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"", "vimVisualMode": "", "vimMatrixEnter": "o" diff --git a/Untitled.md b/Untitled.md new file mode 100644 index 0000000..e69de29 diff --git a/nbs_1914_circular-031.md b/nbs_1914_circular-031.md new file mode 100644 index 0000000..9588a62 --- /dev/null +++ b/nbs_1914_circular-031.md @@ -0,0 +1,8 @@ +--- +title: "Circular of the Bureau of Standards No. 32: Copper Wire Tables" +tags: + - type/media/reference + - exclude-from-word-count +date: 1914-10-01 +--- +# Circular of the Bureau of Standards No. 32: Copper Wire Tables diff --git a/nbs_1966_handbook-100.md b/nbs_1966_handbook-100.md new file mode 100644 index 0000000..e0971c1 --- /dev/null +++ b/nbs_1966_handbook-100.md @@ -0,0 +1,8 @@ +--- +title: "National Bureau of Standards Handbook 100: Copper Wire Tables" +tags: + - type/media/book + - exclude-from-word-count +date: 1966-02-21 +--- +# National Bureau of Standards Handbook 100: Copper Wire Tables diff --git a/nbs_1972_handbook-109.md b/nbs_1972_handbook-109.md new file mode 100644 index 0000000..d7c405a --- /dev/null +++ b/nbs_1972_handbook-109.md @@ -0,0 +1,8 @@ +--- +title: "NBS Handbook 109: Aluminum Wire Tables" +tags: + - type/media/reference + - exclude-from-word-count +date: 1972-02-00 +--- +# NBS Handbook 109: Aluminum Wire Tables diff --git a/nfpa-70_ch09.md b/nfpa-70_ch09.md index cce3c35..bd91a0e 100644 --- a/nfpa-70_ch09.md +++ b/nfpa-70_ch09.md @@ -1,6 +1,7 @@ --- aliases: - nec-ch9 + - NEC Chapter 9 Tables title: Chapter 9 Tables tags: - authorship/other @@ -83,12 +84,216 @@ tags: ## Table 8 Conductor Properties +| | | | | | | | | | | | | | | | | +| ------------------- | ----- | ------------- | ---------- | -------- | ----- | -------- | ----- | ----- | ----- | ----------------------------------------- | ------- | ------- | ------- | -------- | ------- | +| Size (AWG or kcmil) | Area | < | Conductors | < | < | < | < | < | < | Direct-Current Resistance at 75°C (167°F) | < | < | < | < | < | +| ^ | mm2 | Circular mils | Stranding | < | < | Overall | < | < | < | Copper | < | < | < | < | < | +| ^ | ^ | ^ | Quantity | Diameter | < | Diameter | < | Area | < | Uncoated | < | Coated | < | Aluminum | < | +| ^ | ^ | ^ | | mm | in. | mm | in. | mm2 | in | ohm/km | ohm/kFT | ohm/km | ohm/kFT | ohm/km | ohm/kFT | +| 18 | 0.823 | 1620 | 1 | — | — | 1.02 | 0.04 | 0.823 | 0.001 | 25.5 | 7.77 | 26.5 | 8.08 | 42 | 12.8 | +| 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 | +| 16 | 1.31 | 2580 | 1 | — | — | 1.29 | 0.051 | 1.31 | 0.002 | 16 | 4.89 | 16.7 | 5.08 | 26.4 | 8.05 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 10 | 5.261 | 10380 | 1 | — | — | 2.588 | 0.102 | 5.26 | 0.008 | 3.984 | 1.21 | 4.148 | 1.26 | 6.561 | 2 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | +| 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 | + +Notes: + +1. These resistance values are valid only for the parameters as given. + Using conductors having coated strands, different stranding type, + and, especially, other temperatures changes the resistance. + +2. Equation for temperature change: $R_2 = R_1 [1 + \alpha (T_2—75)]$, + where $\alpha_{cu}$ = 0.00323, $\alpha_{AL}$ = 0.00330 at 75°C. + +3. Conductors with compact and compressed stranding + have about 9 percent and 3 percent, respectively, + smaller bare conductor diameters than those shown. + See Table 5A for actual compact cable dimensions. + +4. The IACS conductivities used: bare copper = 100%, aluminum = 61%. + +5. Class B stranding is listed as well as solid for some sizes. + Its overall diameter and area are those of its circumscribing circle. + +> [!info] Informational Note: +> The construction information is in accordance +> with NEMA WC/70-2009 or ANSI/UL 1581-2017. +> +> The resistance is calculated in accordance +> with National Bureau of Standards Handbook 100, dated 1966, +> and Handbook 109, dated 1972. + ## Table 9 Alternating-Current Resistance and Reactance for 600-Volt Cables, 3-Phase, 60 Hz, 75°C (167°F) — Three Single Conductors in Conduit +| | | | | | | | | | | | | | | | | +| ------------------- | ----------------------------- | ------------- | -------------------------------------------------------- | ---------------- | ------------- | ------------------------------------------------- | ---------------- | ------------- | ------------------------------------------------ | ---------------- | ------------- | ----------------------------------------- | ---------------- | ------------- | ------------------- | +| Size (AWG or kcmil) | Ohms to Neutral per Kilometer | < | < | < | < | < | < | < | < | < | < | < | < | < | Size (AWG or kcmil) | +| ^ | Ohms to Neutral per 1000 Feet | < | < | < | < | < | < | < | < | < | < | < | < | < | ^ | +| ^ | 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 | < | < | ^ | +| ^ | 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 | ^ | +| 14 | 0.19 | 0.24 | 10.2 | 10.2 | 10.2 | — | — | — | 8.9 | 8.9 | 8.9 | — | — | — | 14 | +| ^ | 0.058 | 0.073 | 3.1 | 3.1 | 3.1 | — | — | — | 2.7 | 2.7 | 2.7 | — | — | — | ^ | +| 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 | +| ^ | 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 | ^ | +| 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 | +| ^ | 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 | ^ | +| 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 | +| ^ | 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 | ^ | +| 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 | +| ^ | 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 | ^ | +| 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 | +| ^ | 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 | ^ | +| 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 | +| ^ | 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 | ^ | +| 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 | +| ^ | 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 | ^ | +| 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 | +| ^ | 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 | ^ | +| 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 | +| ^ | 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 | ^ | +| 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 | +| ^ | 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 | ^ | +| 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 | +| ^ | 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 | ^ | +| 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 | +| ^ | 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 | ^ | +| 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 | +| ^ | 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 | ^ | +| 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 | +| ^ | 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 | ^ | +| 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 | +| ^ | 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 | ^ | +| 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 | +| ^ | 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 | ^ | +| 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 +| | | | | | +| -------------- | --------- | ------------------- | ------- | ------------------- | +| Conductor Size | < | Number of Strands | < | < | +| -------------- | --------- | ----------------- | ------- | -------- | +| AWG or kcmil | mm2 | Copper | < | Aluminum | +| ^ | ^ | Class Ba | Class C | Class Ba | +| 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 | + +aConductors with a lesser number of strands shall be permitted +based on an evaluation for connectability and bending. + +bNumber of strands vary. + +cAluminum 14 AWG (2.1 mm2) 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) +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(B) Class 2 and Class 3 Direct-Current Power Source Limitations diff --git a/timestamped/2026-02-28_12-02-03.md b/timestamped/2026-02-28_12-02-03.md index 9b7312d..eb109c1 100644 --- a/timestamped/2026-02-28_12-02-03.md +++ b/timestamped/2026-02-28_12-02-03.md @@ -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. 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 INSERT INTO Takeoff (drawing,area,phase,system,bid_item,labor_factor,assembly,length,count) diff --git a/timestamped/2026-05-19_09-48-52.md b/timestamped/2026-05-19_09-48-52.md new file mode 100644 index 0000000..2fad5c5 --- /dev/null +++ b/timestamped/2026-05-19_09-48-52.md @@ -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. diff --git a/timestamped/2026-05-19_12-23-11.md b/timestamped/2026-05-19_12-23-11.md new file mode 100644 index 0000000..771f1bc --- /dev/null +++ b/timestamped/2026-05-19_12-23-11.md @@ -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: + +![](https://upload.wikimedia.org/wikipedia/commons/6/68/Resistivity_geometry.png) + +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: + +$$ +\sigma = \frac{1}{\rho} +$$ \ No newline at end of file diff --git a/uncommon-syntax.md b/uncommon-syntax.md index 720fe97..63ad31b 100644 --- a/uncommon-syntax.md +++ b/uncommon-syntax.md @@ -6,9 +6,19 @@ up: "[[writing]]" --- # 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 @@ -32,10 +42,10 @@ up: "[[writing]]" > [!cite] [Compound point - Wikipedia](https://en.wikipedia.org/wiki/Compound_point) > * **;---** --- Semicolon dash. > A more emphatic or longer semicolon. -> +> > * **.---** --- Stop dash. > A full stop that emphasizes the sentence it starts. -> +> > * **,---** --- Comma dash. > A mark used in various ways: > to mark parentheticals @@ -45,7 +55,7 @@ up: "[[writing]]" > as a more emphatic comma; > or for separating several clauses with a common dependence > from the clause on which they depend. -> +> > * **:---** --- Colon dash. > A mark that indicates a list, the contents of which start on the next line; or as a more emphatic colon.