Zener Barrier in MV Switchgear

[NickParker]

We have RTDs from motors connected to the digital relay in the switchgear, and the specification states that RTDs should not be Exia to avoid the need for zener barriers. What would be the consequences of having a zener barrier in the switchgear (located in safe area, indoors)?

 

[Heaviside1925]

OP,
Can you clarify, the specification for what? or even link the specification?