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---
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title: "Circular of the Bureau of Standards No. 32: Copper Wire Tables"
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tags:
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- type/media/reference
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- exclude-from-word-count
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date: 1914-10-01
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---
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# Circular of the Bureau of Standards No. 32: Copper Wire Tables
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---
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title: "National Bureau of Standards Handbook 100: Copper Wire Tables"
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tags:
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- type/media/book
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- exclude-from-word-count
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date: 1966-02-21
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---
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# National Bureau of Standards Handbook 100: Copper Wire Tables
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---
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title: "NBS Handbook 109: Aluminum Wire Tables"
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tags:
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- type/media/reference
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- exclude-from-word-count
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date: 1972-02-00
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---
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# NBS Handbook 109: Aluminum Wire Tables
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+205
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---
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---
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aliases:
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aliases:
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- nec-ch9
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- nec-ch9
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- NEC Chapter 9 Tables
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title: Chapter 9 Tables
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title: Chapter 9 Tables
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tags:
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tags:
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- authorship/other
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- authorship/other
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@@ -83,12 +84,216 @@ tags:
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## Table 8 Conductor Properties
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## Table 8 Conductor Properties
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| | | | | | | | | | | | | | | | |
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| ------------------- | ----- | ------------- | ---------- | -------- | ----- | -------- | ----- | ----- | ----- | ----------------------------------------- | ------- | ------- | ------- | -------- | ------- |
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| Size (AWG or kcmil) | Area | < | Conductors | < | < | < | < | < | < | Direct-Current Resistance at 75°C (167°F) | < | < | < | < | < |
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| ^ | mm2 | Circular mils | Stranding | < | < | Overall | < | < | < | Copper | < | < | < | < | < |
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| ^ | ^ | ^ | Quantity | Diameter | < | Diameter | < | Area | < | Uncoated | < | Coated | < | Aluminum | < |
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| ^ | ^ | ^ | | mm | in. | mm | in. | mm2 | in | ohm/km | ohm/kFT | ohm/km | ohm/kFT | ohm/km | ohm/kFT |
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| 18 | 0.823 | 1620 | 1 | — | — | 1.02 | 0.04 | 0.823 | 0.001 | 25.5 | 7.77 | 26.5 | 8.08 | 42 | 12.8 |
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| 18 | 0.823 | 1620 | 7 | 0.39 | 0.015 | 1.16 | 0.046 | 1.06 | 0.002 | 26.1 | 7.95 | 27.7 | 8.45 | 42.8 | 13.1 |
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| 16 | 1.31 | 2580 | 1 | — | — | 1.29 | 0.051 | 1.31 | 0.002 | 16 | 4.89 | 16.7 | 5.08 | 26.4 | 8.05 |
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| 16 | 1.31 | 2580 | 7 | 0.49 | 0.019 | 1.46 | 0.058 | 1.68 | 0.003 | 16.4 | 4.99 | 17.3 | 5.29 | 26.9 | 8.21 |
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| 14 | 2.08 | 4110 | 1 | — | — | 1.63 | 0.064 | 2.08 | 0.003 | 10.1 | 3.07 | 10.4 | 3.19 | 16.6 | 5.06 |
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| 14 | 2.08 | 4110 | 7 | 0.62 | 0.024 | 1.85 | 0.073 | 2.68 | 0.004 | 10.3 | 3.14 | 10.7 | 3.26 | 16.9 | 5.17 |
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| 12 | 3.31 | 6530 | 1 | — | — | 2.05 | 0.081 | 3.31 | 0.005 | 6.34 | 1.93 | 6.57 | 2.01 | 10.45 | 3.18 |
