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Feedback: From an Electrician

*feedback from David V

Great web site. I think there’s a mistake in the “Electrical” section. It mentions a size 16 ground wire (proper term: “grounding electrode conductor”) which is bonded to the ground rod. This wire should run from the ground rod to the main bonding jumper (neutral to ground bond), which should be located in the main panelboard. In the picture of the panelboard, there is one larger black colored conductor bonded to the ground bus. I assume this is the grounding electrode conductor, and it appears to be a #6 or #8 (American Wire Gauge, or AWG.) #16 AWG conductors are only used for control wiring.

The same panelboard picture has me concerned about something else. The 2-pole, 45 Amp main circuit breaker appears to have #12 AWG conductors (the two white ones on the bottom left). Are these coming from the meter box? If so, these wires are rated for 20 Amps, and would burn up before the 45 Amp main trips. And 45 Amps sounds low, unless you do not have air conditioning.

>Good catch. The picture of the circuit breaker in the [electrical section](../infoelectric.htm “electrical info”) was prior to completion and has been replaced now. The circuit breaker shot there not shows the correct heavy 16 gauge grounding electrode conductors.

I’m not familiar with Thai Electrical Code (or if there is one), and my source is the National Electrical Code (NEC). But wire and circuit breaker sizes should be international, and it appears you’re using Square D circuit breakers (in which case my wire sizes are correct).

Obviously, you don’t have to follow the NEC (which requires a 60 Amp minimum sized main circuit breaker and an 8′ ground rod (5.5 meters)), but you should have a system that is safe. That’s why in the USA, we require a licensed electrical engineer to sign the electrical drawings. I would not recommend the owner create these plans, as you suggest.

As far as the 45 amp main (on the left), we had a move expensive 63 amp one in there and the city inspector made us take it out and replace it with the 45. I don’t know why exactly, but it is the same for every house.

Anyway, if you have any questions I’ll be glad to help. I create these drawings all day at work, while daydreaming about Thailand. By the way, a house like this in Salinas, California would cost at least 20 million baht.

David V, P.E

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  1. I posted a comment yesterday about Thailand’s electricity supply and my experiences with inserting a simple on/off switch between an ornamental lamp and the mains supply. The switch was a sealed unit with a hole for the live wire and a hole for the neutral. I managed to crack the switch apart only to find that the click button would move the buzzbar inside the wrong way. Net result a dead short! which caused the fuse box to throw a tantrum and I had to remove the plug and reset all the circuit breakers. Now I have replaced the switch, I have no problems switching the lamp on and off. I did wonder about how many amps where pushed along by the voltage and of course this depends on the Watt rating of the bulb. First I tried a 12 Watt bulb which would mean the current (amps) would be would be 220 (volts) divided by 12 resulting in a current of 0.42A. The receptacle in the lamp allows any bulb of any wattage to be screwed in. I have now gone down to a yellow 5 Watt bulb which would mean a current of 0.02 A would be drawn. Despite there being no ground. I am hardly likely to die if I accidentally touched the base of the bulb whilst the lamp was in the on position. Thanks to the other posts for jogging my memory of schoolboy physics. Oh BTW David V,P.E 20 million baht sounds horrendous but you will get between 30 and 40 US dollars to the Thai Baht. I keep my eye on GBP (£) being a Brit expat. I would currently expect around 40.46 Baht for each £ of my money in my U.K. Bank.

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