voltage-drop-calculations

<p>The voltage drop of any insulated cable is dependent upon the route length under consideration (in meters), the required current rating (in amperes) and the relevant total impedance per unit length of the cable. The maximum impedance and voltage drop applicable to each cable at maximum conductor temperature and under a.c. conditions is given in the tables. For cables operating under dc conditions, the appropriate voltage drops may be calculated using the formula.</p>
<blockquote>
<p><strong>2 x route length x current x resistance x 10¯³</strong>.</p>
</blockquote>
<p>The values detailed in the tables are given in m/V/Am, (volts/100 per ampere per metre), and the nominal<br />maximum acceptable volt drop specified by the IEE Regulations is 2.5% of the system voltage, i.e. 0.025 x 415<br />= 10.5 volts for 3 phase working or 0.025 x 240 = 6.0 volts for single phase working.</p>
<p><strong>Consider a 3 phase system</strong><br />The requirement may be for a load of 1000A to be transmitted over a route length of 150m, the cable to be<br />clipped to the wall and close protection provided. The rating tables in the IEE Regulations indicate that a<br />35mm copper conductor PVC SWA PVC cable would be suitable for the loading required, but the voltage drop<br />must be checked.</p>
<p>Volt drop = Y x current x length<br />= 1.1 x 100 x 150 millivolts<br />= 1.1 x 100 x 150 volts/1000<br />= 16.5 volts<br />where Y = value from tables in mV/A/m Unless a particular value of voltage drop, acceptable to the user, is<br />specified, the IEE Regulations figure of 10.5 volts must be adhered to.</p>
<p>Thus: total volt drop = 10.5 volts<br />10.5 = Y x 100 x 150<br />Therefore Y = 10.5/100 x 150<br />= 0.7/1000 volts/ampere/meters</p>
<p>Reference to the voltage drop tables indicates that the cable size with a voltage drop of 0.7/1000 V/A/m<br />(0.7mV/A/m) OR LESS is a 70mm copper conductor.</p>
<p>Therefore, in order to transmit a 3 phase current of 100A per phase over a route length of 150m, with a total<br />voltage drop equal to or less than the statutory maximum 10.5 volts, the use would require a<br />70mm (cu.) multicore PVC.</p>
<p><strong>Conversely</strong><br />The user may have 150m of 35mm (Cu.) multicore PVC cable and require to know what maximum current<br />rating can be applied without exceeding the allowable voltage drop. The method is exactly the same as above,<br />viz:total drop = 16.6</p>
<p>= YxAxM<br />= 1.1 x A x 150/1000<br />from the tables Y = 1.1mV/A/m<br />=1.1/1000V/A/m<br />therefore A = 10.5 x 1000/1.1.x 150<br />=64 amperes</p>
<p>From the foregoing, it is apparent that knowing any two values of Y, A or m, the remaining, unknown value can<br />readily be calculated.</p>
<p>The advice is always available to check, clarify or suggest the most suitable size and type of cable for any particular, specified requirements.</p>
<h2>Voltage Drop for Single Core LV Cables (mV / amp / metre)</h2>
<table border="0" width="100%" cellspacing="2" cellpadding="2">
<tbody>
<tr class="tablesheadback">
<td align="center"><strong>Copper Conductor</strong></td>
<td align="center">&gt;<strong>Flat Arrangement</strong></td>
<td align="center"><strong>Trefoil arrangement</strong></td>
<td align="center"><strong>Aluminium conductor</strong></td>
<td align="center"><strong>Flat arrangement</strong></td>
<td align="center"><strong>Trefoil arrangement</strong></td>
</tr>
<tr>
<td align="center">4</td>
<td align="center">7.83</td>
<td align="center">7.770</td>
<td align="center">16</td>
<td align="center">3.343</td>
<td align="center">3.283</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">6</td>
<td align="center">5.287</td>
<td align="center">5.226</td>
<td align="center">25</td>
<td align="center">2.161</td>
<td align="center">2.100</td>
</tr>
<tr>
<td align="center">10</td>
<td align="center">3.184</td>
<td align="center">3.124</td>
<td align="center">35</td>
<td align="center">1.602</td>
<td align="center">1.542</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">16</td>
<td align="center">2.086</td>
<td align="center">2.008</td>
<td align="center">50</td>
<td align="center">1.222</td>
<td align="center">1.162</td>
</tr>
<tr>
<td align="center">25</td>
<td align="center">1.357</td>
<td align="center">1.297</td>
<td align="center">70</td>
<td align="center">0.890</td>