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| 12 | 3.31 | 6530 | 7 | 0.78 | 0.03 | 2.32 | 0.092 | 4.25 | 0.006 | 6.5 | 1.98 | 6.73 | 2.05 | 10.69 | 3.25 |
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| 10 | 5.261 | 10380 | 1 | — | — | 2.588 | 0.102 | 5.26 | 0.008 | 3.984 | 1.21 | 4.148 | 1.26 | 6.561 | 2 |
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| 10 | 5.261 | 10380 | 7 | 0.98 | 0.038 | 2.95 | 0.116 | 6.76 | 0.011 | 4.07 | 1.24 | 4.226 | 1.29 | 6.679 | 2.04 |
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| 8 | 8.367 | 16510 | 1 | — | — | 3.264 | 0.128 | 8.37 | 0.013 | 2.506 | 0.764 | 2.579 | 0.786 | 4.125 | 1.26 |
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| 8 | 8.367 | 16510 | 7 | 1.23 | 0.049 | 3.71 | 0.146 | 10.76 | 0.017 | 2.551 | 0.778 | 2.653 | 0.809 | 4.204 | 1.28 |
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| 6 | 13.3 | 26240 | 7 | 1.56 | 0.061 | 4.67 | 0.184 | 17.09 | 0.027 | 1.608 | 0.491 | 1.671 | 0.51 | 2.652 | 0.808 |
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| 4 | 21.15 | 41740 | 7 | 1.96 | 0.077 | 5.89 | 0.232 | 27.19 | 0.042 | 1.01 | 0.308 | 1.053 | 0.321 | 1.666 | 0.508 |
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| 3 | 26.67 | 52620 | 7 | 2.2 | 0.087 | 6.6 | 0.26 | 34.28 | 0.053 | 0.802 | 0.245 | 0.833 | 0.254 | 1.32 | 0.403 |
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| 2 | 33.62 | 66360 | 7 | 2.47 | 0.097 | 7.42 | 0.292 | 43.23 | 0.067 | 0.634 | 0.194 | 0.661 | 0.201 | 1.045 | 0.319 |
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| 1 | 42.41 | 83690 | 19 | 1.69 | 0.066 | 8.43 | 0.332 | 55.8 | 0.087 | 0.505 | 0.154 | 0.524 | 0.16 | 0.829 | 0.253 |
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| 1/0 | 53.49 | 105600 | 19 | 1.89 | 0.074 | 9.45 | 0.372 | 70.41 | 0.109 | 0.399 | 0.122 | 0.415 | 0.127 | 0.66 | 0.201 |
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| 2/0 | 67.43 | 133100 | 19 | 2.13 | 0.084 | 10.62 | 0.418 | 88.74 | 0.137 | 0.317 | 0.0967 | 0.329 | 0.101 | 0.523 | 0.159 |
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| 3/0 | 85.01 | 167800 | 19 | 2.39 | 0.094 | 11.94 | 0.47 | 111.9 | 0.173 | 0.2512 | 0.0766 | 0.261 | 0.0797 | 0.413 | 0.126 |
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| 4/0 | 107.2 | 211600 | 19 | 2.68 | 0.106 | 13.41 | 0.528 | 141.1 | 0.219 | 0.1996 | 0.0608 | 0.205 | 0.0626 | 0.328 | 0.1 |
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| 250 | 127 | — | 37 | 2.09 | 0.082 | 14.61 | 0.575 | 168 | 0.26 | 0.1687 | 0.0515 | 0.1753 | 0.0535 | 0.2778 | 0.0847 |
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| 300 | 152 | — | 37 | 2.29 | 0.09 | 16 | 0.63 | 201 | 0.312 | 0.1409 | 0.0429 | 0.1463 | 0.0446 | 0.2318 | 0.0707 |
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| 350 | 177 | — | 37 | 2.47 | 0.097 | 17.3 | 0.681 | 235 | 0.364 | 0.1205 | 0.0367 | 0.1252 | 0.0382 | 0.1984 | 0.0605 |
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| 400 | 203 | — | 37 | 2.64 | 0.104 | 18.49 | 0.728 | 268 | 0.416 | 0.1053 | 0.0321 | 0.1084 | 0.0331 | 0.1737 | 0.0529 |
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| 500 | 253 | — | 37 | 2.95 | 0.116 | 20.65 | 0.813 | 336 | 0.519 | 0.0845 | 0.0258 | 0.0869 | 0.0265 | 0.1391 | 0.0424 |
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| 600 | 304 | — | 61 | 2.52 | 0.099 | 22.68 | 0.893 | 404 | 0.626 | 0.0704 | 0.0214 | 0.0732 | 0.0223 | 0.1159 | 0.0353 |
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| 700 | 355 | — | 61 | 2.72 | 0.107 | 24.49 | 0.964 | 471 | 0.73 | 0.0603 | 0.0184 | 0.0622 | 0.0189 | 0.0994 | 0.0303 |
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| 750 | 380 | — | 61 | 2.82 | 0.111 | 25.35 | 0.998 | 505 | 0.782 | 0.0563 | 0.0171 | 0.0579 | 0.0176 | 0.0927 | 0.0282 |
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| 800 | 405 | — | 61 | 2.91 | 0.114 | 26.16 | 1.03 | 538 | 0.834 | 0.0528 | 0.0161 | 0.0544 | 0.0166 | 0.0868 | 0.0265 |
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| 900 | 456 | — | 61 | 3.09 | 0.122 | 27.79 | 1.094 | 606 | 0.94 | 0.047 | 0.0143 | 0.0481 | 0.0147 | 0.077 | 0.0235 |
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| 1000 | 507 | — | 61 | 3.25 | 0.128 | 29.26 | 1.152 | 673 | 1.042 | 0.0423 | 0.0129 | 0.0434 | 0.0132 | 0.0695 | 0.0212 |
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| 1250 | 633 | — | 91 | 2.98 | 0.117 | 32.74 | 1.289 | 842 | 1.305 | 0.0338 | 0.0103 | 0.0347 | 0.0106 | 0.0554 | 0.0169 |
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| 1500 | 760 | — | 91 | 3.26 | 0.128 | 35.86 | 1.412 | 1011 | 1.566 | 0.02814 | 0.00858 | 0.02814 | 0.00883 | 0.0464 | 0.0141 |
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| 1750 | 887 | — | 127 | 2.98 | 0.117 | 38.76 | 1.526 | 1180 | 1.829 | 0.0241 | 0.00735 | 0.0241 | 0.00756 | 0.0397 | 0.0121 |
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| 2000 | 1013 | — | 127 | 3.19 | 0.126 | 41.45 | 1.632 | 1349 | 2.092 | 0.02109 | 0.00643 | 0.02109 | 0.00662 | 0.0348 | 0.0106 |
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Notes:
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1. These resistance values are valid only for the parameters as given.
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Using conductors having coated strands, different stranding type,
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and, especially, other temperatures changes the resistance.
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2. Equation for temperature change: $R_2 = R_1 [1 + \alpha (T_2—75)]$,
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where $\alpha_{cu}$ = 0.00323, $\alpha_{AL}$ = 0.00330 at 75°C.
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3. Conductors with compact and compressed stranding
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have about 9 percent and 3 percent, respectively,
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smaller bare conductor diameters than those shown.
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See Table 5A for actual compact cable dimensions.
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4. The IACS conductivities used: bare copper = 100%, aluminum = 61%.
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5. Class B stranding is listed as well as solid for some sizes.
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Its overall diameter and area are those of its circumscribing circle.
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> [!info] Informational Note:
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> The construction information is in accordance
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> with NEMA WC/70-2009 or ANSI/UL 1581-2017.
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>
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> The resistance is calculated in accordance
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> with National Bureau of Standards Handbook 100, dated 1966,
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> and Handbook 109, dated 1972.
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## Table 9 Alternating-Current Resistance and Reactance for 600-Volt Cables, 3-Phase, 60 Hz, 75°C (167°F) — Three Single Conductors in Conduit
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## Table 9 Alternating-Current Resistance and Reactance for 600-Volt Cables, 3-Phase, 60 Hz, 75°C (167°F) — Three Single Conductors in Conduit
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| ------------------- | ----------------------------- | ------------- | -------------------------------------------------------- | ---------------- | ------------- | ------------------------------------------------- | ---------------- | ------------- | ------------------------------------------------ | ---------------- | ------------- | ----------------------------------------- | ---------------- | ------------- | ------------------- |
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| Size (AWG or kcmil) | Ohms to Neutral per Kilometer | < | < | < | < | < | < | < | < | < | < | < | < | < | Size (AWG or kcmil) |
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| ^ | Ohms to Neutral per 1000 Feet | < | < | < | < | < | < | < | < | < | < | < | < | < | ^ |
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| ^ | XL (Reactance) for All Wires | < | Alternating-Current Resistance for Uncoated Copper Wires | < | < | Alternating-Current Resistance for Aluminum Wires | < | < | Effective Z at 0.85 PF for Uncoated Copper Wires | < | < | Effective Z at 0.85 PF for Aluminum Wires | < | < | ^ |
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| ^ | PVC, Aluminum Conduits | Steel Conduit | PVC Conduit | Aluminum Conduit | Steel Conduit | PVC Conduit | Aluminum Conduit | Steel Conduit | PVC Conduit | Aluminum Conduit | Steel Conduit | PVC Conduit | Aluminum Conduit | Steel Conduit | ^ |
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| 14 | 0.19 | 0.24 | 10.2 | 10.2 | 10.2 | — | — | — | 8.9 | 8.9 | 8.9 | — | — | — | 14 |
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| ^ | 0.058 | 0.073 | 3.1 | 3.1 | 3.1 | — | — | — | 2.7 | 2.7 | 2.7 | — | — | — | ^ |
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| 12 | 0.177 | 0.223 | 6.6 | 6.6 | 6.6 | 10.5 | 10.5 | 10.5 | 5.6 | 5.6 | 5.6 | 9.2 | 9.2 | 9.2 | 12 |
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| ^ | 0.054 | 0.068 | 2 | 2 | 2 | 3.2 | 3.2 | 3.2 | 1.7 | 1.7 | 1.7 | 2.8 | 2.8 | 2.8 | ^ |
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| 10 | 0.164 | 0.207 | 3.9 | 3.9 | 3.9 | 6.6 | 6.6 | 6.6 | 3.6 | 3.6 | 3.6 | 5.9 | 5.9 | 5.9 | 10 |
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| ^ | 0.05 | 0.063 | 1.2 | 1.2 | 1.2 | 2 | 2 | 2 | 1.1 | 1.1 | 1.1 | 1.8 | 1.8 | 1.8 | ^ |
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| 8 | 0.171 | 0.213 | 2.56 | 2.56 | 2.56 | 4.3 | 4.3 | 4.3 | 2.26 | 2.26 | 2.3 | 3.6 | 3.6 | 3.6 | 8 |
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| ^ | 0.052 | 0.065 | 0.78 | 0.78 | 0.78 | 1.3 | 1.3 | 1.3 | 0.69 | 0.69 | 0.7 | 1.1 | 1.1 | 1.1 | ^ |
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| 6 | 0.167 | 0.21 | 1.61 | 1.61 | 1.61 | 2.66 | 2.66 | 2.66 | 1.44 | 1.48 | 1.48 | 2.33 | 2.36 | 2.36 | 6 |
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| ^ | 0.051 | 0.064 | 0.49 | 0.49 | 0.49 | 0.81 | 0.81 | 0.81 | 0.44 | 0.45 | 0.45 | 0.71 | 0.72 | 0.72 | ^ |
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| 4 | 0.157 | 0.197 | 1.02 | 1.02 | 1.02 | 1.67 | 1.67 | 1.67 | 0.95 | 0.95 | 0.98 | 1.51 | 1.51 | 1.51 | 4 |
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| ^ | 0.048 | 0.06 | 0.31 | 0.31 | 0.31 | 0.51 | 0.51 | 0.51 | 0.29 | 0.29 | 0.3 | 0.46 | 0.46 | 0.46 | ^ |
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| 3 | 0.154 | 0.194 | 0.82 | 0.82 | 0.82 | 1.31 | 1.35 | 1.31 | 0.75 | 0.79 | 0.79 | 1.21 | 1.21 | 1.21 | 3 |
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| ^ | 0.047 | 0.059 | 0.25 | 0.25 | 0.25 | 0.4 | 0.41 | 0.4 | 0.23 | 0.24 | 0.24 | 0.37 | 0.37 | 0.37 | ^ |
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| 2 | 0.148 | 0.187 | 0.62 | 0.66 | 0.66 | 1.05 | 1.05 | 1.05 | 0.62 | 0.62 | 0.66 | 0.98 | 0.98 | 0.98 | 2 |
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| ^ | 0.045 | 0.057 | 0.19 | 0.2 | 0.2 | 0.32 | 0.32 | 0.32 | 0.19 | 0.19 | 0.2 | 0.3 | 0.3 | 0.3 | ^ |
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| 1 | 0.151 | 0.187 | 0.49 | 0.52 | 0.52 | 0.82 | 0.85 | 0.82 | 0.52 | 0.52 | 0.52 | 0.79 | 0.79 | 0.82 | 1 |
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| ^ | 0.046 | 0.057 | 0.15 | 0.16 | 0.16 | 0.25 | 0.26 | 0.25 | 0.16 | 0.16 | 0.16 | 0.24 | 0.24 | 0.25 | ^ |
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| 1/0 | 0.144 | 0.18 | 0.39 | 0.43 | 0.39 | 0.66 | 0.69 | 0.66 | 0.43 | 0.43 | 0.43 | 0.62 | 0.66 | 0.66 | 1/0 |
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| ^ | 0.044 | 0.055 | 0.12 | 0.13 | 0.12 | 0.2 | 0.21 | 0.2 | 0.13 | 0.13 | 0.13 | 0.19 | 0.2 | 0.2 | ^ |
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| 2/0 | 0.141 | 0.177 | 0.33 | 0.33 | 0.33 | 0.52 | 0.52 | 0.52 | 0.36 | 0.36 | 0.36 | 0.52 | 0.52 | 0.52 | 2/0 |
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| ^ | 0.043 | 0.054 | 0.1 | 0.1 | 0.1 | 0.16 | 0.16 | 0.16 | 0.11 | 0.11 | 0.11 | 0.16 | 0.16 | 0.16 | ^ |
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| 3/0 | 0.138 | 0.171 | 0.253 | 0.269 | 0.259 | 0.43 | 0.43 | 0.43 | 0.289 | 0.302 | 0.308 | 0.43 | 0.43 | 0.46 | 3/0 |
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| ^ | 0.042 | 0.052 | 0.077 | 0.082 | 0.079 | 0.13 | 0.13 | 0.13 | 0.088 | 0.092 | 0.094 | 0.13 | 0.13 | 0.14 | ^ |
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| 4/0 | 0.135 | 0.167 | 0.203 | 0.22 | 0.207 | 0.33 | 0.36 | 0.33 | 0.243 | 0.256 | 0.262 | 0.36 | 0.36 | 0.36 | 4/0 |
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| ^ | 0.041 | 0.051 | 0.062 | 0.067 | 0.063 | 0.1 | 0.11 | 0.1 | 0.074 | 0.078 | 0.08 | 0.11 | 0.11 | 0.11 | ^ |
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| 250 | 0.135 | 0.171 | 0.171 | 0.187 | 0.177 | 0.279 | 0.295 | 0.282 | 0.217 | 0.23 | 0.24 | 0.308 | 0.322 | 0.33 | 250 |
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| ^ | 0.041 | 0.052 | 0.052 | 0.057 | 0.054 | 0.085 | 0.09 | 0.086 | 0.066 | 0.07 | 0.073 | 0.094 | 0.098 | 0.1 | ^ |
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| 300 | 0.135 | 0.167 | 0.144 | 0.161 | 0.148 | 0.233 | 0.249 | 0.236 | 0.194 | 0.207 | 0.213 | 0.269 | 0.282 | 0.289 | 300 |
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| ^ | 0.041 | 0.051 | 0.044 | 0.049 | 0.045 | 0.071 | 0.076 | 0.072 | 0.059 | 0.063 | 0.065 | 0.082 | 0.086 | 0.088 | ^ |
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| 350 | 0.131 | 0.164 | 0.125 | 0.141 | 0.128 | 0.2 | 0.217 | 0.207 | 0.174 | 0.19 | 0.197 | 0.24 | 0.253 | 0.262 | 350 |
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| ^ | 0.04 | 0.05 | 0.038 | 0.043 | 0.039 | 0.061 | 0.066 | 0.063 | 0.053 | 0.058 | 0.06 | 0.073 | 0.077 | 0.08 | ^ |
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| 400 | 0.131 | 0.161 | 0.108 | 0.125 | 0.115 | 0.177 | 0.194 | 0.18 | 0.161 | 0.174 | 0.184 | 0.217 | 0.233 | 0.24 | 400 |
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| ^ | 0.04 | 0.049 | 0.033 | 0.038 | 0.035 | 0.054 | 0.059 | 0.055 | 0.049 | 0.053 | 0.056 | 0.066 | 0.071 | 0.073 | ^ |
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||||||
|
| 500 | 0.128 | 0.157 | 0.089 | 0.105 | 0.095 | 0.141 | 0.157 | 0.148 | 0.141 | 0.157 | 0.164 | 0.187 | 0.2 | 0.21 | 500 |
|
||||||
|
| ^ | 0.039 | 0.048 | 0.027 | 0.032 | 0.029 | 0.043 | 0.048 | 0.045 | 0.043 | 0.048 | 0.05 | 0.057 | 0.061 | 0.064 | ^ |
|
||||||
|
| 600 | 0.128 | 0.157 | 0.075 | 0.092 | 0.082 | 0.118 | 0.135 | 0.125 | 0.131 | 0.144 | 0.154 | 0.167 | 0.18 | 0.19 | 600 |
|
||||||
|
| ^ | 0.039 | 0.048 | 0.023 | 0.028 | 0.025 | 0.036 | 0.041 | 0.038 | 0.04 | 0.044 | 0.047 | 0.051 | 0.055 | 0.058 | ^ |
|
||||||
|
| 750 | 0.125 | 0.157 | 0.062 | 0.079 | 0.069 | 0.095 | 0.112 | 0.102 | 0.118 | 0.131 | 0.141 | 0.148 | 0.161 | 0.171 | 750 |
|
||||||
|
| ^ | 0.038 | 0.048 | 0.019 | 0.024 | 0.021 | 0.029 | 0.034 | 0.031 | 0.036 | 0.04 | 0.043 | 0.045 | 0.049 | 0.052 | ^ |
|
||||||
|
| 1000 | 0.121 | 0.151 | 0.049 | 0.062 | 0.059 | 0.075 | 0.089 | 0.082 | 0.105 | 0.118 | 0.131 | 0.128 | 0.138 | 0.151 | 1000 |
|
||||||
|
| ^ | 0.037 | 0.046 | 0.015 | 0.019 | 0.018 | 0.023 | 0.027 | 0.025 | 0.032 | 0.036 | 0.04 | 0.039 | 0.042 | 0.046 | ^ |
|
||||||
|
|
||||||
|
Notes:
|
||||||
|
|
||||||
|
1. These values are based on the following constants:
|
||||||
|
UL-Type RHH wires with Class B stranding, in cradled configuration.
|
||||||
|
Wire conductivities are 100 percent IACS copper
|
||||||
|
and 61 percent IACS aluminum,
|
||||||
|
and aluminum conduit is 45 percent IACS.
|
||||||
|
Capacitive reactance is ignored, since it is negligible at these voltages.
|
||||||
|
These resistance values are valid only at 75°C (167°F)
|
||||||
|
and for the parameters as given,
|
||||||
|
but are representative for 600-volt wire types operating at 60 Hz.
|
||||||
|
|
||||||
|
2. _Effective Z_ is defined as $R \cos(\theta) + X sin(\theta)$,
|
||||||
|
where $\theta$ is the power factor angle of the circuit.
|
||||||
|
Multiplying current by effective impedance
|
||||||
|
gives a good approximation for line-to-neutral voltage drop.
|
||||||
|
Effective impedance values shown in this table
|
||||||
|
are valid only at 0.85 power factor.
|
||||||
|
For another circuit power factor (PF),
|
||||||
|
effective impedance ($Z_{e}$) can be calculated
|
||||||
|
from $R$ and $X_{L}$ values given in this table as follows:
|
||||||
|
$Z_{e} = R \times \rm{PF} + X_{L} \sin[\arccos(\rm{PF})]$.
|
||||||
|
|
||||||
## Table 10 Conductor Stranding
|
## Table 10 Conductor Stranding
|
||||||
|
|
||||||
|
| | | | | |
|
||||||
|
| -------------- | --------- | ------------------- | ------- | ------------------- |
|
||||||
|
| Conductor Size | < | Number of Strands | < | < |
|
||||||
|
| -------------- | --------- | ----------------- | ------- | -------- |
|
||||||
|
| AWG or kcmil | mm2 | Copper | < | Aluminum |
|
||||||
|
| ^ | ^ | Class B<sup>a</sup> | Class C | Class B<sup>a</sup> |
|
||||||
|
| 24—30 | 0.20—0.05 | b | — | — |
|
||||||
|
| 22 | 0.32 | 7 | — | — |
|
||||||
|
| 20 | 0.52 | 10 | — | — |
|
||||||
|
| 18 | 0.82 | 16 | — | — |
|
||||||
|
| 16 | 1.3 | 26 | — | — |
|
||||||
|
| 14—2 | 2.1—33.6 | 7 | 19 | 7c |
|
||||||
|
| 1—4/0 | 42.4—107 | 19 | 37 | 19 |
|
||||||
|
| 250—500 | 127—253 | 37 | 61 | 37 |
|
||||||
|
| 600—1000 | 304—508 | 61 | 91 | 61 |
|
||||||
|
| 1250—1500 | 635—759 | 91 | 127 | 91 |
|
||||||
|
| 1750—2000 | 886—1016 | 127 | 271 | 127 |
|
||||||
|
|
||||||
|
<sup>a</sup>Conductors with a lesser number of strands shall be permitted
|
||||||
|
based on an evaluation for connectability and bending.
