text: <s>[INST] E-Stop Control Circuit Integration and CSA Z432 [/INST] Ouenuga, The use of a Safety Relay with the E-Stop button will satisfy the requirement of needing a separate Reset button input to be able to re-engage the motor starter. However a safety relay alone will NOT ensure that motor power is removed in the event of the motor contactor welding. A Safety Relay only removes power from the contactor coil. It is difficult to interpret what they may mean by this, but in some assessed safety requirements, it is necessary to have two contactors in series; one as part of the motor starter that is turning the motor on and off in the course of regular operations, and a second Safety Contactor ahead of it that only opens in response to the Safety Relay, so is thereby less subject to the conditions that might cause it to weld. The Safety Contactor is not a regular motor starter in this case, it is specifically rated as a Safety Contactor, having what are called “force guided contacts” and bearing specific approvals. These type of requirements would be outlined in a Safety Assessment of your machine by a qualified individual. Most of these machine safety requirements come from IEC requirements, Canada has apparently adopted them almost directly, the US is still indirect in that matter. Although none of this is specifically REQUIRED yet by NFPA 79, it is accepted as a compliant solution if implemented. However to be compliant with CSA Z432, the Safety Assessment is I believe prescribed (I'm not Canadian but I have read the document and outlines this in the first part of it). \\n </s>