p { margin-bottom: 0.25cm; line-height: 120%; } As long as the blue and the yellow-green are not live, then everything is ok. But due to national differences in the past and international harmonization in recent years the color coding can be really confusing (especially if done by a foreign worker (German, Austrian, Italian, French, Protuguese, Spanish, ... ) or house owner/ who is used to a (sligthly) different coding scheme) can things really mess up. Therefore, it is not stupid to check it before. However, the new standard is valid since 2001.
But in general, according to the latest, international standard, for the case of single-phased 220/230V AC :
- yellow - green (since 1965, yellow-red in older Swiss days) should be the PE line (grounding, earth line, " Schutzleiter PE ", "Erdung", in Germany also called: "Mittelleiter", in Austria: "Erde"), and
- blue ( yellow in older Swiss days until 1989, light blue in earlier German days) should be the neutral line (" Neutralleiter ", in Germany: "Nullleiter"), and
- brown (sometimes also red, black, or white, or even blue! (or orange, violett, ...)) for the active line (" Polleiter ", "Phase", " Phase L ", in Germany also called: "Aussenleiter")!
see here: http://www.bruggcables.com/domains/b...D_308_S2_d.pdf
From 2001: https://www.ktipp.ch/artikel/d/laien...ht-zu-scheuen/
Further, in Europe the low-voltage socket CEE7/4 ("Schukosteckdose") is symmetric and does not define on which side the active and the neutral line is!
For 3-phased installation see here: http://de.wikipedia.org/wiki/Nieders...etz#Farbgebung