, so for now stick with the 15/45, it will be quite capable of 100% overload for short periods.

I've removed the post in the fuses thread.

[Negita43]

Tks Crossy

[Negita43]

The saga continues!

My dear, lovely, intelligent (but not very streetwise) gf went to the electric company to register the property and as far as I can ascertain told them that we are going to have 4 aircons, a lot of computer equipment and household appliances and now it seems that they are suggesting/insisting (not sure which) that we install another 25mm cable to deal with the load. (how I love her!)

I think this implies that 3 phase is available (I didn't think it was) in my area - am I correct in assuming this and that my power will then come from 2 phases and what does all this mean for cost/ operation. How does it work in practice?

Also you may recall the post about my RCBO and is it working? Well 3 nights ago we had a big thunderstorm right over the property and at one point a very loud thunderclap (and I assume lightening)The RCBO tripped but NOT the main breaker NOR the surge arrester which is part of the same CU. To my laymans mind I would have thought the surge arrester should have tripped. Any thoughts?

[Naam]

this is going to be fun! soon the sparkies will circle and land one after the other. codes will be recited, professional experience compared (measured in light years, megatons as well as amps per linear foot copper cable) and insults ad hominem exchanged such as "are you trying to tell me that an uncoded and tripped QBX is less serious than a hot RBO which is connected to a single UBC without being neutralised? where did you do your sparky apprenticeship? in a bakery?"

[jbrain]

Negita. You have a 45A supply (the 15 is the calibration current). Assuming the incomer in the CU is 63A you should be good to go (although the PEA inspector insisted that we replace ours with a 50A).

The next meter size is 30/100 for which PEA will want a 35mm² cable, so for now stick with the 15/45, it will be quite capable of 100% overload for short periods.

I've removed the post in the fuses thread.

Allow me to jump in with a question.

I have a 30Kva single phase transformer and a 30/100 Meter.

Between the cables that come from the transformer and the lead that goes to the house is a 100 Amp RCCB.

Inside the house I have 2 circuits whith each a 63 Amp RCCB

Cables coming from the transformer are fairly thick, but no markings on the cable so don't know the size.

Cables that go to the house are about half the size in my estimate, but again no markings on the cables so also no idea what the size is.

According to your post they should be 35 mm² , but how to I measure them? I think it's not as simple as just measuring the diameter isn't it.

Edited April 25, 2013 by jbrain

[Negita43]

Naam, With 22,0000+ posts I clearly have to respect you BUT I don't know what your post has to do with my question - you are clearly not of this planet and your picture seems to confirm that!

[Crossy]

According to your post they should be 35 mm² , but how to I measure them? I think it's not as simple as just measuring the diameter isn't it.

You can make a rough estimate by measuring the outside diameter of the cable and then looking at this table http://www.bangkokcable.com/catalog/BCC_CATALOG/THWEN.HTML better if you can measure the diameter (D) of the copper (but take care, power off of course) and calculating the area pi*(D/2)² .

[Naam]

Naam, With 22,0000+ posts I clearly have to respect you BUT I don't know what your post has to do with my question - you are clearly not of this planet and your picture seems to confirm that!

go to the thread out of which Crossy pulled your question and read, weep or laugh heartily

http://www.thaivisa.com/forum/topic/631779-fuses-breakers-amps-max-load-crossy/#entry6284370

[jbrain]

According to your post they should be 35 mm² , but how to I measure them? I think it's not as simple as just measuring the diameter isn't it.

You can make a rough estimate by measuring the outside diameter of the cable and then looking at this table http://www.bangkokcable.com/catalog/BCC_CATALOG/THWEN.HTML better if you can measure the diameter (D) of the copper (but take care, power off of course) and calculating the area pi*(D/2)² .

Thanks will have a measurement tomorrow. I see in the table you provided that they go from 25-35-50 mm², does that mean that NYY cable is not available in a size between ?

So my cable will be either one of these sizes, but not 32 or 38 ?

[bankruatsteve]

The saga continues! My dear, lovely, intelligent (but not very streetwise) gf went to the electric company to register the property and as far as I can ascertain told them that we are going to have 4 aircons, a lot of computer equipment and household appliances and now it seems that they are suggesting/insisting (not sure which) that we install another 25mm cable to deal with the load. (how I love her!) I think this implies that 3 phase is available (I didn't think it was) in my area - am I correct in assuming this and that my power will then come from 2 phases and what does all this mean for cost/ operation. How does it work in practice? Also you may recall the post about my RCBO and is it working? Well 3 nights ago we had a big thunderstorm right over the property and at one point a very loud thunderclap (and I assume lightening)The RCBO tripped but NOT the main breaker NOR the surge arrester which is part of the same CU. To my laymans mind I would have thought the surge arrester should have tripped. Any thoughts?

Based on what you have - you should be good. Methinks you should stop worrying. Not sure what kind of surge arrester you have, but that would usually involve replacing an MOV vs something that has "tripped". Chances are that the lightning static charge tripped your RCD but not close enough to damage your surge suppressor.

[Negita43]

Hi Bankruatsteve, Thanks for your help. at 69 years old I've long ago stopped worrying about anything BUT I like to understand things and that's what keeps me young in the mind if not in the body!

[Negita43]

Hi Naam , Of course my post was tongue in cheek- I understood the innuendo, I just hope you survive the duel when it happens.