On Friday, February 10, 2017 at 11:46:00 AM UTC-5, westom wrote:
On Thursday, February 9, 2017 at 9:36:52 PM UTC-5, Diesel wrote:
In part? Er, no. That's the primary reason the protector and
everything else wasn't damaged/destroyed. Your house protector does
the same thing the plugin surge protectors do on a larger level. It
tries to redirect excess current on either/both legs to ground, to
bleed it off as quickly as is possible.

You assumed resistance is relevant. It is not. Impedance is the relevant parameter. Plug-in protectors are all but completely disconnected from earth ground. Plug-in protectors must somehow 'block' or 'absorb' that energy. Plug-in protectors operate completely different from a properly earthed 'whole house' protector.

An answer without numbers is best ignored as speculation. That plug-in protector may connect to a breaker box by wire that is well less than 0.2 ohms resistance. That same wire may be 120 ohms impedance. If that plug-in protector tried to earth a tiny 100 amp surge, then 100 amps times 120 ohms impedance means protector and appliances approach 12,000 volts.

The surge sees that same impedance, which is why 12,000 volts never
get to the appliance. You get arc over, most of the energy diverted.




Plug-in protectors can make appliance damage easier if not part of a properly earthed 'whole house' solution.


The IEEE and NIST both say that's BS. Of course that's been presented
here to Tom by several of us, with cites to the relevant documents,
but Tom just drones on and misrepresents what IEEE and NIST engineers
say and show.