Plug-in protectors are cheap? Hardly. They cost typically tens of
times more money per protected appliance. Since they are missing that
short and dedicated earthing wire, then plug-in protectors may even
provide a surge with more destructive paths through an adjacent
appliance.
We traced path of a surge that damaged networked and powered off
computers. Confirmed that path by replacing ICs on the board and
restoring all machines. A protector does not stop, block, or absorb
surges. It is called a shunt mode device. It shunts - either to earth
ground or into adjacent appliances. They simply distribute a surge to
all other wires. If one of those wires is not the short connection to
earth, then a protector may shunt that surge to earth via a protector.
Effective protectors make the 'less than 10 foot' connection to
earth. Protector earths transients that would otherwise overwhelm
protection already inside appliances. Any protection that would be
effective on that computer power cord is already inside the computer.
Protection that remains effective if transients are not permitted
inside the building.
They are called 'whole house' protectors. Sold in Home Depot, Lowes,
and electronics supply houses are effective products from Square D,
Siemens, Cutler-Hammer, Intermatic, Leviton, and GE. Not mentioned are
products sold in Radio Shack, Walmart, Sears, Staples, Circuit City,
Kmart, or Best Buy. Effective protectors have that dedicated earthing
wire to connect protector to protection. Protection is the most
critical component in any protection system: earth ground. Just
another reason why the home earthing may need be upgraded to post 1990
National Electrical Code requirements.
So where in those numerical specs does the plug-in manufacturer even
list each type of transient AND provide numbers for that protection.
Notice no mention of protection in their numerical specs. And one
would call that cheap? Yes. So cheap to enrich its manufacturer and
yet provide no effective protection. It don't hurt the manufacturer.
And it also don't claim to provide that protection. Listed is
effective protection that costs less money. Defined are ineffective
plug-in protectors with hyped names and yet don't even claim to provide
protection in their numerical specs.
Insurance with a plug-in protector? You wish. Review details in its
warranty. Chock full of exemptions. One even implied that if a surge
protector in the building was not manufactured by them, then warranty
is void. The list of exemptions like this are numerous. Warranty on a
protector only exists when one forgots to read details.
Effective protector makes a 'less than 10 foot' connection to earth.
Every homeowner should consider this many times less expensive and so
effective solution.
Meanwhile none of this is about low or high voltage. Transients
(volts of 10 or 100 times higher) that occur in microseconds have
little relationship to voltages that make minor changes in seconds or
milliseconds. Solutions to high or low voltages (140 to 90) involve
other solutions; other devices. Low voltages must never damage
electronics. Appliances must also withstand high voltages such as 140,
170, and 400 without damage depending on time.
Before discussing voltage irregularities, first define each with
numbers - voltage and time. A surge protector complete ignores when
120 volts climbs to 200 volts. See its box. Let-through voltage is
maybe 330 volts.