392.6.Installation. (E) Multiconductor Cables Rated 600 Volts or Less.
Cables containing 300 or 600 volt insulated conductors may be installed intermingled in the same cable tray which is different from the requirements for raceways. This is a reasonable arrangement because a person may safely touch a 300 or 600 volt cable which is in good condition, so having the cables come into contact with each other is not a problem either. Many cable tray users separate the instrumentation cables from the power and control cables by installing them in separate cable trays or by installing barriers in the cable trays. Often, because of the volume of the instrumentation cable, using separate cable trays is the most desirable installation practice.
Numerous cable tray systems have been installed where the instrumentation cables and branch circuit cables are installed in the same cable trays with and without barriers with excellent performance and reliability. Most problems that occur involving instrumentation circuits are due to improper grounding practices. For analog and digital instrumentation circuits, good quality twisted pair Type ITC and Type PLTC cables with a cable shield and a shield drain wire should be used. Do not purchase this type of cable on price alone, it should be purchased because of it's high quality. Engineers specifying cables should be knowledgeable of the cable's technical details in order to design systems which will provide trouble free operation.
No. 2: Where separated with a fixed solid barrier of a material compatible with the cable tray.
| Fixed Solid Barrier | Cables Rated |
300 & 600 | ||
Volt Cables | Comparable Material | Over 600 Volts |
|
|
|
NO. 2
392.6.Installation. (G) Through Partitions and Walls.
Whether penetrating fire rated walls with tray cable only or cable tray and tray cable, the designer should review with the local building inspector the method he proposes to use to maintain the fire rating integrity of the wall at the penetration. Many methods for sealing fire wall penetrations are available, including bag or pillow, caulk, cementitious, foam, putty and mechanical barrier systems.
Many designers prefer to run only the tray cable through fire rated walls. Sealing around the cables is easier than sealing around the cables and the cable tray. Also, should the cable tray or its supports become damaged, the tray will not exert forces which could damage the wall or the penetration.
392.6.Installation. (F) Cables Over 600
Volts.
Cables with insulation rated 600 volts or less may be installed with cables rated over 600 volts if either of the following provisions are met.
No. 1: Where the cables over 600 volts are Type MC.
300 & 600 | Cables Rated Over |
Volt Cables | 600 Volts Are Type MC |
NO. 1
Cooper B-Line, Inc
392.6.Installation. (H) Exposed and Accessible.
Article 100 - Definitions.
Exposed: (as applied to wiring methods) on or attached to the surface or behind panels designed to allow access.
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