Note the voltage on that fuse. No matter how fast it is, if a
transient exceeds that voltage, then the fuse remains a conductor.
Furthermore, destructive transients occur in microseconds. That fuse
takes tens of milliseconds to open. Two reasons - both numbers - that
demonstrate why one cannot stop or block destructive transients.

Meanwhile, the phone line should already have a protector installed
for free that looks something like boxes at:
http://www.alarmsuperstore.com/bw/bw%20connectors.htm
But again, the protector is not protection. A protector is simply a
connection to earth. If that box is not properly earthed, then a
transient will seek earth ground, destructively, via household
appliances.

Most destructive transients enter on AC main seeking earth ground.
Incoming on AC electric, into telephone appliances such as portable
phone base station, fax machine, computer modem - or that intercom.
Then outgoing to earth ground via telephone line. To have damage,
first, a path to earth ground must be both incoming and outgoing
through damaged electronics. Incoming on that intercom AC electric;
outgoing via phone line. It also explains why some appliances are
damaged while others are not.

But again, what is the protection? Earth ground. Fuses, power strip
protectors, and anything else that will 'stop or absorb' a surge is
myth. Ben Franklin demonstrated the solution in 1752. Give a
transient a better (shorter, low impedance, etc) path to earth so that
it need not find a path, destructively, via electronics.

Those fuses only might blow. And if they did, maybe 300 consecutive
and separate transients could have already damaged the electronics.
More often, fuses trip due to and after damage created by a destructive
transient. If one suffers damage, one discovers why the dwelling was
not properly earthed. Why was lightning seeking earth ground inside a
building? The answer is often directly traceable to human failure.
Protection is about earthing before a transient enters the building.

Dr.Ace wrote:
Hi Bob,
I'm Ace - WH2T.
Here's my story.
So far I have been very lucky. Neighbors closest on my north and south sides
have both been hit, BAD SEVERE strikes. We live on a hill.
I had a strike take out a cheap portable TV that was in the kitchen and it
blew a fuse in a VCR. It also came in the telephone line and blew up some FM
intercoms that were connected to the telephone line. After that happened I
had a commercial lightning arrestor installed by my electric power company
at the electric meter.

I use 2 HF antennas, a 272 ft delta loop and a 160 meter band 1/4 wave
inverted L antenna, both antennas go thru my MFJ-989C Tuner . When I am not
on the air I leave the antenna switch on the tuner in the "Dummy Load"
position. That connects a 300 watt 50 ohm resistor to the radio's antenna
jack and grounds both antennas.

The main lightning problems I have had in the 12 years at this QTH are
surges coming in the telephone line.
I noticed when I moved here that all the telephone jacks in the house were
black. I lost 9 computer modems in short order. I installed the smallest
fast blow fuses I could find in both sides of the telephone line (they are
under 100 ma) . The next time there was a nearby strike it blew both fuses
and still blew my computer modem.
After that I installed three 130 Volt MOVs outside the house in the
telephone box , one across the telephone line and one from each side of the
telephone line to ground. I also installed a very small pigtail neon lamp
between or across the 2 sides of the telephone line. It acts as a gas tube
type of arrestor, and lights when the telephone rings, or when lightning
strikes nearby; the threshold to fire is under 100 volts. I also installed a
DPDT knife switch , to break the telephone line when the computer is not
connected to the internet. No further problems. I live out in the country
dial up is all that is available here other than expensive satellite access.
Anyway , now on to your question.
...