[Amps] Electrical Distribution Methods

Jim Thomson jim.thom at telus.net
Fri Oct 18 07:16:38 EDT 2013


Date: Wed, 16 Oct 2013 23:19:43 -0700
From: Jim Brown <jim at audiosystemsgroup.com>
To: amps at contesting.com
Subject: Re: [Amps] Electrical Distribution Methods

On 10/16/2013 9:36 PM, Jan Erik Holm wrote:
> Not that I like to mark words but it?s more correct to say "between 
> one phase and neutral". The neutral is also grounded but at the 
> distribution transformer side. 

Yes. It is always important to understand the difference between neutral 
and ground.  Neutral usually carries load current, ground must never 
carry load current. The only function of ground is SAFETY.  In most 
countries, the "ground" wire must be connected to the chassis, and is 
there to blow a fuse or trip a breaker if the chassis becomes hot 
through some fault. In nearly all countries, neutral is connected to the 
ground wire, but WHERE and HOW it is connected varies widely from one 
country to another. In North America,.neutral must be bonded to the 
"green wire" (ground) where power enters a building, and again at the 
secondary of any transformer.

73, Jim K9YC


###  I think you might be missing the point here.  In the UK and else where, the
220/230/240    consists of hot and neutral.  Neutral is also grounded on the sec
of the xfmr.    IE:  their  220/230/240 is UNBALANCED to the home.  

##  here in Canada and the usa,  the  240 vac  is BALANCED.  In Canada + usa, the
12.5 kv / 14.4 kv single phase  input to the is UNBALANCED.   In the event of a primary
to secondary short in the single phase xfmr, the sec needs to be grounded some where
....hence the grounded CT on the sec.   In fact the CT on the sec is looped back to the
Grounded side of the xfmr pirmary..and done right at the xfmr.   You can see that plane as
day with the xfmr in front of your home.   Of course, the CT is also the grnded neutral.....
and grnded  again at the main 200A panel in the home. 

##  In the UK you have both an UN balanced primary....and  an UN balanced sec.     The grnded
side of the pri..is bonded to the grnded side of the sec.   Same deal, if a pri to sec short in the xfmr
ever happened.... u have a path for fault current..and the HV fuse simply blows open.   You don’t
want 12.5 kv or 14.4 kv or any HV  coming into the home.   

Jim  VE7RF 


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