Vaisala AWS310 Instruction Manual

Improving Weather Station Grounding
You can improve the grounding of Vaisala weather stations to make the weather station less
susceptible to damages caused by lightning.
While visiting the site, check also that the enclosure and sensor cables have been grounded according
to the instructions.
For more detailed information on grounding, see Grounding and Lightning Protection in Vaisala
Outdoor Installations Technical Reference.
More Information
‣Improving Grounding of Stainless Steel Flanges (page 2)
‣Improving Grounding of Rubber Flanges (page 5)
‣Checking Weather Station Grounding (page 6)
M212202EN-A
Technical Note Improving Weather Station Grounding
AWS310, AWS310‑SITE, AWS430, FOC201, RME111
PUBLISHED BY
Vaisala Oyj
Vanha Nurmijärventie 21
FI-01670 Vantaa, Finland
Phone:[phone]
© Vaisala 2018
All rights reserved. Any logos and/or product names are trademarks of Vaisala or its individual partners.
Any reproduction, transfer, distribution or storage of information contained in this document is strictly
prohibited. All specifications — technical included — are subject to change without notice.

Improving Grounding of Stainless Steel Flanges
•Serrated lock washer A8.4 DIN6798 (8 pcs)
•Torque wrench (1 … 5 Nm)
1. Loosen the screws (4 pcs) that hold the flange at the bottom of the enclosure until you can
remove the counter ribs inside the enclosure .
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2. Push the screws back to place and insert the serrated lock washers on the screws.
3. Insert the counter ribs on the screws.
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4. Tighten all the screws lightly one by one.
5. Tighten all the screws to 4 Nm.
6. Repeat the procedure on the second flange of the enclosure.
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Improving Grounding of Rubber Flanges
Torque wrench (1 … 5 Nm)
1. Check that the screws with which the rubber flange is attached to the bottom of the enclosure
are tightened to 2.6 ...3.0 Nm.
2. Tighten the screws if needed.
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Checking Weather Station Grounding
While visiting the site, check also that the enclosure and the sensor cables are properly grounded.
More Information
‣Checking Enclosure Grounding (page 6)
‣Checking Sensor Cabling and Grounding (page 8)
Checking Enclosure Grounding
1. Check that the enclosure grounding cable is connected to the system grounding point.
2
3
4
1
1Cable lug with hole Ø 6.2 mm (0.24 in)
2System grounding point
3AC (mains) cable
4Enclosure grounding cable
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2. Check that the other end of the enclosure grounding cable is connected to a grounded location
such as grounding connector.
1
2
3
4
1System grounding point
2Enclosure grounding cable
3Grounding connector
4Grounding cables
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3. Check that the grounding cables have not been pulled too tight.
Keep the curve of the down conductor smooth with a minimum radius of the bent
cable 20 cm (8 in) and never over 90° angles.
CAUTION!
Checking Sensor Cabling and Grounding
If you need to shorten sensor cables, you need:
•Cable cutters
•Cable stripper
•Crimping tool
•Pipette (rubber flange only)
•Ferrules
•Shrinkable tubes or electrical tape
Make sure that you prepare or connect only de-energized wires.WARNING!
To avoid strain on the connector, make sure you connect the cable properly. Too much
strain may cause the cable to fall o, damage the cable or connector, or make the cable or connector
susceptible to water leakage.
CAUTION!
Do not damage or change the wiring. Incorrect wiring can cause damage and prevent or
limit operation.
CAUTION!
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1. Check that the sensor cables have been cut to a suitable length. The cables must not be looped.
A long cable between units (sensors, transmitters, power supplies, and displays)
can cause a lethal lightning-induced current surge.
WARNING!
If the cables are too long:
a. Cut the cable to proper length.
b. If the weather station has rubber flanges, insert the pipette through one of the feed-through
rondels in the flange and pull the cable through.
If the weather station has stainless steel flanges, strip the cables first.
c. Strip the cable to expose the wires.
~300 [~12]
~15 [0.59]
mm
[in]
1 2 3 4 5
1Ferrule
2Unused wires covered with a shrinkable tube or electrical tape
3Wire
4Cable shield folded over cable sheath
5Cable
d. Connect the cables again. For grounding instructions, see step 2 or step 3. For the wiring
diagram, see the installation manual.
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2. In weather stations with stainless steel flanges, check that the sensor cable shields have been
grounded to the cable glands.
• In cable glands with EMC springs, the cable shield must be firmly connected to the EMC
spring.
1
2
1Cable gland
2EMC spring
• In cable glands without EMC springs, the cable shield must be grounded to the cable gland
using a sealing insert.
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3. In weather stations with rubber flanges, check that the sensor cable shields have been grounded
to the grounding rail.
4. Check that all unused wires have been isolated with a shrinkable tube or electric tape.
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