Short circuit testing of Terminal box of Ex 'd' medium voltage (11kV) induction motor

[sanjivk4]

I have following requirement in my Ex'd' 11kV motor specification - For MV Motor terminal box shall be capable of withstanding the fault current for a period of 0.25 seconds specified in the motor datasheet. However, motor vendor Siemens has informed that for Ex 'd' motors, they do not perform short circuit test for terminal boxes separately as it is already covered in ATEX type test certificate which covers complete motor tsting including its terminal box. What I understand Ex'd' ATEX certificate applicable only for explosion protection of motor body not for short circuit testing of terminal boxes. Please suggest any IEC/IEC which lists that short circuit testing of terminal boxes shall be performed separately irrespective of ATEX Ex'd' certification of 11kV motor.