The Saint Paul globe. (St. Paul, Minn.) 1896-1905, 1901-08-30

ventilated to the outdoor air if posi-
bic, through a chimney or fiue. There
Should be at least six inches air space
on all sides of the transformer.
81. Car Houses
a. Must have the trolly wires securely
supported on insulating hangers.
b. Must have the trolley hangers
placed at such distance apart that in
case of a break in the trolley wire, con-
tact cannot be made with the floor
at a proper place outside of the building
SO that all trolley circuits can be cut
out at one point, and line of circuit
breakers must be Installed so that when
TINS cut-out switch is open the trolley
wire Will be dead at all points within one
hundred feet of the building. The cur
rent must be cut out Of the building
whenever the same is not in use or the
road not in operation.
d. Must have all lamps and stationary
motors installed in sucn a way that one
main switch can control the whole of
each installation lighting or power. in
dependently of main feeder switch No
portable incandescent lamps or twin wire
altoWed, except that portable ineandes-
cent lamps may be used in the pits; con-
nections to be made by two approved
rubber-covered flexible wires (see No.
3S) properly protected against mechanical
: injury; the circuit to be controlled by
switch placed outside of the pit.
e. Must have all wiring apparatus in,
stalled in accordance with rules under
C. for constant-potential systems.
T. Must not have any system of feeder
distribution ceritering in the building.
g. Must have the rails bonded at each
joint with not less than No 2 B, & S.
annealed copper wire; also a supplement.
tary wire to be run for each track.
h. Must not have cars left with trolley
in electrical connection with trolley wire.
81. Lighting and Power From
Railway Wires
a. Must not be permitted under any
pretenSe in the same circuit with trolley
wires with ground return, except in
electrical railway cars, electric car houses
and their power stations, nor shall the
same dynamo be used for both purposes.
33. Series Lamps
a. No system of multiple-series or Sc
ries- multiple for light or power will be
allowed.
b. Under no circumstances can lamps
be attached to gas fixtures
Sec. 256. Extra High Potential sys-
TENS
Over $500 Volts.
Any circuit attached TO any machine or
combinations of machines, which devel-
on a difference of potential between any
two wires or over $500 volts, shall be
considered as an extra hig4l-potentlal cir
cult, and as coming under that class, un-
less an approved transforming device is
used, which cuts the difference of poten-
tial down to $500 volts or less.
"a. Primary wires
a. Must not be brought into or over
buildings except power and sub-stations.
SO. Secondary wires
a. Must be installed under rule for
high potential systems when their imme-
date primary wires carry current at a
potential Of over thirty-ive hundred
volts, unless the primary wires are en-
tirely underground.
Sec. 257. Fittings, Materials and
Details of Constructions
All Systems and Voltages. Insulated
Wires:
SO. General Rules
a. Copper for insulated conductors
must never vary in diameter SO as to DE
more than two one-thousandtns of an
inch less than the specified size.
81. Rubber Covered
a. Copper for conductors must be thor
opghy timed. Insulation for Vo- yes be-
tween 0 and 600.
b. Must be Of rubber CT other approved
substance, and be of a thickness not less
than TN! /, that given in the following table
From is to 16 inclusive, 1-32-inch
From 1t to Inclusive, 3-64-inch
From to inclusive, 1-16-inch
F,om l to 0OGO inclusive, 5-64-inch
From OO0O to 5C000O c. M, 3-32-inch
F'rom50O100 to 100000 C. NJ 7-64-inch
Larger than 100000 C. NJ. 1-S-inch
| Measurements of insulating walls are to
be made at the thincst portion of the
dielectris.
c. The completed coverings must show
| an insulation resistance of at least 1t0
megohms per mile during thirty days
immersion in water at seventy degrees
Fahrenheit.
d. Each foot of the completed covering
must show a dielectric strength suffi-
Gent to resist throughout five minutes
the application OF an electro,motiYe force
of 3C00 volts per one sixty-foGrth Of an
inch thickness of insulation under the
following conditions:
The source of alternating electro-motive
force shall be q transformer of at least
/ one kilowatt capacity. The application
of the electro-motiYe force shall first be
made at 1900 volts for five minutes and
then the voltage increased by steps of not
oyer $40 vclts, each held for five minutes
until the rupture of the Insulation oc
ours. The tests for dielectric strength
Shall be made of sample of wire which
has been immersed for Y hours in water
one foot of which is submerged in a cen
Quoting liquid held in a metal trough.
one of the transformer terminals being
connected to the copper of the wire and
the other to the metal of the trough
Insulation for VOItages Between
600 and $500.
e, The thickness of the insulation
walls must not be less than those
given in the following table for B. e.
S. gauge. sizes:
From IA to l, inclusive 3-32 inch.
From to $4,000 c. M, 1892, covered by
a tape or a braid
Larger than 100000 c. NJ. 4-32, covered
by a tape or braid.
+. The requirements as to insulation
and breakdown resistance for wires for
lowpotential systems shall apply with
the exception that an insulation resist
ance of not less than 800 megohms per
mile shall be required.
Insulation for Voltage over $500.
g. Wire for arc light circuits exceed
ing $500 volts potential snail have an in
Sulating wall not less than six-thirty-
seconds of an inch in thickness, and
shall withstand a breakdown test of at
least thirty thousand volts and have
an insulation of nat least 500 megohms
per mile.
The tests on this wire to be made un-
der the same conditions as for Iow-po-
tential wires.
h. All of the above installations must
be protected by substantial braided
covering, properly saturated with a pre-
serVatiVe compound, and sufficiently
strong to Withstand all the abrasion
likely to be met with in practice, and
sufficiently elastic to permit all wires
smaller than No. g. & S. gauge to be
bent around cylinder with twice the
diameter of the wire without injury to
the braid.
3S. SIow-Burning Weather-PrOOf-
a. The insulation shall consist of two
coatings, the inner one to be fire proof in
character, the outer to be weather proof
The inner fire-proof coating must COM
prise at least siX-tenths of the total
thickness of the wall The complete