[TenTec] White Paper On Power and Grounding

[Jim Brown]

On Fri, 31 Dec 2004 11:41:11 -0800 (PST), Martin AA6E wrote:

>Am I missing something?  

I don't think you're missing a thing. 

To respond to John's question, I'll point out that I did address 
balanced power in the piece. The ONLY advantage of balanced power 
is that equal voltages are applied to bypass capacitors within 
equipment, as well as to other leakage capacitance that may be 
hanging between the AC line and the equipment ground. For that 
reason, the noise current in the ground has a better chance of 
cancelling, so the ground is quieter. This can translate to less 
current flowing on the shields of signal wiring, which in turn 
results in less noise being induced into the audio (or video) 
system. 

Balanced power systems are, IMO, strongly over-rated and over-
touted. They are more "audio jewelery" for those who know a little 
science (buzz words) but not enough to know they are being sold a 
bill of goods. 

I do agree with John that any electronic installation, including a 
ham station, will benefit from a dedicated circuit for the reasons 
you cite -- that is, it is less polluted by noise from other 
loads, and suffers less voltage sag when some other heavy load 
kicks in. That's because the only common conductors are the 
(larger) feeders to the breaker panel, not the (smaller) branch 
circuit conductors. And I also agree that shared neutrals are a 
bad idea, for the same reason. 

When I bought my 110-year-old house nearly 20 years ago, I put in 
a lot of conduit and re-wired it to put IG outlets everywhere and 
run dedicated phase, neutral, and IG home runs to every quad box. 
My ham shack has a dedicated 20A 120VAC circuit, as well as a 
dedicated 240VAC circuit. An air conditioner, sitting next to the 
shack, is on another dedicated 20A circuit. My office computers 
are on another dedicated circuit. And so on. 

Each of my electronic systems goes first to a SurgeX unit, then 
one or more multi-outlet strips. The computer rigs (mine and my 
wife's, in different rooms) each has a SurgeX followed by a UPS. 
The UPS's I use are Best Power (now called something else, thanks 
to a corporate acquistion). The UPS for my ham station consists of 
some big batteries that are float charged. 

I also addressed "reactive power" in the form of the section on 
harmonic current, which is really what is going on in electronic 
gear. BTW -- in Europe, the harmonic content and power factor are 
covered by some EU regulations.  That isn't true in the US -- it's 
between you and your power company, and you're only going to hear 
from them if you're a BIG facility. 



Jim Brown  K9YC