I need 20 amps

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jovial fucher
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Re: I need 20 amps

Post by jovial fucher » Tue Dec 17, 2019 7:36 am

Thanks everyone. I have learned a lot! :bow:

Mostly, I have learned that even if a 20 amp connection is available, it's going to cost me about 200 to get it. That's more money than I want to spend on something that isn't mine.

I'm going to stick with tepid showers in the AM and warm showers when the sun is high. As long as nothing catches fire, I'm going to live. :plus1:
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Kammekor
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Re: I need 20 amps

Post by Kammekor » Tue Dec 17, 2019 7:40 am

timmydownawell wrote:
Tue Dec 17, 2019 7:06 am
Kammekor wrote:
Tue Dec 17, 2019 6:08 am
AFAIK a 20A circuit braker is not available from EDC. It’s either 10 or 32A. The price difference is pretty steep If you want a new connection to the grid But I don’t Know what They Will charge for an exchange.
Looks like they do offer it. This doc is in Khmer though:
https://www.edc.com.kh/images/list_of_e ... 6_0001.pdf

I'm not sure what the columns are but one might be the "deposit", followed by the price and then the total as that is about the same as I paid for 63A.

20A costs 351,000 riel
32A is 762,000r
63A is 1,511,000r
Those are the prices for a new connection to the grid. According to the document 20A is available. This is the price for registration of your connection with EdC plus the installation of the circuit braker, usually in a box on the road in front of your house. In large building it's usually inside.
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timmydownawell
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Re: I need 20 amps

Post by timmydownawell » Tue Dec 17, 2019 7:54 am

Kammekor wrote:
Tue Dec 17, 2019 7:40 am
timmydownawell wrote:
Tue Dec 17, 2019 7:06 am
Kammekor wrote:
Tue Dec 17, 2019 6:08 am
AFAIK a 20A circuit braker is not available from EDC. It’s either 10 or 32A. The price difference is pretty steep If you want a new connection to the grid But I don’t Know what They Will charge for an exchange.
Looks like they do offer it. This doc is in Khmer though:
https://www.edc.com.kh/images/list_of_e ... 6_0001.pdf

I'm not sure what the columns are but one might be the "deposit", followed by the price and then the total as that is about the same as I paid for 63A.

20A costs 351,000 riel
32A is 762,000r
63A is 1,511,000r
Those are the prices for a new connection to the grid. According to the document 20A is available. This is the price for registration of your connection with EdC plus the installation of the circuit braker, usually in a box on the road in front of your house. In large building it's usually inside.
Well it is comparable to what I paid. There was only a 5A connection here when I moved in but no-one had lived here for 18 months.
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Re: I need 20 amps

Post by Captain Bonez » Tue Dec 17, 2019 8:34 am

jovial fucher wrote:
Tue Dec 17, 2019 7:36 am
Thanks everyone. I have learned a lot! :bow:

Mostly, I have learned that even if a 20 amp connection is available, it's going to cost me about 200 to get it. That's more money than I want to spend on something that isn't mine.

I'm going to stick with tepid showers in the AM and warm showers when the sun is high. As long as nothing catches fire, I'm going to live. :plus1:
Just do what I do, don't use the hot shower and AC at the same time. Problem solved :thumb:
Keep your money in your socks and fuck, and get massaged, with your socks on

This.

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jovial fucher
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Re: I need 20 amps

Post by jovial fucher » Tue Dec 17, 2019 9:52 am

Captain Bonez wrote:
Tue Dec 17, 2019 8:34 am
jovial fucher wrote:
Tue Dec 17, 2019 7:36 am
Thanks everyone. I have learned a lot! :bow:

Mostly, I have learned that even if a 20 amp connection is available, it's going to cost me about 200 to get it. That's more money than I want to spend on something that isn't mine.

I'm going to stick with tepid showers in the AM and warm showers when the sun is high. As long as nothing catches fire, I'm going to live. :plus1:
Just do what I do, don't use the hot shower and AC at the same time. Problem solved :thumb:
If only I can remember that when I'm woke and boke. :facepalm:
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Re: I need 20 amps

Post by monomial » Tue Dec 17, 2019 6:42 pm

Also consider there is a huge difference between continuous load and short term. So you can probably use the shower and air conditioner at the same time, as long as your shower only lasts a minute or so.