|
||||||
|
|
||||||
|
<sup>b</sup>Number of strands vary.
|
||||||
|
|
||||||
|
<sup>c</sup>Aluminum 14 AWG (2.1 mm<sup>2</sup>) is not available.
|
||||||
|
|
||||||
|
With the permission of Underwriters Laboratories, Inc.,
|
||||||
|
material is reproduced from UL Standard 486A-486B, *Wire Connectors*,
|
||||||
|
which is copyrighted by Underwriters Laboratories, Inc., Northbrook, Illinois.
|
||||||
|
While use of this material has been authorized,
|
||||||
|
UL shall not be responsible for the manner in which the information is presented,
|
||||||
|
nor for any interpretations thereof.
|
||||||
|
For more information on UL or to purchase standards,
|
||||||
|
please visit our Standards website at www.comm-2000.com
|
||||||
|
or call 1-888-853-3503.
|
||||||
|
|
||||||
## Table 11(A) and Table 11(B)
|
## Table 11(A) and Table 11(B)
|
||||||
|
|
||||||
|
For listing purposes,
|
||||||
|
Table 11(A) and Table 11(B) provide the required power source limitations
|
||||||
|
for Class 2 and Class 3 power sources.
|
||||||
|
Table 11 (A) applies for alternating-current sources,
|
||||||
|
and Table 11(B) applies for direct-current sources.
|
||||||
|
|
||||||
|
The power for Class 2 and Class 3 circuits
|
||||||
|
shall be either (1) inherently limited, requiring no overcurrent protection,
|
||||||
|
or (2) not inherently limited,
|
||||||
|
requiring a combination of power source and overcurrent protection.
|
||||||
|
Power sources designed for interconnection
|
||||||
|
shall be listed for the purpose.
|
||||||
|
|
||||||
|
As part of the listing, the Class 2 or Class 3 power source
|
||||||
|
shall be durably marked where plainly visible
|
||||||
|
to indicate the class of supply and its electrical rating.
|
||||||
|
A Class 2 power source not suitable for wet location use shall be so marked.
|
||||||
|
|
||||||
|
> Exception:
|
||||||
|
> Limited power circuits used by listed information technology equipment.
|
||||||
|
|
||||||
|
Overcurrent devices, where required,
|
||||||
|
shall be located at the point
|
||||||
|
where the conductor to be protected receives its supply
|
||||||
|
and shall not be interchangeable with devices of higher ratings.
|
||||||
|
The overcurrent device shall be permitted as an integral part of the power source.
|
||||||
|
|
||||||
### Table 11(A) Class 2 and Class 3 Alternating-Current Power Source Limitations
|
### Table 11(A) Class 2 and Class 3 Alternating-Current Power Source Limitations
|
||||||
|
|
||||||
### Table 11(B) Class 2 and Class 3 Direct-Current Power Source Limitations
|
### Table 11(B) Class 2 and Class 3 Direct-Current Power Source Limitations
|
||||||
|
|||||||
@@ -22,7 +22,7 @@ is how little the workflow would change if it was.
|
|||||||
[^1]: Programs like this are called CRUD (Create Read Update Delete) apps.
|
[^1]: Programs like this are called CRUD (Create Read Update Delete) apps.
|
||||||
|
|
||||||
If you were to replace the Takeoff tab with a command prompt,
|
If you were to replace the Takeoff tab with a command prompt,
|
||||||
this is what it would look like to take off (2) receptacles:
|
this is what it would look like to take off two receptacles:
|
||||||
|
|
||||||
```sql
|
```sql
|
||||||
INSERT INTO Takeoff (drawing,area,phase,system,bid_item,labor_factor,assembly,length,count)
|
INSERT INTO Takeoff (drawing,area,phase,system,bid_item,labor_factor,assembly,length,count)
|
||||||
|
|||||||
@@ -0,0 +1,60 @@
|
|||||||
|
---
|
||||||
|
id: 2026-05-19T09:48:52-0400
|
||||||
|
title: 2026-05-19 09:48:52
|
||||||
|
tags: []
|
||||||
|
daily: "[[2026-05-19]]"
|
||||||
|
---
|
||||||
|
# 2026-05-19 09:48:52
|
||||||
|
|
||||||
|
## Wire Properties
|
||||||
|
|
||||||
|
### Resistance
|
||||||
|
|
||||||
|
NEC Chapter 9 Tables [[nfpa-70_ch09#Table 8 Conductor Properties|8]]
|
||||||
|
and [[nfpa-70_ch09#Table 9 Alternating-Current Resistance and Reactance for 600-Volt Cables, 3-Phase, 60 Hz, 75°C (167°F) — Three Single Conductors in Conduit|9]]
|
||||||
|
provide resistance values for sizes and materials of wires,
|
||||||
|
stated in their notes to be based on calculations
|
||||||
|
found in [[nbs_1966_handbook-100]]
|
||||||
|
and [[nbs_1972_handbook-109]].
