IEC 2010 limit switch wiring
 

Where is the ground on this year's limit switches?
Also, is there a difference on the 13 and the 14 connections for the NO side and the 21 and 22 connections for the NC side
-Shubert

Re: IEC 2010 limit switch wiring
 

"NO" and "NC" beside two of the contacts stand for Normally Open and Normally Closed.
You chose one set of contacts or the other.

You connect to the contacts 13 & 14 if you want Normally Open.
Use contacts 21 & 22 if you want Normally Closed.
Wire signal to one of the contacts and ground to the other. It doesn't matter which, because a switch just completes a circuit. Direction of the subsequent current flow doesn't matter.

Most switches give you the option to appear to your code as

• an open circuit unless pressed (NO)
• a closed circuit unless pressed (NC)

There are reasons for using each. For instance, I'd use Normally Closed for a safety switch, because if the switch becomes disconnected the circuit will open and my code will stop whatever is moving to prevent an accident.