<td align="center">0.830</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">35</td>
<td align="center">1.034</td>
<td align="center">0.971</td>
<td align="center">95</td>
<td align="center">0.686</td>
<td align="center">0.623</td>
</tr>
<tr>
<td align="center">50</td>
<td align="center">0.793</td>
<td align="center">0.732</td>
<td align="center">120</td>
<td align="center">0.569</td>
<td align="center">0.509</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">70</td>
<td align="center">0.595</td>
<td align="center">0.534</td>
<td align="center">150</td>
<td align="center">0.490</td>
<td align="center">0.430</td>
</tr>
<tr>
<td align="center">95</td>
<td align="center">0.469</td>
<td align="center">0.408</td>
<td align="center">185</td>
<td align="center">0.420</td>
<td align="center">0.360</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">120</td>
<td align="center">0.410</td>
<td align="center">0.349</td>
<td align="center">240</td>
<td align="center">0.353</td>
<td align="center">0.293</td>
</tr>
<tr>
<td align="center">150</td>
<td align="center">0.354</td>
<td align="center">0.294</td>
<td align="center">300</td>
<td align="center">0.312</td>
<td align="center">0.252</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">185</td>
<td align="center">0.312</td>
<td align="center">0.252</td>
<td align="center">400</td>
<td align="center">0.274</td>
<td align="center">0.214</td>
</tr>
<tr>
<td align="center">240</td>
<td align="center">0.272</td>
<td align="center">0.211</td>
<td align="center">400</td>
<td align="center">0.245</td>
<td align="center">0.185</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">300</td>
<td align="center">0.247</td>
<td align="center">0.187</td>
<td align="center">630</td>
<td align="center">0.222</td>
<td align="center">0.162</td>
</tr>
<tr>
<td align="center">400</td>
<td align="center">0.224</td>
<td align="center">0.164</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
</tr>
<tr bgcolor="#b19aca">
<td align="center" bgcolor="#b19aca">500</td>
<td align="center">0.208</td>
<td align="center">0.148</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
</tr>
<tr>
<td align="center">630</td>
<td align="center">0.194</td>
<td align="center">0.134</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
</tr>
</tbody>
</table>
<p> </p>
<h2>VOLTAGE DROP PER AMPERE PER METER (mV). Conductor operating temperature: 70ºC</h2>
<table width="100%" cellspacing="2" cellpadding="2">
<tbody>
<tr class="tablesheadback">
<td align="center">Conductor Cross Sectional Area</td>
<td align="center">Two Core Cable D.C.</td>
<td colspan="3" align="center">Two Core Cable SIngle Phase A.C.</td>
<td colspan="3" align="center">Three or Four Core Cable Three phase A.C.</td>
</tr>
<tr class="tablesheadback">
<td align="center">mm</td>
<td align="center">mV</td>
<td colspan="3" align="center">mV</td>
<td colspan="3" align="center">mV</td>
</tr>
<tr>
<td align="center">1.5</td>
<td align="center">29</td>
<td colspan="3" align="center">29</td>
<td colspan="3" align="center">25</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">2.5</td>
<td align="center">18</td>
<td colspan="3" align="center">18</td>
<td colspan="3" align="center">15</td>
</tr>
<tr>
<td align="center">4</td>
<td align="center">11</td>
<td colspan="3" align="center">11</td>
<td colspan="3" align="center">9.05</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">6</td>
<td align="center">7.3</td>
<td colspan="3" align="center">7.3</td>
<td colspan="3" align="center">6.04</td>
</tr>
<tr>
<td align="center">10</td>
<td align="center">4.4</td>
<td colspan="3" align="center">4.4</td>
<td colspan="3" align="center">3.08</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">16</td>
<td align="center">2.8</td>
<td colspan="3" align="center">2.8</td>
<td colspan="3" align="center">2.04</td>
</tr>
<tr>
<td align="center"> </td>
<td align="center"> </td>
<td class="tablesheadback" align="center">r</td>
<td class="tablesheadback" align="center">x</td>
<td class="tablesheadback" align="center">z</td>
<td class="tablesheadback" align="center">r</td>
<td class="tablesheadback" align="center">x</td>
<td class="tablesheadback" align="center">z</td>
</tr>
<tr>
<td align="center">25</td>
<td align="center">1.75</td>
<td align="center">1.75</td>
<td align="center">0.170</td>
<td align="center">1.75</td>
<td align="center">1.50</td>
<td align="center">0.145</td>
