View Single Post
  #156   Report Post  
Posted to alt.comp.hardware.pc-homebuilt,alt.home.repair,alt.engineering.electrical,alt.tv.tech.hdtv,sci.electronics.basics
w_tom w_tom is offline
external usenet poster
 
Posts: 376
Default Surge / Ground / Lightning

On May 5, 2:19 pm, Mike Tomlinson wrote:
On properly grounded outlets, such a suppressor can deal with an
incoming surge on phase or neutral in an effective manner by conducting
and diverting current to the other leg AND to ground, but their
effectiveness when used on ungrounded outlets is reduced, since the path
to ground doesn't exist.


Include facts taught in first year electrical engineering OR
described in both 'top of the front page' articled in Electrical
Engineering Times on 1 Oct and 8 Oct 2007 entitled "Protecting
Electrical Devices from Lightning Transients" at:
http://www.planetanalog.com/showArti...leID=201807127
http://www.planetanalog.com/showArti...leID=201807830

That wire from wall receptacle is too long, has too many sharp
bends, has spliced, is bundled with other wires, etc. More reasons
why that safety ground wire is not earth ground wire. Protectors
without earth ground is not effective as Mike says. And AC wall
receptacle does not provide an earthing connection - wire too long -
too much impedance. Page 42 Figure 8 also demonstrates that problem
resulting in 8000 volts being earthing, instead, through the adjacent
TV.

Breaker box earthing wire goes over top of the foundation and drops
down to an earthing electrode. Compromised protection. Wire is too
long and has sharp bends. Better protection means wire goes through
foundation and down to that earthing electrode. Few meters less wire
and without those sharp bends means improved protection. Why? See
"Protecting Electrical Devices from Lightning Transients".

If earthng wire must be every meter shorter, then how does a
receptacle safety ground wire do earthing? Safety wire has maybe 30
or 50 sharp bends, numerous splices, and maybe 15 meters too long?
Low impedance connection to earth typically means 'less than 10
feet', or then even shorter for even better protection.

Obviously wall receptacle safety grounds do not provide earth
ground. But then Mike Tomlinson also did not understand the
engineering numbers in that EE Times article entitled "Protecting
Electrical Devices from Lightning Transients". Note the numbers.
Wall receptacle safety grounds cannot provide a low impedance
connection to earth ground. Engineers would know this. Mike
Tomlinson obviously does not.

Literally every incoming wire must make that short (low impedance)
connection to earth ground. If that earthing wire is not separated
from other wires (if that earthing wire is inside a bundle of romex
cables), then that earthing wire induces surges on those other wires.
Just another reason why safety ground is not earth ground. Just
another engineering fact that Mike Tomlinson read and did not
understand.

AC wall receptable is not an effective earth ground. Protectors
best make a less than 3 meter (low impedance) connection to earth
which wall receptacles just cannot provide.