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Power - Surge and Lightning Protection
Surge and Lightning Protection
Electro-magnetic-pulses (EMP) originate from lightning strikes (LEMP) or from nuclear explosions (NEMP). These fast rising electrical fields induce high voltage pulses in unprotected coaxial cables, antennas, data communication cables, or power cables from where they can be directly transmitted to the input of electronic equipment.
Lightning protection is essential for permanent station implementation, and proper system grounding is essential for any lightning protection to work. UNAVCO provides a grounding terminal in its enclosure design that, when connected to an 8 foot grounding rod, provides protection for permanent station equipment.
N-type Surge Arrestor
UNAVCO recommends replacing standard bulkhead connectors for modems (radio or celluar) with protected connectors on all permanent station enclosures. This in-line lightning protection helps isolate the equipment in the enclosure by shunting power surges to ground. Proper system grounding is essential for this protection to work.
UNAVCO has tested EMP protectors for use with GPS antenna cables to ensure data quality. See the Effects of LEMP Protection on GPS Signals test report for [dated] detailed information.
The following table lists the items needed to replace a single bulkhead connector.
| Items | Manufacturer/Vendor | Part No. | Specifications |
|---|---|---|---|
|
EMP Protector Surge Arrestor (N-type) |
HUBER+SUHNER, Inc. One Allen Martin Dr. P.O. Box 400 Essex, VT 05451 (802) 878-0555 |
3402.17.K |
See table below. |
|
Surge Arrestor Capsule (gas filled) |
HUBER+SUHNER, Inc. One Allen Martin Dr. P.O. Box 400 Essex, VT 05451 (802) 878-0555 |
73 Z-0-0-48 | |
|
6" of Encapsulating Shrink Tube |
Alpha / Newark Electronics (800) 463-9275 |
FIT-750-1-1/2 (1.5" dim) |
The following table shows the bulkhead connector specifications. To see an image enlarged, right-click and select ’View Image.’
| Series 3402.17.K EMP Protector | Surge Arrestor Capsule (for use with 3402.17.K EMP Protector) |
 |
 |
| Definitions for the Surge Arrester Capsule table specs | Outline Drawing of the 3402.17.K EMP Protector in mm |
 |
 |
| Mounting Hole Dimensions in mm | |
 |
Note: Mounted properly the surge arrester capsule will be up.
Installation Instructions
Grounded Enclosure
Turn off modem and disconnect modem cables from bulkhead connector.
Remove bulkhead connector.
Insert EMP protecter with nut on the inside of the enclosure (make sure that the star washer makes good contact, i.e., electrical continuity, with the enclosure).
Slide shrink tube over the antenna cable end. (Alternatively, use self-sticking rubber tape or other weatherproof sealant when finished.)
Connect antenna cable and the modem’s pigtail to the EMP protector.
Slide shrink tube over the area where the antenna cable and EMP Protector meet, covering the EMP Protector and the antenna cable end completely.
Heat the shrink tube to seal (encapsulate) the connection.
Non-Grounded Enclosure
See installation diagram:
Serial Port Protectors
UNAVCO recommends using surge protection for RS232 data connections to protect / isolate equipment from power fluctuations, spikes, induced transient and other surges, or nearby lightning strikes.
The following table lists the recommended item needed to protect data connections.
| Items | Manufacturer/Vendor | Part No. | Specifications |
|---|---|---|---|
| RS232 Surge Protector |
Black Box Corporation P.O. Box 12800 Pittsburgh, PA 15241 (800) 552-6816 |
SP361A-R2 |
|
Solar Array Protection
UNAVCO recommends using low voltage-high current DC lightning arrestors to protect/isolate solar powered equipment from nearby lightning strikes.
The following table lists the recommended item needed to protect solar powered equipment.
| Items | Manufacturer/Vendor | Part No. | Specifications |
|---|---|---|---|
| DC Lightning Arrestor |
RMS Electric Inc. 2560 28th Street Boulder, CO 80301 Donna |
LA 302 DC |
|
Phone Line / Telecommunications
UNAVCO recommends using lightning sponges to protect/isolate telecommunication equipment from nearby lightning strikes.
The following table lists the recommended item needed to protect telecommunications equipment.
| Items | Manufacturer/Vendor | Part No. | Specifications |
|---|---|---|---|
| Lightning Sponge |
Telebyte Technology, Inc 270 Pulaski Road Greenlawn, NY 11740 1-800-835-3298 |
22PX (discontinued) |
|
AC Power Surge Protection
UNAVCO uses the following Uninteruptable Power Supplies at Permanent GPS Stations
Back UPS Pro 280 - United States
Part No. 30723 - Manufacturer APC - Mfr. Part No. BP280S - Price: $110.00
Back-UPS Pro 280 (discontinued)
International Back UPS Pro 280
Vendor: PC Mall - Part No. 801098 - Manufacturer APC - Mfr. Part No. BP280SI - Price: $153.99
International Back UPS Pro 280