Here's my instantaneous hot water heater. It's a Mazuma MIS-45 (4.5kW). The web address is
ประวัติความเป็นมาของบริษัท MAZUMA
The first 2 pics are of my water heater.
The below pic is about the "ELCB".
Sorry about the poor quality pics but the writing says, "Warranty 2 years. Heater made in UK. ELCB Breaker."
This pic below shows the "earth" wire, which is black.
The pic below is of the cables going into/out of the Distribution Board (DB) in the Electrical Riser on my floor (12th floor). There are no signs of an earth cable/earth cables. There is, however, one cable that is sheathed in green sleeving. I don't know where this goes & no other cables seem to connect to it inside the DB. Therefore, there is not an effective earth for my hot water unit.
In Thailand, which has a disastrous mixture of both American & European electrical standards, the wiring colour code can be confusing.
In some cases, it follows the American method...black = hot (live/active), white/grey = neutral. For the European standards, an active/live/hot can be red, white, yellow, blue, or brown. Earth is always green or green with a yellow stripe.
One of the biggest problems (with single phase installations) in Thailand is that live/neutral polarity is not checked & in many cases not observed. If these 2 wires are incorrectly connected, someone can die very easily.
BTW, "ELCB" stands for Earth Leakage Circuit Breaker. Technically, these devices were voltage dependant & were to a great degree, unreliable. They have since been replaced with RCD's (Residual Current Devices), which act in a totally different manner to ELCB's. The problem is that many people still incorrectly describe RCD's as being ELCB's.