[Amps] 220V wiring: Was Question about safety ground connection

[Bill Aycock]

Louis
Thanks for the kindergarten lecture. What you told me and what was in 
the link was WHAT happens, not HOW. You also included a lot of extra 
stuff about "side" connections and "back stab", that do not help.
I know what wires are, and even the difference between #12 and #14, and 
why copper is better than aluminum for house wire. I even have wired to 
code, and passed inspection. What I don't know is what I asked- "how 
does it work?" I mean what is measured?, what is compared?. A GFI 
measures the difference in current in two wires, to see if some current 
is going where it should not.
If this gadget can tell the difference between a normal contact arc and 
an abnormal one, how does it tell?
Even though it was on a .gov site,the link was to a Flack sales job on 
why we should use this thing.. I want something that relates to the laws 
of physics. Things like rise rates, pulse shape, delays or count, 
frequencies,etc.
Incidentally- what was in the link did NOT rule out action as a result 
of RF at HF frequencies. In fact, I don't remember any reference to RF 
at all- I need to recheck that.
Bill-W4BSG

Gudguyham at aol.com wrote:

> In a message dated 11/19/2005 6:31:33 P.M. Eastern Standard Time, 
> baycock at direcway.com writes:
>
>     That thing tells nothing about HOW the thing works- it reads like
>     it was
>     written by an Ad Flack, not a technical person.  If you find a real
>     description, I would like to see it.
>     Bill-W4BSG
>
>  
> Bill, Indeed that piece told how the unit works.  If you missed it, it 
> said that the arc fault breaker monitors the current on the line being 
> drawn by the circuit.  If there are minute fluctuations of current ie: 
> sparking or arcing the breaker shuts down.  In normal use of current 
> the variations are "smooth" if you will.  In the case of arcing the 
> variations are more rough, the breaker senses this and shuts down.  
> This was explained in the link I sent you to.  It also went on to say 
> that the "one time arc" of a light switch turning on or a plug being 
> plugged in with a load on it will not trip the breaker because if is a 
> "one time" occurrence.  There needs to be more of the arcing in a 
> shorter period of time to have it shut down.  I suppose if you 
> switched on the light switch quick enough in a short time, it might 
> trip, but I am not sure if that "waveform" would be rough enough to 
> shut it down.  Since these breakers are relatively new and the code 
> does not require them yet in ALL areas of the US I have not had any 
> experience with them yet.  However, I have heard from my other 
> electrician friends that have, that they are a "nightmare".  Indeed 
> many  a house fires have started as a result of arcing of poor 
> connections at outlets and switches.  Since it is not an over current 
> situation a regular breaker will not catch this problem and a fire can 
> result.  MANY older houses were wired with "back stab only" devices.  
> In the case of the "back stab only" outlet that one plugs a vacuum 
> cleaner into everyday (some women are anal about this) eventually the 
> connection loosens up and begins to arc, hence, any other load that is 
> also connected downstream or at the same outlet will continue to arc 
> the connection, heat is generated and the wire starts to burn, if 
> conditions are right a fire can start from the high temperatures the 
> arc has caused on the wire.  Many old outlet boxes have dust in them 
> and dust can ignite quickly.  Needless to say I DO NOT "back stab" any 
> devices.  When getting electrical estimates you should specify "side 
> wiring" or else the "cheap" bid on the job will most likely be back 
> stabbed.  Fortunately however newer devices will not accept #12 wire 
> as a back stab.  Its a start in the right direction.  73 Louie W1QJ


-- 
Bill Aycock W4BSG
Woodville, Alabama