Electrical Damage – Common Causes & Recommended Prevention
Electrical damage can be caused by many different factors. Below are some of the more common causes and
some suggested methods of minimizing potential problems.
Common Causes:
Storm Activity –
lightening in your area can do damage to your instruments in different ways. The obvious
way is due to a direct or nearby strike. In addition, lightening storms, dust storms, dry snowstorms and
strong dry winds can all cause static electricity to build up on and around your external sensors. Regardless
of the cause this built up electricity can discharge itself through the cable connecting the external sensors to
the instrument.
Power Surges –
A surge may come from the electric company’s switching generators or power grids, from
local industries or after power interruption when accumulated power suddenly surges back through AC lines.
Even the on-and-off switching of large electrical appliances, such as refrigerators or clothes dryers can
create damaging fluctuations. This is especially true with sensitive weather recording devices.
Yourself –
Are you constantly giving and/or receiving a shock every time you touch a doorknob or another
person? If so you have a great deal of static electricity in your environment. Depending on where you live,
static electricity may be a year round problem or only a seasonal problem. In either case, it is possible for a
person to carry enough of a charge to damage an instrument.
Recommended Prevention:
Ground Your Mounting Mast – IMPORTANT
: PVC and fiberglass are not recommended mast materials as
they can store high amounts of static electricity within themselves. It is recommended that you follow the
grounding instructions that came with your mounting mast, while also maintaining accordance to your local
Electric Code. In the absence of instructions for your mast system, the following generic guidelines from the
National Electric Code
may be helpful.
1) The NEC requires that the antenna mast and mount be grounded directly. No splices or connections are
allowed in the ground wire between the mast and the ground rod.
2) Attach one end of a No. 8 (or thicker) copper or aluminum ground wire to the antenna mast.
Note:
As static
electricity issues are more common for weather sensors than direct lightening strikes, consider installing the
ground wire as physically close to the wind sensors as possible to best combat static electricity issues. For
multi-piece (or telescoping) masts, consider connecting the ground to each separate section of the mast.
3) For painted or coated masts, scrape off the coating around the area where the contact will be made. This
will ensure a good, solid connection. (Once the ground is attached to the mast, any scraped off portion that
is exposed should be recoated with paint or other sealant.)
4) Next, run the ground wire to ground as directly as possible. Standard wire staples can be used to secure the
ground wire against the side of the house. Avoid making 90° or sharper turns with the ground wire. A
lightning charge has difficulty making such a turn and therefore may discharge into the house. Make ground
wire bends as smooth and as gradual as possible.
5) The ground wire must be connected to a ground rod. Water pipes or plumbing fixtures are not acceptable.
A good copper-coated steel ground rod driven at least 3 feet into the ground is required. Special clamps that
provide a solid connection between the ground wire and ground rod should be used
Use Surge Protectors –
For the AC adapter, a UL 1449 rated surge protector with EMI/RFI filtering is
recommended. This rating will be clearly listed on the packaging of any good quality surge protector.
Discharge Yourself –
If the instruments are located in an environment where static electricity is a problem,
make sure that you discharge yourself before touching the instrument(s). The shock that you get from
touching a doorknob or another person can often be sufficient to damage an instrumen
t.
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