New Zealand Gazette – 1935 – No. 65

Page 2569

✨ Electrical Standards Tables



SEPT. 6.] THE NEW ZEALAND GAZETTE. 2569

TABLE IX.—INSULATION RESISTANCE OF CABLES.

Number and Diameter (Inches) of Wires comprising Conductor. Nominal Area. Minimum Insulation Resistance, Megohms for a Mile Length at 60° F.
Rubber-insulated Cables. Paper-insulated Cables.
600-megohm Grade.* 2,500-megohm Grade.*†
1. 2. 3. 4. 5.
1/·036 Sq. in. Megohms. Megohms. Megohms.
1/·044 0·001 2,000 5,000 140
3/·029 0·0015 2,000 5,000 140
0·002 1,250 4,500 140
3/·036 0·003 1,250 4,500 140
1/·064 0·003 2,000 5,000 140
7/·029 0·0045 1,250 4,500 140
7/·036 0·007 900 4,000 140
7/·044 0·01 900 4,000 140
7/·052 0·0145 900 4,000 140
7/·064 0·0225 900 3,500 130
19/·044· 0·03 750 3,500 125
19/·052 0·04 750 3,000 115
19/·064 0·06 750 3,000 100
19/·072 0·075 600 3,000 85
19/·083 0·1 600 3,000 80
37/·064 0·12 600 3,000 75
37/·072 0·15 600 3,000 60
37/·083 0·2 600 2,500 55
37/·093 0·25 600 2,500 50
37/·103 0·3 600 2,500 50
61/·093 0·4 600 2,500 50
61/·103 0·5 600 2,500 45
91/·093 0·6 600 2,500 40
91/·103 0·75 600 2,500 40
127/·093 0·85 600 2,500 35
127/·103 1·0 600 2,500 35
  • For (a) Direct-current systems for pressures not varying from earth potential by more than 250 volts; (b) three-phase systems, with centre point earthed, for pressures not more than 500 volts between phases.

† For pressures not varying from earth potential by more than 650 volts.

TABLE X.—TEST PRESSURES FOR FLEXIBLE CORDS.

Kind. Insulating Material. Test Pressure and Frequency. Nature of Test.*
1. 2. 3. 4.
High insulation (a) Pure rubber } 1,500 volts Between conductors in
(b) Pure and/or vulcanized-rubber dry state.
(c) Homogeneous insulation } at 25–100
Medium insulation (a) Pure rubber 1,000 volts
(b) Homogeneous insulation 1,500 volts
  • Where a flexible cord has a covering purporting to be waterproof it shall be tested after twenty-four hours immersion in water.

TABLE XI.—INSULATION RESISTANCE OF FLEXIBLE CORDS HAVING VULCANIZED-RUBBER INSULATION.

Number and Diameter of Wires comprising Conductor. Nominal Area. Minimum Insulation Resistance, Megohms for a Mile Length at 60° F.
0·0076-in.-diameter Wires. 0·012-in.-diameter Wires. High Insulation. Medium Insulation.
1. 2. 3. 4. 5.
Sq. in. Megohms. Megohms.
14 — 0·0006 1,250 300
23 11 0·001 1,250 300
40 16 0·0017 1,250 300
70 28 0·003 1,250 300
110 44 0·0048 1,250 300
162 65 0·007 900 300


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✨ LLM interpretation of page content

🏗️ Insulation Resistance of Cables (continued from previous page)

🏗️ Infrastructure & Public Works
Insulation Resistance, Cables, Rubber-insulated, Paper-insulated, Electrical Standards

🏗️ Test Pressures for Flexible Cords

🏗️ Infrastructure & Public Works
Test Pressures, Flexible Cords, Insulating Material, Electrical Standards

🏗️ Insulation Resistance of Flexible Cords with Vulcanized-Rubber Insulation

🏗️ Infrastructure & Public Works
Insulation Resistance, Flexible Cords, Vulcanized-Rubber Insulation, Electrical Standards