I don't know if it's 'standard practice' or not, but it shouldn't be. =20
If the neutral and ground are tied together in the device, then there=20
will be current through the ground wire.  There should NEVER be current=20
through the ground wire during normal operation.  It will also trip a=20
GFI type device if one is used.  DC common should be to neutral and the=20
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 grou=
nd
> 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 earthed
> 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 the
> 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

--=20
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