<td align="center">1.50</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">35</td>
<td align="center">1.25</td>
<td align="center">1.25</td>
<td align="center">0.165</td>
<td align="center">1.25</td>
<td align="center">1.10</td>
<td align="center">0.145</td>
<td align="center">1.10</td>
</tr>
<tr>
<td align="center">50</td>
<td align="center">0.93</td>
<td align="center">0.93</td>
<td align="center">0.165</td>
<td align="center">0.94</td>
<td align="center">0.80</td>
<td align="center">0.140</td>
<td align="center">0.81</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">70</td>
<td align="center">0.63</td>
<td align="center">0.63</td>
<td align="center">0.160</td>
<td align="center">0.65</td>
<td align="center">0.55</td>
<td align="center">0.140</td>
<td align="center">0.57</td>
</tr>
<tr>
<td align="center">95</td>
<td align="center">0.46</td>
<td align="center">0.47</td>
<td align="center">0.155</td>
<td align="center">0.50</td>
<td align="center">0.41</td>
<td align="center">0.135</td>
<td align="center">0.43</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">120</td>
<td align="center">0.36</td>
<td align="center">0.38</td>
<td align="center">0.155</td>
<td align="center">0.41</td>
<td align="center">0.33</td>
<td align="center">0.135</td>
<td align="center">0.35</td>
</tr>
<tr>
<td align="center">150</td>
<td align="center">0.29</td>
<td align="center">0.30</td>
<td align="center">0.155</td>
<td align="center">0.34</td>
<td align="center">0.26</td>
<td align="center">0.130</td>
<td align="center">0.29</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">185</td>
<td align="center">0.23</td>
<td align="center">0.28</td>
<td align="center">0.150</td>
<td align="center">0.29</td>
<td align="center">0.21</td>
<td align="center">0.130</td>
<td align="center">0.25</td>
</tr>
<tr>
<td align="center">240</td>
<td align="center">0.180</td>
<td align="center">0.190</td>
<td align="center">0.150</td>
<td align="center">0.24</td>
<td align="center">0.165</td>
<td align="center">0.130</td>
<td align="center">0.21</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">300</td>
<td align="center">0.145</td>
<td align="center">0.155</td>
<td align="center">0.145</td>
<td align="center">0.21</td>
<td align="center">0.136</td>
<td align="center">0.130</td>
<td align="center">0.185</td>
</tr>
<tr>
<td align="center">400</td>
<td align="center">0.105</td>
<td align="center">0.115</td>
<td align="center">0.145</td>
<td align="center">0.185</td>
<td align="center">0.100</td>
<td align="center">0.125</td>
<td align="center">0.160</td>
</tr>
</tbody>
</table>
<p> </p>
<h2>VOLTAGE DROP PER AMPERE PER METRE (mV).  Conductor operating temperature: 70ºc</h2>
<table width="100%" cellspacing="2">
<tbody>
<tr class="tablesheadback">
<td align="center"><strong>Conductor Cross-Sectional Area</strong></td>
<td align="center"><strong>Two Core Cable D.C.</strong></td>
<td colspan="3" align="center"><strong>TWo Core Cable Single Phase A.C.</strong></td>
<td colspan="3" align="center"><strong>Three or Four Core Cable Three Phase A.C.</strong></td>
</tr>
<tr class="tablesheadback">
<td align="center">1</td>
<td align="center">2</td>
<td colspan="3" align="center">3</td>
<td colspan="3" align="center">4</td>
</tr>
<tr class="tablesheadback">
<td align="center">Mm</td>
<td align="center">Mv</td>
<td colspan="3" align="center">MV</td>
<td colspan="3" align="center">MV</td>
</tr>
<tr>
<td align="center">16</td>
<td align="center">4.5</td>
<td colspan="3" align="center">45</td>
<td colspan="3" align="center">3.9</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">25</td>
<td align="center">2.9</td>
<td align="center">29</td>
<td align="center">0.175</td>
<td align="center">2.9</td>
<td align="center">2.5</td>
<td align="center">0.150</td>
<td align="center">2.5</td>
</tr>
<tr>
<td align="center">35</td>
<td align="center">2.1</td>
<td align="center">2.1</td>
<td align="center">0.170</td>
<td align="center">2.1</td>
<td align="center">1.80</td>
<td align="center">0.150</td>
<td align="center">1.80</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">50</td>
<td align="center">1.55</td>
<td align="center">1.55</td>
<td align="center">0.170</td>
<td align="center">1.55</td>
<td align="center">1.35</td>
<td align="center">0.145</td>
<td align="center">1.35</td>
</tr>
<tr>
<td align="center">70</td>
<td align="center">1.05</td>
<td align="center">1.05</td>
<td align="center">0.165</td>
