Transients exist in two varieties - differential and common
mode. (Difference between spike and surge is nonsense probably
invented by some naive technical writer.)  Common mode are
typically source of hardware damage.  That means surge
protection - earth ground - must be installed appropriately.
Therein lies the value of 'whole house' protectors.  Not only
are they properly sized to protect from all surges AND remain
fully functional for the next surge.  But they also earth
common mode surges which plug-in protectors do not even claim.

  That APC demonstrates but another problem with plug-in
protectors - undersized.  It was so grossly undersized as to
be destroyed by a transients that was not even sufficient to
damage adjacent computer. Transient appeared equally -
electrically arrived at the same time - to both computer and
surge protector.  Computer power supplies must withstand at
lest 1000 volt transients.  However since a plug-in surge
protector is not doing anything effective, then why bother
installing sufficient joules inside.  Too few joules is why
that surge protector failed before the transient finished.  It
was undersized since it really is not providing serious surge
protection.

  But when undersized, the naive think the surge protector
failed to save a computer.  Bull.  Surge not even sufficient
to damage computer was too much for an undersized (maybe 400
joules) surge protector.

  Joules determines the life expectancy of a surge protector.
Quality of earth ground determines a surge protectors
effectiveness.  That means even the connection to earth ground
must be short - less than 10 feet - and single point earthing
must be the building's best ground.

  The idea of 220 volts tangled with 110 is nonsense.  110
volts is the 220 volts.  'Whole house' surge protectors are so
inexpensive that renting one at $5 per month from the utility
is extremely profitable for the utility.  But and again, even
that is only as effective as earth ground which is provided by
the building owner - not by utility.

  Earthing is so critical that it is surge protection.  A
surge protector is not surge protection.  A surge protector
only shunts (connects, diverts) a surge to surge protection -
central earth ground.  Surge protectors do not stop, block, or
absorb surges.  They only shunt - meaning that they can even
contribute to appliance damage if not connected less than 10
feet to central earth ground.  If not provided something to
shunt to, then a surge protector may simply shunt the surge to
earth ground through the computer - resulting in a famous
modem error message "No Dialtone Detected".

  "Whole house' surge protector maybe cost about $1 per
protected appliance verse maybe $20 or $50 per for ineffective
plug-in protectors.  Also 'whole house' starts at or should
exceed 1000 joules - so as to not be damaged by surges.
Details of the overall concept were discussed in two threads
in the newsgroup misc.rural:
   Storm and Lightning damage in the country   28 Jul 2002
   Lightning Nightmares!!   10 Aug 2002



John Lee wrote:
> FWIW, the lineman yesterday told me that often times the hot wire will
> touch the ground wire during a short, sending current through the
> ground, which is death to the device because surge protectors only
> monitor the hot side.  Any electrical engineers out there?
>
> John Lee
>
> At 01:46 PM 4/23/03 -0400, Brice Yokem wrote:
>> My understanding is there is a difference between spikes and surges.
>>
>>TINAPO
>>
>> A power spike is a brief increase in voltage which can cause cumulative
>> damage to electronic equipment but not to more mundane devices like
>> electric motors, transformers or heating elements.
>>
>> A power surge is an increase in current which can cause overloading
>> of components which is death on electronic components and can
>> gradually ruin the more mundane devices, especially electric motors.
>>
>> A surge protector does not protect against spikes and a spike
>> protector does not provide much protection against surges.
>>
>> Some power companies (the one in OK does) provides protection for
>> about $5 per month and will replace or repair any device which is
>> damaged by either type.
>>
>> As far as what happened to Mr Brandt.  Probably one of the 220v
>> wires got tangled up with a 110v wire and ended up putting 220v
>> current in the 100v outlets for one circuit in the house at the
>> expense of the other 110v circuit.

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