connectors. Required cable lengths are determined during design and supplied ready to install. Some estimate that modular cables reduce onsite installation time by 60% to 70% while improving the reliability of the electrical connections. The special case of cable glands Cable connectors called glands are used wherever cables pass through an enclosure. Glands serve three purposes — securing the cable, preventing cable wear, and providing a seal around that cable to shield components inside the enclosure from environmental debris. The way in which cable glands secure the cable essentially prevents damage to electrical contacts from yanking or other disturbances. It also prevents the cable from scraping or rubbing against the sharp sheet- metal edge of the enclosure cutout. That’s important because sheet metal can easily saw through cable sheaths and eventually cause the cable cores to short. Less demanding applications often use lamellar glands having multiple fingers that clamp around the cable. This type of gland is less costly but requires regular retightening to maintain
ingress protection. Higher quality glands use a continuous seal that clamps around the cable. This type of gland is much less likely to loosen over time.
Construction of today’s industrial-power connectors Devices used for industrial automation often require a wired power supply in addition to a data connection. The relatively new technology of PoE mentioned earlier is preferable where it’s possible to use because it keeps cabling so simple. However, the vast majority of automation components and systems require traditional power cords.
Figure 6: General-purpose power cables include a variety of IEC and other standard connectors. (Image source: Getty Images)
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