In the US the NEC (national electrical code) specifies that neutral and ground (earth) are to be tied together at the building entrance. They must be kept separate everywhere within the building. ~ Bob Ammerman RAm Systems -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of Vitaliy M Sent: Friday, July 11, 2014 3:17 PM To: Microcontroller discussion list - Public. Subject: Re: [EE]: Grounding SMPS and earthing. On Jul 11, 2014, at 10:26, Justin Richards wrote: >=20 > Earth and Neutral are connected > together in the meter box where the power enters the house. AFAIK this is not true in most cases, at least in North America. Earth is a separate conductor, connected to an earthing rod. -- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/chang= e your membership options at http://mailman.mit.edu/mailman/listinfo/piclist --=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 .