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Knowledge Base

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

  1. Turn off modem and disconnect modem cables from bulkhead connector.

  2. Remove bulkhead connector.

  3. 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).

  4. Slide shrink tube over the antenna cable end. (Alternatively, use self-sticking rubber tape or other weatherproof sealant when finished.)

  5. Connect antenna cable and the modem’s pigtail to the EMP protector.

  6. Slide shrink tube over the area where the antenna cable and EMP Protector meet, covering the EMP Protector and the antenna cable end completely.

  7. 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
  • Protects all 9 wires
  • Connectors: DB9 (M) and DB9 (F)
  • Clamp Voltage: 18V

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
  • Type: Silicon Oxide Varistor
  • Clamp Voltage: 100V
  • Max. System Voltage: 48VDC Nom.
  • Max. Current: 50,000 Amps
  • Max. Energy: 750 Joules
  • Number of Surges: Unlimited
  • Response time: Clamps 10,000 Amps in 10 ns
  • Common Mode and Differential Protection
  • For negative, positive and floating ground systems

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)
  • Signals Protected: Two, Tip & Ring
  • Stages of Protection: 3, including gas tubes, avalanche diodes and MOV thyristors
  • Maximum Output Voltage: 180 Volts
  • Power Per Signal: 500 Watts
  • Reaction Time: Less than 5 ns
  • Line Connectors: RJ-11
  • Ground Connector: #4 screw
  • Mounting: Screw
  • Size: 4.5"W (114mm) x 1.8"D (46mm) x 1.5"H (38mm)
  • Environment: 0oC to 50oC, 0% to 95% RH.

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

Power Monitoring Software

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Comments (1)
Comment by Felipe G. Nievinski on Wed, Apr 16th, 2014 at 5:49 PM
Any info specific to ethernet ports would be appreciated. Do you guys normally use a surge protector / lightning arrester for indoor Internet connection? Thanks for the great resource.
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Last modified: Monday, 12-May-2014 00:18:29 UTC