IEC Wiring Conventions

[LRMesh]

Understanding the majority of the wiring conventions in most of the European prints I have come across, I have run across something I can not find information about. I am talking about a particular column (say column 2). Going into a 3 phase device the wires are labeled 221 222 223. On the load side they have 1221 1222 1223. I would have thought I should have seen 221 223 225 and on the load side 222 224 226. Can anyone direct me to some information where I can find out why the 1221 etc numbers or give me some feedback on them. Thanks

 

[RalphChristie]

Unfortunately I can give no code-reference, but I have seen it sometimes used if an additional part (meter, testblock, safety device, etc) is added afterwards - thus if the wiring is already numbered and connected, and an extra part is added.

Regards
Ralph

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