<td align="center">1.05</td>
<td align="center">0.90</td>
<td align="center">0.140</td>
<td align="center">0.92</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">95</td>
<td align="center">0.77</td>
<td align="center">0.77</td>
<td align="center">0.160</td>
<td align="center">0.79</td>
<td align="center">0.67</td>
<td align="center">0.140</td>
<td align="center">0.68</td>
</tr>
<tr>
<td align="center">120</td>
<td align="center">-</td>
<td align="center">-</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center">0.53</td>
<td align="center">0.135</td>
<td align="center">0.55</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">150</td>
<td align="center">-</td>
<td align="center">-</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center">0.42</td>
<td align="center">0.135</td>
<td align="center">0.44</td>
</tr>
<tr>
<td align="center">185</td>
<td align="center">-</td>
<td align="center">-</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center">0.34</td>
<td align="center">0.135</td>
<td align="center">0.37</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">240</td>
<td align="center">-</td>
<td align="center">-</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center">0.26</td>
<td align="center">0.130</td>
<td align="center">0.30</td>
</tr>
<tr>
<td align="center">300</td>
<td align="center">-</td>
<td align="center">-</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center">0.21</td>
<td align="center">0.130</td>
<td align="center">0.25</td>
</tr>
</tbody>
</table>
<p>Tables derive from IEE copyright information</p>
<h2>PVC INSULATED 600/1000 VOLT CABLES WITH COPPER CONDUCTORS SUSTAINED CURRENT RATING (AMP) (50Hz) PARAMETERS</h2>
<table width="100%" cellspacing="2" cellpadding="2">
<tbody>
<tr class="tablesheadback">
<td align="center"><strong>Normal Conductor Area</strong></td>
<td colspan="4" align="center"><strong>600/100 VOLT<br />THREE-PHASE SINGLE CORE CABLES IN TREFOIL ARRANGEMENT</strong></td>
</tr>
<tr class="tablesheadback">
<td align="center"><strong>mm</strong></td>
<td align="center"><strong>Direct Armoured</strong></td>
<td align="center"><strong>Duct Armoured</strong></td>
<td align="center"><strong>Air Unarmoured</strong></td>
<td align="center"><strong>Air Armoured</strong></td>
</tr>
<tr>
<td align="center">50</td>
<td align="center">203</td>
<td align="center">199</td>
<td align="center">184</td>
<td align="center">193</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">70</td>
<td align="center">248</td>
<td align="center">241</td>
<td align="center">233</td>
<td align="center">249</td>
</tr>
<tr>
<td align="center">95</td>
<td align="center">297</td>
<td align="center">282</td>
<td align="center">290</td>
<td align="center">298</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">120</td>
<td align="center">337</td>
<td align="center">311</td>
<td align="center">338</td>
<td align="center">347</td>
</tr>
<tr>
<td align="center">150</td>
<td align="center">376</td>
<td align="center">342</td>
<td align="center">338</td>
<td align="center">395</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">185</td>
<td align="center">423</td>
<td align="center">375</td>
<td align="center">450</td>
<td align="center">452</td>
</tr>
<tr>
<td align="center">240</td>
<td align="center">485</td>
<td align="center">419</td>
<td align="center">537</td>
<td align="center">532</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">300</td>
<td align="center">542</td>
<td align="center">459</td>
<td align="center">620</td>
<td align="center">607</td>
</tr>
<tr>
<td align="center">700</td>
<td align="center">600</td>
<td align="center">489</td>
<td align="center">722</td>
<td align="center">690</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">500</td>
<td align="center">660</td>
<td align="center">523</td>
<td align="center">832</td>
<td align="center">776</td>
</tr>
<tr>
<td align="center">630</td>
<td align="center">721</td>
<td align="center">563</td>
<td align="center">957</td>
<td align="center">869</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">800</td>
<td align="center">758</td>
<td align="center">587</td>
<td align="center">1083</td>
<td align="center">937</td>
</tr>
<tr>
<td align="center">1000</td>
<td align="center">797</td>
<td align="center">621</td>
<td align="center">1260</td>
<td align="center">1010</td>
</tr>
</tbody>
</table>
<p> </p>
