In the US, ground is bare copper, green, or green and yellow.
Neutral is white or grey
And hots are any other color, with black, red, and blue being common for lower voltages, and brown, orange, and yellow being common for higher voltages. But that’s just an unofficial standard, you can run all hot pink wires for your hots if you really wanted to.
Meybe he thought that since the wires are same color, nothing will halpen. Seriously who wired this.
This bit is probably specific for eu: Yellow (well yellow-green atleast) is suppose to be effin GND.
In the US, ground is bare copper, green, or green and yellow.
Neutral is white or grey
And hots are any other color, with black, red, and blue being common for lower voltages, and brown, orange, and yellow being common for higher voltages. But that’s just an unofficial standard, you can run all hot pink wires for your hots if you really wanted to.