Kerry - what you wrote about is not what was described. The supply=20 has a 2-wire AC input which is NOT connected to the output in any=20 way. The output DC common is connected to the chassis. This is=20 common practise. dwayne At 11:04 AM 7/11/2014, Kerry wrote: >I don't know if it's 'standard practice' or not, but it shouldn't be. >If the neutral and ground are tied together in the device, then there >will be current through the ground wire. There should NEVER be current >through the ground wire during normal operation. It will also trip a >GFI type device if one is used. DC common should be to neutral and the >chassis to ground. > > >On 7/11/2014 10:29 AM, Justin Richards wrote: > > Basically my question is, Is it standard practice to tie the SMPS DC gr= ound > > to the mains earth? > > > > I am re-using a metal case and its built in SMPS from a faulty digital = TV > > decoder to house the PI(D) oven controller. > > > > The chassis was connected to a 2 pin AC plug and as such was not earthe= d > > and the 0V/GND of the SMPS was tied to the chassis. (I thought such a > > device either has to be earthed or double insulated.) > > > > I have installed an IEC socket and IEC plug and about to connect all th= e > > earths to the metal chassis but noticed the DC ground is currently also > > tied to the chassis. I assume this is standard practice but cant > > definitely recall if I have seen a device wired this way. > > > > Justin > >-- >http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >View/change your membership options at >http://mailman.mit.edu/mailman/listinfo/piclist --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .