402.8
458 "
220.
.0155
0....
.32495
319.6
385 "
185.
.0196
1....
.2893
253.4
308 "
156.
.0247
2
.25763
201.0
249 "
131.
.0311
3....
.22942
159.3
201 "
110.
.0392
4....
.20431
126.4
163 "
92.3
.0495
5....
.18194
100.2
133 "
77.6
.0624
6....
.16202
79.46
109 "
65.2
.0787
7....
.14428
63.01
90 "
54.8
.0992
8....
.12849
49.98
74 "
46.1
.125
9....
.11443
39.64
62 "
38.7
.158
10....
.10189
31.43
52 "
32.5
.199
11....
.090742
24.93
43 "
27.3
.251
12....
.080808
19.77
36 "
23.
.316
13....
.071961
15.68
30 "
19.3
.399
14 ....
.064084
12.43
25 "
16.2
.503
15....
.057068
9.86
21 "
13.6
.634
16....
.05082
7.82
18 "
11.5
.799
17....
.045257
6.20
15 "
9.6
1.088
18....
.040303
4.92
13 "
8.1
1.271
TABLE OF DIMENSIONS, WEIGHT AND RESISTANCE OF BARE COPPER WIRE.
BROWN & SHARPE'S GAUGE THE STANDARD.
American Gauge, I
Brown & Sharpe's
Number.
Diameter, Mils.
AKEA.
WEIGHT AND LENGTH,
sp. gr. 8.9.
RESISTANCE AT 75 F.
Circular
mils. (d2)
1 mil. =
.001 in.
Square in.
(d2 x .7854)
Lbs. per
1,000 ft.
Lbs. per
mile.
Feet
per Ib.
R
Ohms
per
1,000 feet.
Ohms
per mile.
Feet
per Ohm.
Ohms per Ib.
OOCO
too
00
460 000
409.640
364.800
211600.00
167805 01
133079.40
166190.
131790.
! 104520.
639.33
507.01
402.09
1 3375.7
2677.0
2123.0
1.56
1 97
2.49
.04906
.06186
.07801
.25903
.32664
.41187
20383.
16165.
12820.
.000076736
.00012039
.00019423
1
o
324 950
289 300
257.630
105592.50
83(194 2
66373.0
82932.
65733.
52130.
319.04
252.88
200.54
1684 5
1335.2
1058.8
3.13
3.95
4.99
.09831
.12404
.15640
.51909
.65490
.82582
10409.
8062.3
6393 7
.00030772
.00048994
.00078045
3
4
5
229.420
204 310
181.910
52634 00
41742.00
33102.00
41339
32784.
25998.
159.03
126.12
100.01
839.68
665 91
528.05
6.29
7.93
10.00
.19723
.24869
.31361
1.0414
1.3131
1.6558
5070.2
41)21.0
3188.7
.0012406
.0019721
.0031361
6
7
8
12 020
144.2SO
128 400
26250.50
20816.00
16509. 01)
20617.
16349.
12966.
79 32
62.90
49.88
418.81
332 11
263.37
12.61
15.90
20.05
.39:>46
.49871
.62881
2.08S1
2.6331
3.3201
2528.7
2003.2
1590.3
.0049868
.0079294
.012608
9
10
11
114.430
101.890
90.742
13594.00
10381.00
8234.00
10-284.
8153.2
6467.0
39.56
31.37
24.88
208 88
165.63
137.37
25.28
31.38
40.20
.79281
1.
