On Thursday, May 19, 2016 at 11:10:53 AM UTC-4, westom wrote:
On Wednesday, May 18, 2016 at 10:56:06 PM UTC-4, Steve Stone wrote:
A friend with a new state of the art super high tech electronic dash
computer controlled washer claims it is best to power the beast thru a
surge suppressor.

If a washer needs protection, then so does every household item including clocks, RCD, furnace, recharging phones, and the most critical item during a surge - smoke detectors. Nothing adjacent to an appliance claims to protect from destructive surges. Protection means a surge is connected to earth BEFORE it enters a building. No way around that well proven science.

Does not matter if AC service is overhead or underground. Risk from surges (lightning and other sources) remains.

Sure it remains. But it does matter. With an underground service, the
lines leading from the street to the house, the masthead, etc are not
present and can't be hit by a direct lightning strike. Less target is
better than more target.



Even underground wires can carry a direct lightning strike into a building. Every wire in every incoming cable must connect to single point earth ground BEFORE entering. Otherwise a surge is inside hunting for earth destructively via appliances. Earth ground (not a protector) is the most critical component in every protection 'system'.

What does an adjacent protector do? MOVs might connect that surge from hot wire to neutral or safety ground wires. Now that surge has even more paths to find earth ground destructively via a washer or other nearby appliance. Adjacent protectors can even make damage easier if a 'whole house' solution is not implemented.


You can listen to Tom or you can read what the electrical engineers that
specialize in surge protection say at IEEE and NIST. Both groups say
that point-of-use surge protectors do work, endorse them as part of a tiered
approach and standalone too.

http://www.nist.gov/pml/div684/upload/Surges_happen.pdf

http://www.lightningsafety.com/nlsi_lhm/IEEE_Guide.pdf



All appliances contain robust protection.

Not as robust as the protection in a quality plug-in surge protector.



Your concern is a rare transient that might occur once every seven years. That transient must be connected low impedance (ie less than 3 meters) to earth BEFORE entering. Otherwise it will go hunting for earth destructively via appliances. Nothing adjacent to an appliance claims to 'block' or 'absorb' that transient. If anything needs that protection, then everything needs that protection.

Plug-ins/point-of-use work by clamping all the inputs to the same level.


I'm sure the usual W Tom rant will be forthcoming.