<h2>APPROXIMATE CURRENT PER LINE OR PHASE TAKEN AT FULL RATED HP BY MOTORS OF AVERAGE EFFICIENCY AND POWER FACTOR</h2>
<table width="100%" cellspacing="2" cellpadding="2">
<tbody>
<tr class="tablesheadback">
<td align="center"><strong>Motor Rating</strong></td>
<td colspan="3" align="center"><strong>Direct Current</strong></td>
<td colspan="4" align="center"><strong>Alternating Current</strong></td>
</tr>
<tr class="tablesheadback">
<td align="center"> </td>
<td align="center"><strong>110V</strong></td>
<td align="center"><strong>220V</strong></td>
<td align="center"><strong>550V</strong></td>
<td align="center"><strong>240V</strong></td>
<td align="center"><strong>380V</strong></td>
<td align="center"><strong>415V</strong></td>
<td align="center"><strong>550V</strong></td>
</tr>
<tr class="tablesheadback">
<td align="center"><strong>HP</strong></td>
<td align="center"><strong>amp</strong></td>
<td align="center"><strong>amp</strong></td>
<td align="center"><strong>amp</strong></td>
<td align="center"><strong>amp</strong></td>
<td align="center"><strong>amp</strong></td>
<td align="center"><strong>amp</strong></td>
<td align="center"><strong>amp</strong></td>
</tr>
<tr>
<td align="center">0.5</td>
<td align="center">5.7</td>
<td align="center">2.8</td>
<td align="center">1.1</td>
<td align="center">3</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">1</td>
<td align="center">10</td>
<td align="center">5</td>
<td align="center">2</td>
<td align="center">6</td>
<td align="center">1.9</td>
<td align="center">1.7</td>
<td align="center">1.3</td>
</tr>
<tr>
<td align="center">2</td>
<td align="center">18</td>
<td align="center">9</td>
<td align="center">3.6</td>
<td align="center">10</td>
<td align="center">3.6</td>
<td align="center">3.3</td>
<td align="center">2.5</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">3</td>
<td align="center">26</td>
<td align="center">13</td>
<td align="center">5.2</td>
<td align="center">15</td>
<td align="center">5.1</td>
<td align="center">4.6</td>
<td align="center">3.5</td>
</tr>
<tr>
<td align="center">5</td>
<td align="center">42</td>
<td align="center">21</td>
<td align="center">8.4</td>
<td align="center">24</td>
<td align="center">8</td>
<td align="center">7.3</td>
<td align="center">5.5</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">7.5</td>
<td align="center">60</td>
<td align="center">30</td>
<td align="center">12</td>
<td align="center">35</td>
<td align="center">11.6</td>
<td align="center">10.6</td>
<td align="center">8</td>
</tr>
<tr>
<td align="center">10</td>
<td align="center">80</td>
<td align="center">40</td>
<td align="center">16</td>
<td align="center">46</td>
<td align="center">15.1</td>
<td align="center">13.8</td>
<td align="center">10.4</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">15</td>
<td align="center">117</td>
<td align="center">59</td>
<td align="center">23</td>
<td align="center">67</td>
<td align="center">22</td>
<td align="center">20</td>
<td align="center">16</td>
</tr>
<tr>
<td align="center">20</td>
<td align="center">154</td>
<td align="center">77</td>
<td align="center">31</td>
<td align="center">88</td>
<td align="center">29</td>
<td align="center">27</td>
<td align="center">21</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">25</td>
<td align="center">190</td>
<td align="center">95</td>
<td align="center">38</td>
<td align="center">110</td>
<td align="center">37</td>
<td align="center">34</td>
<td align="center">26</td>
</tr>
<tr>
<td align="center">30</td>
<td align="center">227</td>
<td align="center">114</td>
<td align="center">46</td>
<td align="center">130</td>
<td align="center">43</td>
<td align="center">40</td>
<td align="center">30</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">40</td>
<td align="center">300</td>
<td align="center">150</td>
<td align="center">60</td>
<td align="center">180</td>
<td align="center">59</td>
<td align="center">54</td>
<td align="center">41</td>
</tr>
<tr>
<td align="center">50</td>
<td align="center">375</td>
<td align="center">187</td>
<td align="center">75</td>
<td align="center">210</td>
<td align="center">73</td>
<td align="center">67</td>
<td align="center">50</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">50</td>
<td align="center">445</td>
<td align="center">223</td>
<td align="center">89</td>
<td align="center">253</td>
<td align="center">87</td>
<td align="center">80</td>