1.2607
4 1860
5.2800
6.6568
1261.3
1000.0
793.18
.020042
.031380
.050682
12
13
14
80.808
71.961
64.084
6529 90
5178.40
4106.80
5128.6
4067.1
3146.9
19.73
15.65
12.41
104.18
82.632
65.525
50.69
63.91
80.59
1.5898
2.0047
2.5908
8.3940
10.585
13.680
629.02
498 83
385.97
.080585
12841
.20880
15
16
17
57.068
50.820
45.257
3256.7
2582.9
2048.2
2557.8
2028.6
1608.6
9.84
7.81
6.19
51.956
41 237
32.683
101.63
128.14
161.59
3.1150
4 0191
5.0683
16.477
21 221
26.761
321 02
248.81
197.30
.31658
.51501
.81900
18
19
20
21
22
23
40.303
35.390
31.961
1624.3
1252.4
1021.5
1275.7
983.64
802.28
4.91
3.78
3 09
25.925
20 051
16.315
203.76
264.26
324.00
6 S911
8.2889
10.163
33.745
43.765
53.658
156.47
120.64
98.401
1.3023
2.1904
3.2926
28.462
25.347
22.571
810.10
642.70
509.45
636.25
504.78
400 12
2.45
1.94
1.54
12 936
10 243
8.1312
408.56
515 15
649 66
12.815
16.152
20.377
67.660
85.283
107.59
78.037
61.911
49.087
5 2355
8 3208
13.238
24
25
26
20.100
17.900
15.940
404.01
320 40
254.01
317 31
251 64
199.50
1.22
.97
.77
6.4416
5.1216
4.0656
819.21
1032.96
1302.61
25.695
32 400
40.868
135.67
171 07
215.79
38.918
30 864
24.469
21.050
33.466
35.235
27
28
29
14.195
12.641
11.257
201 50
159.79
126.72
158 26
125.50
99.526
.61
.48
.38
3.2208
2.5344
2.0064
1642.55
2071 22
2611.82
51.519
64.966
81.921
272 02
343.02
432.54
19.410
15.393
12.207
84.644
134.56
213.96
30
81
32
10.025
8.928
7.950
100.5
79.71
63.20
78.933
62.604
49.637
.30
.24
.19
1.5840
1.2672
1.0032
3293.97
4152 22
5236.66
103.30
127.27
164.26
545.39
871.69
867.27
9. 6812
7.8573
6.0880
340.25
528.45
860.33
33
34
35
7.0SO
6 304
5.614
50.13
39.74
31.52
39 372
31 212
24.756
.15
.12
.10
.7920
.63:56
.5280
6602.71
8328.30
10501.35
207.08
261.23
329 35
1093.4
1379.3
1738.9
4 8290
3 8281
3.0363
1367.3
2175.5
3458.5
36
37
38
5.000
4.453
3.965
25.00
19 83
15.72
19.635
15.567
12.347
.08
.06
.05
.4224
.3168
.2640
13238.83
16691.06
20834.65
415.24
523 76
66U.67
2192 5
2765.5
3486.7
2.4082
1.9093
1.5143
5497.4
8742.1
13772.
39
40
3.531
3.144
12.47
9. 89
9.7939
7.7676
.04
.03
.2112
.1584
26302 23
33175.94
832.48
1049.7
4395 5
5342.1
1.2012
.9527
21896.
34823.
RULES AND REGULATIONS
Or THE NEW ENGLAND INSURANCE EXCHANGE AND BOSTON FIRE
UNDERWRITERS' UNION FOR ELECTRIC LIGHTING. [ADOPTED
APRIL 15TH, 1889, AND SUPERSEDING ALL PREVIOUS RULES.]
ARC SYSTEM.
OUTSIDE WIRES.
All outside overhead wires must be covered with some material of high
insulating power, not easily abraded ; they must be firmly secured to properly
insulated and substantially built supports. All tie wires must have an
insulation equal to that of the conducting wires.
2. All joints must be so made that a perfectly secure and unvarying
connection, fully equal to the cross-section of the conducting wire, will be
secured and they should be soldered. Resin should not be used as a flux.
Nothing but an acid solution should be used, and any excess should be washed
off before the splice is covered. This also applies to inside wires. All joints
must be securely wrapped with an approved tape.
The following formula for soldering fluid is recommended, viz. :
Saturated solution of zinc 5 parts.
Alcohol 5 "
Glvcerine 1
/
3. Care must be taken that conducting wires are not placed in such
position that it would be easy for water, or any liquid, to form cross connection,
between them, and they should not approach each other nearer than one foot.
(86)
PRACTICAL DYNAMO BUILDING. 87
4. The wires must never be allowed in contact with any substance
other than air, and their proper insulating supports.
5. Conducting wires carried over or attached to buildings, must be at
least seven feet above the highest point of flat roofs, and one foot above the
ridge of pitch roofs. Lines constructed subsequent to the adoption of these
regulations should not be run over and attached to buildings other than those in
O < - >
which the light or power is being, or is to be used, but should be on separate
poles, or structures, where they can be easily reached for inspection.
6. When they are in proximity to other conducting wires, or any
substance likely to divert any portion of the current, dead, insulated guard-irons
must be placed so as to prevent any possibility of contact in case of accident to
the wires, or their supports. The same precautions must be taken where sharp
angles occur in the line wires, and also where any wires (telegraph, telephone
or others) could possibly, owing to their position, come in contact with the
electric light wires.
