Section 126.34 - Cable in Conduit Systems(1)General. On systems operating above 2 KV to ground, the design of the conductors or cables installed in non-metallic conduit should consider the need for an effectively grounded shield and/or sheath.(2)Installation.(a)General. 1. Bending during handling, installation and operation shall be controlled to avoid damage to any of the components of the supply cable.2. Pulling tensions and side-wall pressures of cable should be limited to avoid damage to the supply cable. Manufacturer's recommendations may be used as a guide.3. Ducts should be cleaned of foreign material which could damage the supply cable during pulling operations.4. Cable lubricants shall not be detrimental to cable or conduit systems.5. On slopes or vertical runs, consideration-should be given to restraining cables to prevent downhill movement.6. Supply, control, and communication cables shall not be installed in the same duct unless the cables are maintained or operated by the same utility.(b)Cable in Manholes and Vaults -- Supports. 1. Cable supports shall be designed to withstand both live and static loading and should be compatible with the environment.2. Supports shall be provided to maintain specified separation between cables.3. Horizontal runs of supply cables shall be supported at least three inches above the floor, or be suitably protected. Exception: 220 CMR 126.34(2)(b) does not apply to grounding or bonding conductors.
4. The installation should allow cable movement without destructive concentration of stresses. The cable should remain on supports during operation.(c)Cable in Manholes and Vaults -- Separation. 1. Adequate working space shall be provided in accordance with 220 CMR 126.32(4)(b).2. Between supply and communication facilities (cable and/or equipment): Where cable and/or equipment is to be installed in a joint use manhole or vault, it shall be done only with the concurrence of all parties concerned.
Supply and communication cables should be racked from separate walls. Crossings should be avoided.
Where supply and communication cables must be racked from the same wall, the supply cables should be racked below the communication cables.
Supply and communication facilities shall be installed to permit access to either without moving the other.
Clearances shall be maintained as specified in 220 CMR 126.34: Table 1.
Table 1
Minimum Separation Between Supply and Communications Facilities in Joint Use Manholes and Vaults
Phase-to-Phase Supply Voltage | Inches of Separation (Surface to Surface) |
0, to 15,000 | 6 |
15,001 to 50,000 | 9 |
Exception 1: These separations do not apply to grounding conductors.
Exception 2: These separations may be reduced by mutual agreement between the parties concerned when suitable barriers or guards are installed.
(d)Identification of Cables in Manholes and Vaults. 1. Cables shall be permanently identified by tags or otherwise at each manhole or other access opening of the conduit system. Exception: 220 CMR 126.34(2)(d) i. does not apply where the position of a cable, in conjunction with diagrams or maps supplied to workmen, or other means give sufficient identification.
2. All identification shall be of a corrosion-resistant material suitable for the environment.3. All identification shall be of such quality and located so as to be readable with auxiliary lighting.4. Where cables in a manhole are maintained or operated by different utilities or are of supply and communication usage, they shall be permanently marked as to company and/or type of use.(3)Grounding and Bonding. (a) Insulation shielding of cable and joints shall be effectively grounded.(b) Cable sheaths or shields which are connected to a ground at a manhole shall be bonded or connected to a common ground.(c) Bonding and grounding leads shall be of a corrosion-resistant material suitable for the environment or suitably protected.(4)Fire-proofing. Although fire-proofing is not a requirement, it may be provided in accordance with each utility's normal service reliability practice to provide protection from external fire.(5)Communication Cables Containing Special Supply Circuits. Special circuits operating at voltages in excess of 400 volts to ground and used for supplying power solely to communications equipment may be included in communications cables under the following conditions: (a) Such cables shall have a conductive sheath or shield which shall be effectively grounded and each such circuit shall be carried on conductors which are individually enclosed with an effectively grounded shield.(b) All circuits in such cables shall be owned or operated by one party and shall be maintained only by qualified personnel.(c) Supply circuits included in such cables shall be enclosed in an effectively grounded shield or shields and shall be terminated at points accessible only to qualified employees.(d) Communications circuits brought out of such cables, if they do not terminate in a repeater station or terminal office, shall be protected or arranged so that, in the event of a failure within the cable, the voltage on the communications circuit will not exceed 400 volts to ground.(e) Terminal apparatus for the power supply shall be so arranged that live parts are inaccessible when such supply circuits are energized.(f) Such cables shall be identified and the identification shall meet the pertinent requirements of 220 CMR 126.34(2)(d). Exception: The requirements of 220 CMR 126.34(5) do not apply to supply circuits of 550 volts or less which carry power not in excess of 3200 watts.