1062 LAWS OB^ MARYLAND. [CH. 437

ELECTRICITY

110. Surface Transmission Lines. Overhead high-poten-
tial power lines shall be placed at least 15 feet above the
ground and 20 feet above driveways and haulageways,
shall be installed on insulators, and shall be supported and
guarded to prevent contact with other circuits.

Overhead power circuits shall be protected against light-
ning and voltage surges, and high-potential power lines
shall be protected adequately by circuit breakers, fuses, or
both.

Electric wiring in surface buildings shall be installed
so as to present minimum fire and contact hazards.

111. Transformer Stations, (a) Unless surface trans-
formers are isolated by elevation (8 feet or more above
the ground), they shall be enclosed in a transformer house
or surrounded by a suitable fence at least 6 feet high. If
the enclosure is of metal, it shall be grounded effectively.
The gate or door to the enclosure shall be kept locked at
all times, unless authorized persons are present.

(b) Surface transformers containing flammable oil and
installed where they present a fire hazard (near mine
openings or in or near combustible buildings) shall be pro-
vided with means to drain or to confine the oil in event of
rupture of the transformer casing.

(c) Transformers ordered after the effective date of
this Act, both permanent and portable, for use underground
shall be air-cooled or non-flammable-liquid cooled.

(d) Underground stations containing transformers fill-
ed with flammable oil shall be provided with door sills, or
their equivalent, that will confine the oil if leakage or ex-
plosion occurs.

114. DANGER—HIGH VOLTAGE signs shall be posted
conspicuously on all transformer enclosures, high-potential
switchboards, and other high-potential installations.

115. Substations and Switchboards, (a) Surface and
underground substations shall be kept free from refuse,
and metal containers shall be provided for oily waste.

(b) Switchboards installed after the effective date of
this Act shall be located so that ample room will be pro-
vided between the switchboard and passageways or lanes
of travel and shall have an entrance at each end to permit
authorized persons to inspect, adjust, or repair apparatus