7. Overhead wires from the main circuit or pole in the street to the
terminal insulators attached to buildings, and at the point where they enter a
building, must not be less than twelve inches apart. They must be rigidly
and neatly run, and supported by glass or porcelain insulators, or rubber
hooks. The rubber hooks must be of an approved pattern, i. e., with
the rubber insulation free from flaws, and projecting over the hook in cup
form.
8. Service blocks must be protected by at least two coats of water-proof
paint over their entire surface ; and when used to support rubber hooks, must
have at least one inch of wood between the inner end of the hook and the back
of the block.
9. For entering buildings, wires with an extra heavy water-proof
insulation must be used from the terminal insulators outside to the inside of a
building. They must loop down, so that water may drip off, without entering
the building, and the holes through which they enter should, where possible,
slant upward. If an approved glass insulator for bushing the hole be used, the
extra heavy water-proof insulation will not be required.
10. Service wires must come in contact with nothing save air, and their
88 PRACTICAL DYNAMO BUILDING.
insulating supports, except in unavoidable cases, when a wire with an extra
heavy insulation suitable for the purpose must be used.
11. The use of porcelain knobs, as insulators, except in perfectly dry
places, or for the support of specially insulated wire, will not be accepted unless
of some approved .shape.
12. ]S"one but an approved tubing will be accepted as a durable
water-proof insulation.
13. Wires must enter and leave the building through an approved
cut-out switch.
14. The cut-out switch must be " double contact," and should
effectually close the main circuit, and cut off the ulterior when turned " off."
It must be so constructed that there shall be no arc between the points when
thrown "on" or " off." It should be automatic in its action in either
direction, not stopping between points when once started. It should indicate
upon inspection whether current be "on" or " off."
15. It must be mounted on a non-conducting base, kept free from
moisture, and easy of access to firemen and police.
INSIDE WIRING.
16. Wires must not be concealed ; they must be run in plain sight so as
to be open to inspection at any time. They should be kept apart at least
twelve inches.
17. In perfectly dry places wires may be supported by cleats of wood
(filled to prevent the absorption of moisture) or porcelain. Cleats should be so
made as to separate the wire at least one-fourth of an inch from the building.
18. In places liable to dampness, wires must be separated at least one
and one-half inches, they must be thoroughly and carefully put up, and
supported upon porcelain or glass insulators, or hard rubber hooks. They
should also be provided with an approved insulation covering.
19. When wires pass through walls, floors, partitions, etc., in-doors,
glass insulators, or an extra covering of hard rubber, should be used. Wires
must never be left exposed to disturbance or mechanical injury.
PRACTICAL DYNAMO BUILDING.
ARC LAMPS.
20. The frames and other exposed parts of arc lamps must be carefully
insulated from the circuit.
21. Each lamp must be provided with a proper hand switch, and also
with an automatic switch that will shunt the current around the carbons, should
they fail to feed properly.
22. Stops of some kind must be provided to prevent the carbons from
falling- out in case their clamps fail to hold them ; and these stops must always
be in place when the lamp is burning.
23. For inside use the light must be surrounded by a globe resting in a
tight stand, so that no particles of melted copper or heated carbon can escape.
When inflammable material is near or under the lamp, the globe must be
protected by a wire netting. Unless a very high globe, which closes in as far
as possible at the top, be used, it must be provided with some protector or spark
arrester, reaching to a safe distance above the light. Broken or cracked globes
must be replaced by perfect ones immediately. (By inflammable material is
meant such as dry goods, clothing, millinery and the like in stores ; flyings or
goods in fabric factories, shavings and saw-dust in w r ood- working shops, or any
other substance that can be readily ignited by droppings or flyings from the
lamp.)
24. Electrical connection between the conducting wires and lamps must
be made through a suitable "hanger-board" and rods on which the lamp is
hung.
INCANDESCENT LAMPS ON ARC-LIGHT CIRCUITS.
25. The rules for running wires for arc lamps apply also to incandescent
lamps run in series.
26. These must be provided with a proper hand switch, and also with
an approved automatic device which will shunt the circuit around the carbon
filament should it break. ~No electro-magnet device will be accepted for this
purpose.
27. Any method of distributing current to incandescent lamps on
90 PRACTICAL DYNAMO BUILDING.
arc-light circuits, other than as above provided for, must receive the approval
of this Exchange before being put into use.
DYNAMOS AND MOTORS.
28. They must be located in dry places, not exposed to the flyings of
combustible material, and must be insulated upon dry wood, filled to prevent
absorption of moisture. They must be kept thoroughly clean and dry. They
must be provided with a reliable automatic regulating device, or a competent
person must be in attendance near the machine whenever it is in operation. In
wiring for motive power, the same precautions should be taken as with a
current of the same volume and potential for lighting.
