A wire also absorbs some power when it shorts a large
current. Does that mean the purpose of a wire is to absorb
electricity? Of course not. MOVs are not installed to absorb
power. But then if one first consults manufacturer
datasheets, then that becomes woefully obvious.

http://www.nteinc.com/Web_pgs/MOV.html
Let's use the 2V130 as example. This device will shunt up to
4500 amps during the standard 8/20 usec surge. A 1000 volt
transient at 4500 amps would be well over 600 joules. But
this device is only rated at 39 joules maximum. How can that
be? Because MOVs, like wire, are not installed to absorb the
energy. They are designed to shunt.

If an MOV was absorbing the transient, then MOV voltage must
increase as more energy is absorbed. That means more voltage
confronts the adjacent appliance. But MOVs don't work that
way. If their purpose was to absorb a transient, then they
must connect in series with the appliance. But MOVs connect
in parallel - a shunt mode device. To be effective as shunt
mode devices (like wire), the MOV must conduct massive
transients and absorb less of that transient. That is what
MOVs do. They shunt. They do not stop, block, absorb, or
filter a transient. They operate like a wire during the
transient. They shunt.

As previously demonstrated from manufacturer datasheets (and
not from wild speculation about what 'joules' measures): If
that MOV in a plug-in protector that can only withstand 3
standard 8/20 microsecond transient, then the larger 'whole
house' protector (that costs about same) will withstand about
300+ such surges. Joules is a measure of MOV life
expectancy. MOVs are not designed to absorb a transient -
which is in direct contradiction to what many web sites,
written by English majors, will claim. The better an MOV,
then the more energy it can shunt - per joule. Read
manufacturer datasheets; not web sites written by English
majors. It is the difference between fact and fiction.

Now for your insults - which apparently are due to
insufficient electrical knowledge. First learn before
insulting others. There is a datasheet. Read it before
posting. Keep it civil - if you can. Posted previously are
accurate electrical engineering facts taken from manufacture
datasheets. Any protector that is damaged by the first surge
is grossly undersized - an ineffective protector usually sold
to those who like to throw money at urban myths.

BTW, MOV degradation is not due to power absorption. It is
due to energy absorption - a major technical difference that
English majors will not understand.

Telamon wrote:
In article , w_tom
wrote:

Any protector that is damaged by the first surge is grossly
undersized. No effective surge protector can be damaged. They
are not sacrificial devices as urban myth purveyors will claim.

The characteristics of MOV's are well known. Every time a MOV turns
on due to the device threshold being exceeded they degrade based
on how much power is absorbed.

If you are whom I think you are the facts won't bother you one bit
and further nonsense posts can be expected.