(b) Other Articles. The requirements of this part shall be additional
to, or amendatory of, those prescribed in Articles 1.0 through 4.90 of
this Code. Special attention shall be paid to Article 2.50.
(c) Protection Against Physical Damage. Conductors and cables in
tunnels shall be located above the tunnel floor and so placed or
guarded to protect them from physical damage.
1.10.4.2 Overcurrent Protection. Motor-operated equipment shall be
protected from overcurrent in accordance with Parts 4.30.3, 4.30.4,
and 4.30.5. Transformers shall be protected from overcurrent in
accordance with 4.50.1.3.
1.10.4.3 Conductors. High-voltage conductors in tunnels shall be
installed in metal conduit or other metal raceway, Type MC cable, or
other approved multiconductor cable. Multiconductor portable cable
shall be permitted to supply mobile equipment.
1.10.4.4 Bonding and Equipment Grounding Conductors.
(a) Grounded and Bonded. All non–current-carrying metal parts of
electric equipment and all metal raceways and cable sheaths shall be
effectively grounded and bonded to all metal pipes and rails at the
portal and at intervals not exceeding 300 m throughout the tunnel.
(b) Equipment Grounding Conductors. An equipment grounding
conductor shall be run with circuit conductors inside the metal
raceway or inside the multiconductor cable jacket. The equipment
grounding conductor shall be permitted to be insulated or bare.