<td align="center">60</td>
</tr>
<tr>
<td align="center">60</td>
<td align="center">520</td>
<td align="center">260</td>
<td align="center">104</td>
<td align="center">291</td>
<td align="center">102</td>
<td align="center">94</td>
<td align="center">70</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">80</td>
<td align="center">600</td>
<td align="center">300</td>
<td align="center">120</td>
<td align="center">332</td>
<td align="center">117</td>
<td align="center">107</td>
<td align="center">81</td>
</tr>
<tr>
<td align="center">100</td>
<td align="center">740</td>
<td align="center">370</td>
<td align="center">148</td>
<td align="center">412</td>
<td align="center">145</td>
<td align="center">133</td>
<td align="center">100</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">125</td>
<td align="center"> </td>
<td align="center">460</td>
<td align="center">184</td>
<td align="center">515</td>
<td align="center">181</td>
<td align="center">166</td>
<td align="center">125</td>
</tr>
<tr>
<td align="center">150</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center">220</td>
<td align="center"> </td>
<td align="center">217</td>
<td align="center">199</td>
<td align="center">150</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">175</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center">256</td>
<td align="center"> </td>
<td align="center">253</td>
<td align="center">232</td>
<td align="center">175</td>
</tr>
<tr>
<td align="center">200</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center">292</td>
<td align="center"> </td>
<td align="center">288</td>
<td align="center">264</td>
<td align="center">199</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">250</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center">353</td>
<td align="center">323</td>
<td align="center">244</td>
</tr>
<tr>
<td align="center">300</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center">421</td>
<td align="center">385</td>
<td align="center">291</td>
</tr>
</tbody>
</table>
<h2>Useful three phase formulae:</h2>
<p>1. kW = kVA x power factor</p>
<table id="table13" border="0" width="250" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td rowspan="2">2. kW =</td>
<td width="199">
<p align="center">Line amps x Line volts x 1.73 x p.f.</p>
</td>
</tr>
<tr>
<td width="199">
<p align="center">1000</p>
</td>
</tr>
</tbody>
</table>
<p> </p>
<table id="table14" border="0" width="250" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td rowspan="2" width="75">3. kVA =</td>
<td align="center">kW</td>
</tr>
<tr>
<td align="center">p.f.</td>
</tr>
</tbody>
</table>
<p> </p>
<table id="table15" border="0" width="250" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td rowspan="2" width="76">4. Line amps =</td>
<td align="center">kW x 1000</td>
</tr>
<tr>
<td align="center">Line volts x 1.73 x p.f.</td>
</tr>
</tbody>
</table>
<p> </p>
<table id="table16" border="0" width="250" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td rowspan="2" width="76">5. Line amps =</td>
<td align="center">kVA x 1000</td>
</tr>
<tr>
<td align="center">Line volts x 1.73</td>
</tr>
</tbody>
</table>
<p> </p>
<table id="table17" border="0" width="250" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td rowspan="2" width="76">6. Line amps =</td>
<td align="center">h.p. x 746</td>
</tr>
<tr>
<td align="center">Line volts x 1.73 x Efficiency x p.f.</td>
</tr>
</tbody>
</table>
<p> </p>
<table id="table18" border="0" width="250" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td rowspan="2" width="76">7. kVA =</td>
<td align="center">Line amps x Line volts x 1.73</td>
</tr>
<tr>
<td align="center">1000</td>
</tr>
</tbody>
</table>
<p> </p>
<table id="table19" border="0" width="250" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td rowspan="2" width="76">8. kW =</td>
<td align="center">h.p. x 746</td>
</tr>
<tr>
<td align="center">1000 x Efficiency</td>
</tr>
</tbody>
</table>
<p> </p>
<table id="table20" border="0" width="308" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td rowspan="2" width="76">9. kVA =</td>
<td align="center">Line amps x Line volts x 1.73 x Efficiency x p.f.</td>
</tr>
<tr>
<td align="center">746</td>
</tr>
</tbody>
</table>
<p> </p>
<table id="table21" border="0" width="250" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td rowspan="2" width="76">10. h.p. =</td>
<td align="center"> kW x 1000 x Efficiency</td>
