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Show activity. The rodent problem can be controlled by uM- ig metal-sheathed cable, which is also an advantage for electrical shielding. Marmots in particular have a voracious appetite for electrical insulation. For this reason no cable should be exposed above ground-- it must be run through metal conduit and into metal junction boxes. For a standard analog wind installation, the recommended cable is three- pair, 19 gage, direct- burial cable with 10 mil copper sheath ( cost around 20<; per foot). This can be ordered from local electrical supply houses. Electrical cables should never be placed on the surface of the ground, for snow creep and glide invariably will break them. If it is necessary to run buried cables over exposed outcrops of bedrock, they must be placed inside heavy metal conduit and the conduit securely fastened with expansion bolts or cement grout to the rock. In zones of the large snow creep pressures, the greater strength of regular water pipe instead of conduit may be preferred. Joints in pipe or conduit should be securely fastened with proper couplings. Federal agencies often will be able to acquire high- quality cable through Federal surplus lists. Any cable so acquired should be checked carefully to be sure it in fact meets the requirements for direct burial usage and will provide the required reliable service. Expert advice should be sought in evaluating such cable before acquisition is made, and then the cable should be checked on receipt to ascertain whether it is the same cable specified in the surplus- property order. Many such " free" cables are not suitable for the exacting requirements of a reliable mountain installation and are no economy in the long run. Never use surplus Army field phone wire or cable for these installations. This kind of wire is admirable for the purpose intended, namely one- time use in combat, but is not designed for long life as direct- burial cable. This advice is based on much hard experience. All cables should be properly terminated in junction boxes. If the termination is exposed to the weather, the junction boxes should be weatherproof. There are so many different kinds of iunction boxes available, and so many different requirements, that we will make no specific recommendations here. Consult a reliable electrical supplies dealer for recommendations for specific installations. it is not enough to brinq a cable into a junction box and terminate it in a rat's nest of taped splices. The cable should connect to a terminal board, one wire to a terminal. The type of terminal called " barrier terminal strip" is recommended. See Figure 1 * » for an example of a properly installed junction box with terminals. A typical wind telemetry installation will have a buried cable terminated at the upper end by a junction box mounted on kk |