Anyone interested (the TL;DR is "Don't believe anyone. Calculate it yourself."):

The ultimate load you can pull through a cable is dependent on how hot you want to allow it to become. Ultimately, the PVC insulation will start to melt at about 105°C, so you want to make absolutely certain you keep the cable under that temperature by a good margin. There are several things to consider when you do this. What is the external environmental temperature? In a hotter environment (i.e. direct sun) you will have less margin than if the cable is inside in a cool room. As I mentioned previously, if the cable is exposed and clipped to a wall, you can get a lot more current than if you enclose it in a conduit. This is because the air will carry the heat away and keep the surrounding air cooler, allowing the cable to more easily dissipate the heat. You can calculate the exact amount of heat you can dissipate at any given external temperature by using the Stefan-Boltzmann calculator here:

http://hyperphysics.phy-astr.gsu.edu/hb ... an.html#c3

You just need to fill in the appropriate parameters. Technically this only works for thin walled insulation (where there is a negligible temperature gradient from inside to outside), but that is a good approximation in this case. Also, this assumes purely radiative heat. Convection will only improve this number. Add any type of wind, even a small one, and you can get even better cooling. This is why you put fans on heat sinks. Another consideration is that if your electrician wired individual hot/neutral cables rather than the standard paired cable in white (they do this often if you request them to run a ground wire because it is cheaper to buy 3 individual wires than it is to purchase preformed 3 wire electrical cable) then you can actually carry slightly more current. But this is a pretty small effect.

Understand though that it takes time for things to heat up. So for a short period, you can exceed the maximum continuous capacity, and the extra heat will be absorbed by the insulation. Only once that reaches its maximum heat capacity and starts to melt are you really in trouble. If you shut down the current before that, the cable will cool off and everything is fine.

All of the above is just to point out that what you see electricians quoting are all just rules of thumb. No electrician actually does these calculations and determines what is safe. They simply tell you what someone else has told them is a safe margin in worst case conditions, and most of the time these numbers in the West are wildly conservative due to legal issues. However, it is worthwhile to note that even the European Harmonized Code allows up to 20A through 1.5mm wire under certain installtion conditions.

The truth is that 1.5mm cable is the most common because it works for circuits up to 20A in this environment and is basically safe. It is used throughout SE Asia (not just Cambodia) and there are millions of homes that prove its suitability. When there is a problem, it is generally because of improper installation, rather than because the material itself was improper. If you are going to survive over here, you need to become an expert on everything, because you can not rely on the experts here. For every one guy who knows what he is doing there are 20 who are just doing whatever they want. You need to educate yourself and understand the physics, because you can't trust anyone else.

Most air conditioners draw between 5A - 7A continuously when the compressor is on, which is why 1.5mm is the norm. Even a big, 40,000 BTU inefficient model will only pull about 12A, so you could probably get by with 1.5mm, but I like to have good margins so I would probably prefer 2.5mm in that case.

You can now go back to waiting for your power to short out because electricians over here simply twist wires together and cover them with masking tape rather than using a proper wire nut. You guys are worried about wire size? This problem is a million times more worrisome than that.
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Re: I need 20 amps

Post by explorer » Wed Dec 18, 2019 12:54 am

monomial wrote:
Tue Dec 17, 2019 6:42 pm
The truth is that 1.5mm cable is the most common because it works for circuits up to 20A in this environment and is basically safe. It is used throughout SE Asia (not just Cambodia) and there are millions of homes that prove its suitability.
All of the references I have seen say 1.5mm cable is not suitable for 20A. Here is one reference:
The following wire areas were translated from a Chinese Electrical Code Manual Ampacity Table.

1.5 mm2 - 15 Amp
2.5 mm2 - 21 Amp
http://www.ronhuebner.us/wire_sizes.htm

In Australia, there is a greater margin of safety. That is, the same size wire is used for less amps.

I know, in Cambodia, a lot of electrical wiring is very dodgy. A lot of them get away with it because they actually use less amps than they say the circuit can supply.

But it is very bad advice to tell people to use undersize wires. Sooner or later, this will cause fires. Sooner or later, someone will be killed.

It is sad when foreigners come here and discover a lot of things are dodgy. So they think it is OK to do everything dodgy themselves.

It is sad when people don't care about safety or human life, if they can save a few dollars.
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explorer
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Re: I need 20 amps

Post by explorer » Wed Dec 18, 2019 7:03 am

explorer wrote:
Wed Dec 18, 2019 12:54 am
In Australia, there is a greater margin of safety. That is, the same size wire is used for less amps.
For those interested, In Australia,

1.5 mm2 is used for 10 Amps, and
2.5 mm2 is used for 16 Amps.
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Re: I need 20 amps

Post by pczz » Wed Dec 18, 2019 12:16 pm

What about the other loads like fridge freezer? If you go to low you might find your ice cream melting when you put on aircon and have a shower
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Re: I need 20 amps

Post by explorer » Wed Dec 18, 2019 12:30 pm

pczz wrote:
Wed Dec 18, 2019 12:16 pm
What about the other loads like fridge freezer? If you go to low you might find your ice cream melting when you put on aircon and have a shower
No.

If you have an appropriate circuit breaker for the wire, and you draw too much power, the circuit breaker will turn off. So you wont have any power at all. You will need to turn off something, or when you turn it on again, it will just turn off again.

If the wire is too thin for the rating of the circuit breaker, it may heat up, and possibly start a fire.

There is another issue. If you have thin wires over a long distance, there may be voltage drop, which may cause things to not work properly.
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