House wire to light is red and white, lamp to be fitted brown and blue! no earth of course. Which are the 2 positives red and brown? Seen quite a few variations here. 

The only way to tell which of the ceiling wires is "live" (it's AC, no positive and negative) is to test using a live wire tester, the simplest of which is a "neon screwdriver".

 

Whichever turns out to be live you should connect to the brown wire in the fitting.

 

In reality for a light, it makes no odds, either way round will work just fine.

 

Does it make any difference for a led lamp ?

i know for incandescent, it does not .

Just now, degrub said:

Does it make any difference for a led lamp ?

i know for incandescent, it does not .

 

This is led, still does not work managed to take a shot of the wiring, not lose so rat has not eaten through but does not look right, worked for 12 years. Switch is ok as it controls another light. Looks like taking the ceiling down. Looks a bit dogdy going over the wall to the switch

 

Take the light down and try it with a plug into an outlet, verify that the light works.

2 hours ago, proton said:

House wire to light is red and white, lamp to be fitted brown and blue! no earth of course. Which are the 2 positives red and brown? Seen quite a few variations here. 

There are not 2 positives. That is an American 120V half phase system where to get 200+V you need 3 wires (the 2 half phase (I know that they are technically 1/3 phase) and for 120V (often 110) you need 2

 

Thailand has single phase 220~230V and 3 phase 380+V

 

So you need 1 line and 1 neutral (preferably 1 earth) because this is Thailand any colour will be used. So you need to test to be sure. Typical colours for neutral are white or blue, typically colours for line are red, brown, black. But see above never trust before testing, of course there is the problem that your LED could be 12V.

 

Typically, 220v LEDs will have a bridge rectifier in the fitting so it will not matter which cable is line or neutral 

2 hours ago, proton said:

House wire to light is red and white, lamp to be fitted brown and blue! no earth of course. Which are the 2 positives red and brown? Seen quite a few variations here. 

 

Buy yourself a meter, cheap on Lazada