In , on 07/17/03
at 06:26 PM, (Foo Man Choo SE) said:

[ ... ]

There are proper ways to deal with incoming power, and services from the
outside to your home. Proper procedures must be implemented for proper
grounding and isolation where applicable.


Good point - I'll have to get more than one electrician's opinion on
this. I have heard that many so called "qualified" electricians do
not implement proper grounding to deal with nearby lighting. We moved
into our home about seven months ago and it passed electrical
inspection without a hitch. Also, the cable and telephone
installation guys, who presumably need to hook up their lines to the
common ground, did not mention the potential for problems. I did
notice that all were connected to the main grounding rod. Maybe it's
an issue with the size or type of grounding rod used.

If you need a really good ground, they have to be maintained and
checked from time to time. If the soil near the ground rod dries out,
the "ground" won't be very effective.

The cable and phone installers in your area are either better than
average or know something about your local situation. In my urban area
none of the phone drops are grounded or protected against lightning and
most of the cable TV guys are too busy (or stupid) to ground anything.

Check out your area. Some areas have a history of regular, severe
lightning strikes. If this is true for your area, you need *GOOD*
professional advice.

Anyone with any recommendations on whole house protection systems?
I've heard that Home Depot and Lowe's carry such systems (I believe
Siemens makes one) but are they good enough. Do I look at the joules
rating or what?


Did you enquire to your neighbours to see if they also have the same
problems? If you are having major appliances damaged, especially heavy
ones such as stoves, toasters, refrigerators, and ect, this is a very
serious power safety problem and should be looked after. Heavy
appliances are more difficult to damage by having power and lightning
surges, than sensitive electronic equipment.

Yes, our next door neighbors also lost their A/C and at least two
others lost their phone connections. Don't know about other damage.

Expand your inquiry. It is possible that there is a power distribution
problem on or near your block. You can register your concern with the
local utility, but they usually don't pay too much attention to a
single complaint. In one case there was a TV interference problem that
covered several blocks. Clearly it was associated with the power line,
but it took months to convince the utility company to send out its
diagnostic truck. Finally, after a phone-in campaign was organized, the
utility came out, found, and fixed the problem.

If your ground is not so good, surge suppressors don't work well. Also,
cheap surge suppressors are a complete waste of time because they offer
little protection.

The MOV based surge suppressors, while very effective, generally fail
"open" (the device stops "eating" the surges and begins passing them
through). Unfortunately, unless they are obviously burned, there is no
practical way to test MOV's in the field. Cheap designs force the MOV
to deal with the full brunt of the surge. MOV's can deal with one "big
one" and thousands of smaller surges. It is always possible that the
day after you install the cheap suppressor, that big will come along,
the MOV will sacrifice itself to protect your equipment, and die. Good
designs use other methods to remove the gross surge energy, leaving the
MOV to safely deal the the remainder.

If you have frequent power outages consider installing a "lockout"
device. In many cases a series of surges is generated when the power is
turned on again that are larger and more dangerous than the one
generated by the original distant event. The lockout device will
disconnect your delicate equipment from the power line if power is
interrupted. You can wait and reset the lockout device manually after
the situation has stabilized.

If you have long runs of telephone, computer network, or speaker wire
inside your house and you live in a severe lightning area, you'll need
to re-think things because a nearby strike that can be completely
stopped at your service entrance, can still induce a damaging transient
directly into a long run of wire. (sorry, I can't be precise about how
long is "long")

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