30 CFR § 75.517-2
Plans for insulation of existing bare power wires and cables.
(a) On or before December 31, 1970, plans for the insulation of
existing bare power wires and cables installed prior to March 30, 1970, shall
be filed with the District Manager of the Coal Mine Safety District in which
the mine is located to permit approval and prompt implementation of such
plans.
(b) The appropriate District Manager shall notify the operator in
writing of the approval of a proposed insulation plan. If revisions are
required for approval, the changes required will be specified.
(c) An insulation plan shall include the following information:
(c)(1) Name and address of the company, the mine and the
responsible officials;
(c)(2) Map or diagram indicating location of power wires and
cables required to be insulated;
(c)(3) Total length of bare power wires and cables required
to be insulated;
(c)(4) Schedule for the replacement or insulation of bare
power wires and cables;
(c)(5) Type of insulation to be used and the voltage rating
as indicated by the manufacturer.
(d) The District Manager shall be guided by the following criteria in
approving insulation plans on a mine-by-mine basis. Insulation not conforming
to these criteria may be approved provided the operator can satisfy the Mine
Safety and Health Administration that the insulation will provide no less
than the same measure of protection.
(d)(1) Insulation shall be adequate for the applied voltage
of the circuit.
(d)(2) When tubing is used to insulate existing power wires
and cables, it shall have a dielectric strength at least equal to the voltage
of the circuit. When the tubing is split for purposes of installation, the
joints shall be effectively sealed. The butt ends may be sealed with a
moisture resistant insulating tape.
(d)(3) When tape is used to insulate existing power wires and
cables, it shall be applied half-lapped and one thickness of the tape shall
have a dielectric strength at least equal to the voltage of the circuit. The
tape shall be self-adhesive and moisture resistant.