Dear list contributors,

Could people working under different electrical standards advise on practice re earthing (one side) of control transformer secondary at
different voltages say 110 Vac, 48 Vac and 24 Vac and also 24 Vdc control supplies?


Regards

Martin Cutajar

ETAS&S Ltd
Tel.: +356 417748,
Fax.: +356 417747,
Mobile: +356 (0) 949 0708,
e-mail: [email protected] or [email protected],
postal address: P.O. Box 13, Rabat RBT 01, Malta.

 

The purpose behind grounding the common side of the control transformer secondary, is so that if the Hot or Line side develops a short circuit to the frame of the machine or control panel, that the fuse/breaker will clear and not leave the frame at the 110V potential, thus exposing humans to the possibility of electrical shock. It is standard practice and usually required by code whenever you have a higher voltage such 110V.