29. The wires leading to motors should be separated at least twelve
inches from each other, and must be provided with an approved cut-out switch
at the point where they enter the building. The same precautions must be
observed in entering the building that are required for lighting circuits.
TESTING.
30. All circuits should be tested at least twice a day with a suitable
magneto, or other approved device, in order to discover any escapes to ground
that may exist. One test should be made in the morning, and another in
ample time before starting, to remove any defect, should it be found to exist.
The rules for testing should be observed in any separate or isolated plant the
same as in Central Stations.
31. The JSTew England Insurance Exchange reserves the right at any
time to add to, change or modify these rules, and to enforce such modifications,
changes, etc., as it shall deem necessary for safety; and it will use all
reasonable efforts to promptly notify all electric light companies of any change.
32. The signing of these rules by an electric light company, or persons
controlling electric lights, shall be considered a guaranty on their part that
they will have the testing performed on their circuits or lines as above required.
INCANDESCENT SYSTEM.
OUTSIDE WIRES.
1. All outside overhead wires must be covered with some material of
high insulating power, not easily abraded, and they must be firmly secured to
properly insulated and substantially built supports. All the wires must have
an insulation equal to that of the conducting wires.
2. All joints must be so made that a perfectly secure and unvarying
connection, fully equal to the cross-section of the conducting wire, will be
secured and they should be soldered. All joints must be securely wrapped
with an approved tape.
3. Care must be taken that conducting wires are not placed in such
position that it would be easy for water, or any liquid, to form cross connection
between them, and main conductors or feeders should not approach each other
nearer than one foot.
4. The wires must never be allowed in contact with any substance other
than air, and their proper insulating supports.
5. Conducting wires carried over or attached to buildings, must be at
least seven feet above the highest point of flat roofs, and one foot above the
ridge of pitch roofs. Lines constructed subsequent to the adoption of these
regulations should not be run over and attached to buildings other than those
in which the light or power is being, or is to be, used, but should Jbe on
separate poles, or structures, where they can be easily reached for inspection.
G. When they are in proximity to other conducting wires, or any
substance likely to divert any portion of the current, dead, insulated guard- irons
must be placed so as to prevent any possibility of contact in case of accident to
the wires or their supports. The same precautions must be taken where sharp
(91)
92 PRACTICAL DYNAMO BUILDING.
angles occur in the line wires, and also where any wires (telegraph, telephone,
or others) could possibly, owing to their position, come in contact with the
electric light wires.
7. Wires from main circuit to main cut-out inside of buildings, must be
separated by a distance of not less than six inches, for currents having an
electro-motive force of 250 volts or less, and this distance must be increased for
currents of higher potential.
8. They must also be rigidly and neatly run, and must be supported by
glass or porcelain insulators, or by rubber hooks. Rubber hooks must be of
an approved pattern; i. e., with the rubber insulation free from flaws, and
projecting over the hook in cup form.
9. Service blocks must be protected by at least two coats of water-proof
paint over their entire surface ; and, when used to support rubber hooks, must
have at least one inch of wood between the inner end of the hook and the back
of the block.
10. For entering buildings, wires of extra heavy and durable
water-proof insulation, protected by an outside covering not easily abraded,
must be used from the terminal insulator outside, to the main cut-out inside of
the building. They must loop down, so that water may drip off without
entering the building, and the holes through which they enter should, where
possible, slant upward. If an approved glass insulator for bushing the holes be
used the extra heavy insulation will not be required.
11. Service wires must come in contact with nothing save air, and their
insulating supports, except in unavoidable cases, when a wire with an extra
heavy insulation, suitable for the purpose, must be used.
12. The use of porcelain knobs as insulators, except in perfectly dry
places, or for the support of a specially insulated wire, will not be accepted,
unless of some approved shape.
TTNDERGROUND SERVICE.
13. Where underground service conductors, enclosed in a metal tube,
enter a building, special care must be taken at the point where the conductors
leave the tube, and thence to the main cut-out, to protect them in such a
PRACTICAL DYNAMO BUILDING. 93
manner that they can not come in contact with each other, nor with the tube,
nor be acted upon by falling moisture, nor disturbed by anything being moved
against them, etc.
14. This service must not end in any place where it would be unsafe or
undesirable to place a cut-out, but should be continued by means of specially
insulated conductors (and a space of ten inches should be maintained between
them) to a suitable location.
INSIDE WIRING.
