On Mar 5, 7:08 am, RBM wrote:
...: Lightning and voltage spike devices are rated by "
clamping time", which is how fast they can shunt the spike, and by
"joules", which is the size of a spike that they can handle. I can buy
one for $5, and I can buy one for $20,000. I have always passed on the
$20K.

Protection is defined by the item that absorbs hundreds of thousands
of joules. That is not a protector adjacent to appliances that does
not even claim to protect from typically destructive surges. That is
earth ground.

The 'whole house' protector protects all appliances even from
direct lightning strikes because it connects destructive surges to
earth. The distance to earth is critical (ie 'less than 10 feet'). A
protector too far from earth and too close to the appliance can
connect that surge to earth destructively via the appliance. An
adjacent protector does not even claim protection.

Your 'whole house' protector also does not protect from surges.
Instead, it connects destructive surges to earth. Hundreds of
thousands of joules must be absorbed somewhere. No way around that
requirement.

Either you connect that surge to earth BEFORE it can enter the
building. Or that surge goes hunting for earth destructively via
appliances. With or without an adjacent protector.

A typically lightning strike is 20,000 amps. A minimally sized
'whole house' protector starts at 50,000 amps. Direct lightning
strikes must not even damage a protector. 'Whole house' protectors
are sold by the more responsible companies including General Electric,
Leviton, ABB, Siemens, Keison, Polyphaser, Square D, and Intermatic.
A Cutler-Hammer solution sells in Lowes and Home Depot even for less
than $50.

But again, most important is the item that absorbs those hundreds of
thousands of joules. Earth ground. To connect a surge to earth means
a protector must be low impedance (ie 'less than 10 feet') to that
single point earth ground. This is how it is done in every facility
that can never have damage. A protector is only as effective as its
dedicated and 'must always exist' connection to earth. The effective
protector is rated by how much current it can connect to earth. A
least 50,000 amps.