</tr>
<tr>
<td align="center">746</td>
</tr>
</tbody>
</table>
<p> </p>
<table id="table22" border="0" width="250" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td rowspan="2" width="76">11. h.p. =</td>
<td align="center">kVA x 1000 x Efficiency</td>
</tr>
<tr>
<td align="center">746</td>
</tr>
</tbody>
</table>
<p> </p>
<h2>CURRENT RATINGS OF CABLES CLIPPED DIRECT TO SURFACE OR TRAY BUNCHED AND UNENCLOSED</h2>
<table width="100%" cellspacing="2" cellpadding="2">
<tbody>
<tr>
<td class="tablesheadback" rowspan="3" align="center"><strong>Conductor Size</strong></td>
<td class="tablesheadback" colspan="2" align="center"><strong>2 ONe-Core D.C.</strong></td>
<td class="tablesheadback" colspan="2" align="center"><strong>3 One-Core<br />4 One-Core</strong></td>
<td class="tablesheadback" colspan="2" align="center"><strong>1 Two Core DV</strong></td>
<td class="tablesheadback" colspan="2" align="center"><strong>1 Three Core<br />1 Four Core</strong></td>
</tr>
<tr class="tablesheadback">
<td colspan="2" align="center"><strong>One Phase A.C.</strong></td>
<td colspan="2" align="center"><strong>Three Phase A.C.</strong></td>
<td colspan="2" align="center"><strong>One-Phase A.C.</strong></td>
<td colspan="2" align="center"><strong>Three Phase A.C.</strong></td>
</tr>
<tr class="tablesheadback">
<td align="center"><strong>R</strong></td>
<td align="center"><strong>P</strong></td>
<td align="center"><strong>R</strong></td>
<td align="center"><strong>P</strong></td>
<td align="center"><strong>R</strong></td>
<td align="center"><strong>P</strong></td>
<td align="center"><strong>R</strong></td>
<td align="center"><strong>P</strong></td>
</tr>
<tr class="tablesheadback">
<td align="center">mm²</td>
<td align="center">amp</td>
<td align="center">amp</td>
<td align="center">amp</td>
<td align="center">amp</td>
<td align="center">amp</td>
<td align="center">amp</td>
<td align="center">amp</td>
<td align="center">amp</td>
</tr>
<tr>
<td align="center">1</td>
<td align="center">16</td>
<td align="center">13</td>
<td align="center">15</td>
<td align="center">12</td>
<td align="center">14</td>
<td align="center">12</td>
<td align="center">12</td>
<td align="center">10</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">1.5</td>
<td align="center">21</td>
<td align="center">16</td>
<td align="center">19</td>
<td align="center">15</td>
<td align="center">18</td>
<td align="center">15</td>
<td align="center">15</td>
<td align="center">13</td>
</tr>
<tr>
<td align="center">2.5</td>
<td align="center">29</td>
<td align="center">23</td>
<td align="center">26</td>
<td align="center">20</td>
<td align="center">24</td>
<td align="center">21</td>
<td align="center">21</td>
<td align="center">18</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">4</td>
<td align="center">38</td>
<td align="center">30</td>
<td align="center">34</td>
<td align="center">27</td>
<td align="center">31</td>
<td align="center">27</td>
<td align="center">27</td>
<td align="center">24</td>
</tr>
<tr>
<td align="center">6</td>
<td align="center">49</td>
<td align="center">38</td>
<td align="center">45</td>
<td align="center">34</td>
<td align="center">40</td>
<td align="center">35</td>
<td align="center">35</td>
<td align="center">30</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">10</td>
<td align="center">67</td>
<td align="center">51</td>
<td align="center">60</td>
<td align="center">46</td>
<td align="center">56</td>
<td align="center">48</td>
<td align="center">48</td>
<td align="center">41</td>
</tr>
<tr>
<td align="center">16</td>
<td align="center">90</td>
<td align="center">38</td>
<td align="center">81</td>
<td align="center">61</td>
<td align="center">72</td>
<td align="center">64</td>
<td align="center">64</td>
<td align="center">54</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">25</td>
<td align="center">115</td>
<td align="center">89</td>
<td align="center">105</td>
<td align="center">80</td>
<td align="center">96</td>
<td align="center">71</td>
<td align="center">84</td>
<td align="center">62</td>
</tr>
<tr>
<td align="center">35</td>
<td align="center">145</td>
<td align="center">109</td>
<td align="center">130</td>
<td align="center">98</td>
<td align="center">115</td>
<td align="center">87</td>
<td align="center">100</td>
<td align="center">72</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">50</td>
<td align="center">205</td>