|
||||||
|
|
||||||
|
#### International Annealed Copper Standard
|
||||||
|
|
||||||
|
The same tables give conductor conductivity as a percent of
|
||||||
|
[International Annealed Copper Standard (IACS)](https://en.wikipedia.org/wiki/International_Annealed_Copper_Standard),
|
||||||
|
viz. 100% for copper and 61% for aluminum.
|
||||||
|
|
||||||
|
The definition of the IACS,
|
||||||
|
as originally published in [[nbs_1914_circular-031]] is
|
||||||
|
|
||||||
|
$$
|
||||||
|
100\%\ \rm{IACS} \equiv 0.15328~\text{ohm (meter, gram) at 20°C},
|
||||||
|
$$
|
||||||
|
|
||||||
|
alternately denoted in [[nbs_1966_handbook-100]] as
|
||||||
|
|
||||||
|
$$
|
||||||
|
0.15328~\text{ohm-gram/meter$^2$ at 20°C}.
|
||||||
|
$$
|
||||||
|
|
||||||
|
These definitions are for **mass resistivity**.
|
||||||
|
|
||||||
|
**Volume resistivity** can be derived
|
||||||
|
using the density of copper at the same temperature,
|
||||||
|
|
||||||
|
$$
|
||||||
|
8.89~\text{gram/cm$^3$ at 20°C},
|
||||||
|
$$
|
||||||
|
|
||||||
|
or
|
||||||
|
|
||||||
|
$$
|
||||||
|
0.32117~\text{lb/in.$^3$ at 20°C}.
|
||||||
|
$$
|
||||||
|
|
||||||
|
The derived value of volume resistivity given by [[nbs_1966_handbook-100]] is
|
||||||
|
|
||||||
|
$$
|
||||||
|
0.017241~\text{ohm-mm$^2$/meter at 20°C}.
|
||||||
|
$$
|
||||||
|
|
||||||
|
equal to 58 S/mm at 20°C.
|
||||||
@@ -0,0 +1,105 @@
|
|||||||
|
---
|
||||||
|
id: 2026-05-19T12:23:11-0400
|
||||||
|
title: 2026-05-19 12:23:11
|
||||||
|
tags: []
|
||||||
|
daily: "[[2026-05-19]]"
|
||||||
|
---
|
||||||
|
# 2026-05-19 12:23:11
|
||||||
|
|
||||||
|
## Resistivity and Conductivity
|
||||||
|
|
||||||
|
In [[2026-04-14_15-50-06]] I described the relationship
|
||||||
|
between the resistance and conductance...
|
||||||
|
|
||||||
|
[**Resistance** and **conductance**](https://en.wikipedia.org/wiki/Electrical_resistance_and_conductance)
|
||||||
|
are properties of electrical "objects" or "elements".
|
||||||
|
[**Resistivity** and **conductivity**](https://en.wikipedia.org/wiki/Electrical_resistivity_and_conductivity) are properties of **materials**.[^1]
|
||||||
|
|
||||||
|
[^1]: It would be more accurate to describe this relationship
|
||||||
|
in terms of [intensive and extensive properties](https://en.wikipedia.org/wiki/Intensive_and_extensive_properties).
|
||||||
|
The resistance and conductance of a copper bar
|
||||||
|
would not change if the cube doubled in size,
|
||||||
|
but its resistivity and conductivity
|
||||||
|
|
||||||
|
> Resistivity is commonly represented by the Greek letter ρ (rho).
|
||||||
|
> The SI unit of electrical resistivity is the ohm-meter (Ω⋅m).
|
||||||
|
|
||||||
|
> Electrical conductivity (or specific conductance)
|
||||||
|
> is the reciprocal of electrical resistivity.
|
||||||
|
> It represents a material's ability to conduct electric current.
|
||||||
|
> It is commonly signified by the Greek letter σ (sigma),
|
||||||
|
> but κ (kappa) (especially in electrical engineering) and γ (gamma)
|
||||||
|
> are sometimes used.
|
||||||
|
> The SI unit of electrical conductivity is siemens per meter (S/m).
|
||||||
|
|
||||||
|
The meaning of these units are not intuitive,
|
||||||
|
but are better understood from the ideal case
|
||||||
|
diagrammed below:
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
The **resistance** of the conductor
|
||||||
|
is directly proportional to its length $\ell$,
|
||||||
|
and inversely proportional to its cross-sectional area $A$.
|
||||||
|
|
||||||
|
$$
|
||||||
|
R \propto {\frac{\ell}{A}}
|
||||||
|
$$
|
||||||
|
|
||||||
|
Let electrical resistivity $\rho$ be the constant of proportionality.
