Cable Tray or Earthing Strip

It is not allowed to connect motor cover to cable tray, even if cable tray is connect to earth (through MCC earthing strip or directly connect to earth) according to IEC (you can not use electrical equipment or their support as earth conductor). normally, in your case, we use a separately earthing cable run through cable tray and this cable is earthed at the starting point.

→ British Standard 7671.

There should not be any compromise in safety of personnel and equipment.Proper Earthing System comprising of required No. of Earth Electrodes,interconnecting main Earthing strips as per IS:3043/IEEE80 guide should be provided for each plant/shop.Each equipment/panel/MCC /cable racks/pipes/MS structural columns etc of the concerned plant/shop which are not supposed to carry electric current , should be connected to the main earthing ring/strip at minimum two points through separate earthing strip/cable.

You may do the needful accordingly.

In my opinion , current faul will flow , but assuming that tray is iron or similar against cooper material you are adding a ground resistance , having as a result higher ground resistance and depending on the short circuit current you can heat trays and diminish grounding protection.

It is definitely a grossly incorrect practice to earth the motors thro the cable trays. You must run sepearte earthing conductors throughout your plant and connect your motor bodies to this earthing conductor only.

Of course, in the event of an earth fault, your (I assume, metallic) cable trays will definitely carry the fault current, but, then what would happen to the cables laid in the cable tray due to the heat developed by the cable tary while it carries the fault current.

defiantly ! the fault current will flow, so that u maintain the earth value bellow 1 ohm in the main grid