Εικόνες σελίδας
PDF
Ηλεκτρ. έκδοση

powerful currents are used, must be made of some incombustible substances that will withstand the heat of the arc when the switch is changed.

Motors.-Wires for motors should be run exactly as for lamps on similar circuits.

On low-tension circuits, where motors are run in multiple, safety catches must be used on each side of the circuit.

On high-tension circuits the same restrictions apply as for arc lamps, and suitable cut-outs must be provided.

Motors must be treated as dynamos as regards insulation, flyings, dampness, etc.

NOTE.-If the regulations of the Underwriters' Association are not followed in wiring buildings, the wiring is liable to be condemned by the Insurance Inspectors and the policy canceled.

WIRE TABLES.

WEIGHT OF UNDERWRITERS' LINE WIRE, INSULATED.

[graphic]

EQUIVALENT SECTIONAL AREA OF WIRES, B. & S. GAUGE.

[blocks in formation]
[blocks in formation]

64-16
64-17 1 and 3
64-18 2 and 3

3 and 5 4 and 6 5 and 7 6 and 8 7 and 9 8 and 10 9 and 11 10 and 12 11 and 13 12 and 14 13 and 15 14 and 16 15 and 17 16 and 18

[blocks in formation]

The above table indicates the number of smaller wires required to give a sectional area equal to one larger size wire, the figures between the horizontal lines corresponding to each other. For example: It requires two wires, No. 0, or 4 wires, No. 3, etc., to give a sectional area equal to 1 wire, No. 0000. Again; it requires two wires, No. 13, or 4 wires, No. 16; or 2 wires, 1 No. 12 plus 1 No. 14, to give a sectional area equal to 1 No. 19.

COMPARATIVE SIZES OF WIRES, B. & S. AND BIRMINGHAM

GAUGES.

[graphic][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][ocr errors][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed]

COMPARATIVE SIZES OF WIRES, B. & S. AND BIRMINGHAM

GAUGES-(Continued).

[graphic][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed]

NOTE.-B. & S. gauge is generally used in America.

[blocks in formation]
[blocks in formation]

.39528 .49845 .62849 .79242 .99948

2,529.90 2,006.20 1,591.10 1,262.00 1,000.50

.00497280 .00790780 .01257190 .01998530 .03170460

.05054130 .08036410 .12778800 .20318000 .32307900

7 8 9 10

2.08706
2.63184
3.31843
4.18400
5.27726

11 12 13 14 15

1.26020
1.58900
2.00370
2.52660
3.18600

6.65357
8.39001
10.57980
13.34050
16.82230

793.56 629.32 499.06 395.79 313.87

16 17 18 19 20

4.01760
5.06600
6.38800
8.05550
10.15840

21.21300
26.74850
33.72850
42.53290
53.63620

248.90
197.39
156.54
124.14
98.44

.51373700 .81683900 1.29876400 2.06531200 3.28437400

« ΠροηγούμενηΣυνέχεια »