|
||||||
|
|
||||||
|
$$
|
||||||
|
R = \rho \frac{\ell}{A}
|
||||||
|
$$
|
||||||
|
|
||||||
|
(This equation is known as **Pouillet's law**,
|
||||||
|
after [Claude Pouillet](https://en.wikipedia.org/wiki/Claude_Pouillet))
|
||||||
|
|
||||||
|
$$
|
||||||
|
\Leftrightarrow \rho = R \frac{A}{\ell},
|
||||||
|
$$
|
||||||
|
|
||||||
|
where
|
||||||
|
|
||||||
|
* $R$ is the electrical resistance of a uniform specimen of the material
|
||||||
|
* $\ell$ is the length of the specimen
|
||||||
|
* $A$ is the cross-sectional area of the specimen
|
||||||
|
|
||||||
|
The meaning of the ohm-meter (Ω⋅m) in this context is difficult to grok.
|
||||||
|
Wikipedia describes it thus:
|
||||||
|
|
||||||
|
> ...ohms multiplied by square meters (for the cross-sectional area)
|
||||||
|
> then divided by meters (for the length).
|
||||||
|
|
||||||
|
%%
|
||||||
|
|
||||||
|
The **conductance** of the conductor
|
||||||
|
is _inversely_ proportional to its length $\ell$,
|
||||||
|
and _directly_ proportional to its cross-sectional area $A$.
|
||||||
|
|
||||||
|
$$
|
||||||
|
G \propto {\frac{A}{\ell}}
|
||||||
|
$$
|
||||||
|
|
||||||
|
Let electrical conductivity $\sigma$ be the constant of proportionality.
|
||||||
|
|
||||||
|
$$
|
||||||
|
\begin{aligned}
|
||||||
|
R &= \sigma \frac{A}{\ell} \\
|
||||||
|
\Leftrightarrow \sigma &= G \frac{\ell}{A},
|
||||||
|
\end{aligned}
|
||||||
|
$$
|
||||||
|
|
||||||
|
where
|
||||||
|
|
||||||
|
* $G$ is the electrical resistance of a uniform specimen of the material
|
||||||
|
* $\ell$ is the length of the specimen
|
||||||
|
* $A$ is the cross-sectional area of the specimen
|
||||||
|
|
||||||
|
%%
|
||||||
|
|
||||||
|
Conductivity, $\sigma$, is the inverse of resistivity:
|
||||||
|
|
||||||
|
$$
|
||||||
|
\sigma = \frac{1}{\rho}
|
||||||
|
$$
|
||||||
+15
-5
@@ -6,9 +6,19 @@ up: "[[writing]]"
|
|||||||
---
|
---
|
||||||
# Uncommon Syntax
|
# Uncommon Syntax
|
||||||
|
|
||||||
* **i.e.** --- _id est_ ("that is")
|
* [**i.e.**](https://en.wikipedia.org/wiki/List_of_Latin_phrases_(I)#id_est)
|
||||||
|
--- _id est_ ("that is")
|
||||||
|
|
||||||
* **e.g.** --- _exempli gratia_ ("for example")
|
* [**e.g.**](https://en.wikipedia.org/wiki/Exempli_gratia)
|
||||||
|
--- _exempli gratia_ ("for example")
|
||||||
|
|
||||||
|
* [**viz.**](https://en.wikipedia.org/wiki/Viz.)
|
||||||
|
--- _videlicet_, from _videre licet_ ("which is")
|
||||||
|
|
||||||
|
> In contrast to i.e. and e.g.,
|
||||||
|
> viz. is used to indicate a detailed description of something stated before,
|
||||||
|
> and when it precedes a list of group members,
|
||||||
|
> it implies (near) completeness.
|
||||||
|
|
||||||
## Symbols
|
## Symbols
|
||||||
|
|
||||||
@@ -32,10 +42,10 @@ up: "[[writing]]"
|
|||||||
> [!cite] [Compound point - Wikipedia](https://en.wikipedia.org/wiki/Compound_point)
|
> [!cite] [Compound point - Wikipedia](https://en.wikipedia.org/wiki/Compound_point)
|
||||||
> * **;---** --- Semicolon dash.
|
> * **;---** --- Semicolon dash.
|
||||||
> A more emphatic or longer semicolon.
|
> A more emphatic or longer semicolon.
|
||||||
>
|
>
|
||||||
> * **.---** --- Stop dash.
|
> * **.---** --- Stop dash.
|
||||||
> A full stop that emphasizes the sentence it starts.
|
> A full stop that emphasizes the sentence it starts.
|
||||||
>
|
>
|
||||||
> * **,---** --- Comma dash.
|
> * **,---** --- Comma dash.
|
||||||
> A mark used in various ways:
|
> A mark used in various ways:
|
||||||
> to mark parentheticals
|
> to mark parentheticals
|
||||||
@@ -45,7 +55,7 @@ up: "[[writing]]"
|
|||||||
> as a more emphatic comma;
|
> as a more emphatic comma;
|
||||||
> or for separating several clauses with a common dependence
|
> or for separating several clauses with a common dependence
|
||||||
> from the clause on which they depend.
|
> from the clause on which they depend.
|
||||||
>
|
>
|
||||||
> * **:---** --- Colon dash.
|
> * **:---** --- Colon dash.
|
||||||
> A mark that indicates a list, the contents of which start on the next line; or as a more emphatic colon.
|
> A mark that indicates a list, the contents of which start on the next line; or as a more emphatic colon.
|
||||||
|
|
||||||
|
|||||||
Reference in New Issue
Block a user