1382

LAWS OF MARYLAND

Ch. 418

provided with means to drain or confine the oil if a rupture
of the transformer casing occurs.

(c)  A permanent or portable transformer for use
underground shall be either air cooled or nonflammable
liquid cooled, if ordered after June 1, 1949.

(d)  An underground station containing a transformer
filled with flammable oil shall be provided with doorsills,
or their equivalent, to confine the oil if leakage or
explosion occurs.]

[7-431.

Every six months the operator of a coal mine, in which
any electric system exists, shall make an "electric system
map" of the mine. The electric system shall be shown in the
detail and the manner the bureau prescribes by
distinguishing colors and signs on an exact reproduction of
the mine map required pursuant to § 7-401. Identical copies
of the electric system map shall be kept in the office of
the foreman at the mine and filed with the district mine
inspector for his official use.]

[7-432.

At every mine where electricity is used for power, a
competent mine electrician shall be employed. He shall have
full charge of the electric apparatus and system in and
about the mine. However, he is subject to the authority of
the official in charge of the mine.]

[7-433.

A DANGER -- HIGH VOLTAGE sign shall be posted
conspicuously on each transformer enclosure, high-potential
switchboard, and other high-potential installation.]

[7-434.

(a)  Each surface and underground substation and any
room housing a switchboard shall be kept free of refuse.
Metal containers shall be provided for oily waste.

(b)  Any switchboard shall be located so that ample
room is provided between the switchboard and passageway or
other lane of travel. It shall have an entrance at each end
to permit an authorized person to inspect, adjust, or repair
apparatus behind the board. The entrance to the rear of each
switchboard shall be guarded to prevent access by any
unauthorized person, unless the switchboard is located in a
locked building.

(c)  Any switchboard shall be well-lighted for switch
operations in the front and for repair and maintenance in
the rear.