15. Copper wire used for incandescent lighting must be procured from
manufacturers whose products have been found, by reliable tests, to be at least
95 per cent, conductivity. Samples of wire to be used, or in actual use, must
be submitted to this Exchange, for tests of conductivity, at any time when
required. Samples of wire must also be submitted for tests of insulation, at
any time when required.
For inside work, no wires smaller than "No. 16 " B. & S." or ISTo. 18
"B. W. G." will be approved.
16. Permission will not be granted for the use of the lights unless the
wire come fully up to the standard of conductivity, no matter how well the
wiring may be done.
17. All parties, firms or corporations proposing to do construction work
or wiring, either outside or inside, must fully satisfy this Exchange of their
ability to do the work in a safe and acceptable manner.
18. Before using any new form of insulation, the approval of this
Exchange for its use under the proposed circumstances must be secured.
19. The use of lead-covered wire, or wire the covering of which
contains paraffine, is prohibited.
20. Mouldings with open grooves laid against the walls or ceilings will
not be approved. A wood moulding having a backing of at least one-fourth
inch thickness to intervene between the wire and the wall or ceiling of the
building, the backing to be protected by at least two coats of water-proof
paint, and the moulding of such shape as to protect the wire from moisture,
will be approved.
94 PRACTICAL DYNAMO BUILDING.
21. When wires are run in new buildings, and are to be concealed from
view by walls and ceilings, care must be taken to separate them ten inches or
more, whenever it be possible to do so, by running them singly on separate
timbers, studding, etc. Cleats are not desirable for concealed work. All
concealed wires should be supported on insulators, such as porcelain knobs, or
other equally good, non-combustible, insulating substance. Wires should,
where it be possible, be kept from contact with any part of the building by
means of such insulators, rather than to depend upon the insulation covering.
Where complete separation from the building by air space and insulators be
not possible, an approved insulation covering, that shall be water-proof
and non-combustible, will be required. Wires run in non-combustible and
water-proof tubes, made of a suitable insulating material, will be approved.
Care must be taken to keep the wires away from metal pipes and other
conductors. Outlet wires should be left in such a way as not to be injured by
plasterers. They should not, as a rule, be brought through the same opening
with gas-pipes, but must be carefully insulated from them.
22. Approval will not be given to any work where the wires have been
" fished" any great distance.
23. Moulding must not be used in wet places.
24. In dye-houses, paper and pulp mills, and other buildings specially
liable to moisture, all wires (except when used for pendants) must be separated
at least six inches. The wire must be thoroughly and carefully put up, and
must be supported by glass or porcelain insulators, or by rubber hooks.
25. In crossing any metal pipes, or any other conductor, wires must be
separated from the same by an air space of at least one-half inch, where
possible, and so arranged that they can not come in contact with each other by
accident. Wires should go over water-pipes where possible.
26. Where wires pass through partitions, floors, etc., glass insulators,
or an outer covering of hard rubber should be used to protect them.
27. Wires must never be left exposed to mechanical injury, or to
disturbance of any kind.
28. Metallic staples must never be used ; when staples are used they
must be of an approved insulating material.
PRACTICAL DYNAMO BUILDING. 95
29. None but an approved tubing will be accepted as a durable
water-proof insulation.
30. Wires of the same polarity, but belonging to different circuits, or
leading to and from a double-pole switch, must not run in one groove through
the same tube, nor in the same slot in a cleat.
31. Cleats should be made of well-seasoned hardwood (filled to prevent
the absorption of moisture), porcelain or other approved material, and so made
as to separate the wire at least one-fourth inch from the building. When,
secured by cleats not over four feet apart and tightly stretched in the same
horizontal plane, wires having a difference of potential of 120 volts or less,
should be separated at leaet one and one-half inches ; when they are confined
in moulding a half-inch space is sufficient. This rule applies only to small
mains, taps, etc., mains carrying currents of large volume should be separated a
greater distance.
32. The dividing strip between grooves in moulding must never be
reduced below one-half inch in thickness by cutting out to admit ioints in
wires.
33. Where exposed to acid fumes, vapors of ammonia, etc., wires
should be provided with an insulation that will not be injured thereby, and
should be put up in the manner described in Rule 24.
34. All splices in wires must be soldered ; a soldering-bolt should be
used for this purpose, if possible. Care must be taken not to render the wire
brittle by over-heating. Resin should not be used as a flux. Nothing but an
acid solution should be used, and any excess should be washed off before the
splice is covered.
35. The insulation of any joint must be equal to that of the other parts
of the same wire.