<td align="center">175</td>
<td align="center">185</td>
<td align="center">160</td>
<td align="center">170</td>
<td align="center">140</td>
<td align="center">150</td>
<td align="center">125</td>
</tr>
<tr>
<td align="center">70</td>
<td align="center">260</td>
<td align="center">220</td>
<td align="center">235</td>
<td align="center">200</td>
<td align="center">210</td>
<td align="center">175</td>
<td align="center">185</td>
<td align="center">155</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">95</td>
<td align="center">320</td>
<td align="center">270</td>
<td align="center">285</td>
<td align="center">240</td>
<td align="center">255</td>
<td align="center">215</td>
<td align="center">225</td>
<td align="center">190</td>
</tr>
<tr>
<td align="center">120</td>
<td align="center">370</td>
<td align="center">310</td>
<td align="center">335</td>
<td align="center">280</td>
<td align="center">300</td>
<td align="center">250</td>
<td align="center">260</td>
<td align="center">215</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">150</td>
<td align="center">420</td>
<td align="center">355</td>
<td align="center">380</td>
<td align="center">320</td>
<td align="center">335</td>
<td align="center">285</td>
<td align="center">300</td>
<td align="center">250</td>
</tr>
<tr>
<td align="center">185</td>
<td align="center">480</td>
<td align="center">405</td>
<td align="center">435</td>
<td align="center">365</td>
<td align="center">385</td>
<td align="center">325</td>
<td align="center">345</td>
<td align="center">280</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">240</td>
<td align="center">570</td>
<td align="center">480</td>
<td align="center">520</td>
<td align="center">430</td>
<td align="center">450</td>
<td align="center">385</td>
<td align="center">400</td>
<td align="center">335</td>
</tr>
<tr>
<td align="center">300</td>
<td align="center">660</td>
<td align="center">560</td>
<td align="center">600</td>
<td align="center">500</td>
<td align="center">520</td>
<td align="center">445</td>
<td align="center">460</td>
<td align="center">390</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">400</td>
<td align="center">770</td>
<td align="center">680</td>
<td align="center">700</td>
<td align="center">610</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
</tr>
<tr>
<td align="center">500</td>
<td align="center">890</td>
<td align="center">800</td>
<td align="center">800</td>
<td align="center">710</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">630</td>
<td align="center">1050</td>
<td align="center">910</td>
<td align="center">950</td>
<td align="center">820</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
</tr>
</tbody>
</table>
<p> </p>
<h2>CURRENT RATINGS OF CABLES IN CONDUIT OR TRUNKING BUNCHED AND ENCLOSED</h2>
<table width="100%" cellspacing="2" cellpadding="2">
<tbody>
<tr>
<td class="tablesheadback" rowspan="2" align="center"><strong>Conductor Size</strong></td>
<td class="tablesheadback" colspan="2" align="center"><strong>2 One Core D.C.</strong></td>
<td class="tablesheadback" colspan="2" align="center"><strong>4 One Core</strong></td>
<td class="tablesheadback" colspan="2" align="center"><strong>D.C.</strong></td>
<td class="tablesheadback" colspan="2" align="center"><strong>Three Phase A.C.</strong></td>
</tr>
<tr class="tablesheadback">
<td colspan="2" align="center"><strong>One Phase AC</strong></td>
<td colspan="2" align="center"><strong>Three Phase AC</strong></td>
<td colspan="2" align="center"><strong>One Phase AC</strong></td>
<td align="center"> </td>
<td align="center"> </td>
</tr>
<tr>
<td class="tablesheadback" align="center"> </td>
<td class="tablesheadback" align="center">R</td>
<td class="tablesheadback" align="center">P</td>
<td class="tablesheadback" align="center">R</td>
<td class="tablesheadback" align="center">P</td>
<td class="tablesheadback" align="center">R</td>
<td class="tablesheadback" align="center">P</td>
<td class="tablesheadback" align="center">R</td>
<td class="tablesheadback" align="center">P</td>
</tr>
<tr>
<td class="tablesheadback" align="center">mm²</td>
<td class="tablesheadback" align="center">amp</td>
<td class="tablesheadback" align="center">amp</td>
<td class="tablesheadback" align="center">amp</td>
<td class="tablesheadback" align="center">amp</td>
<td class="tablesheadback" align="center">amp</td>
<td class="tablesheadback" align="center">amp</td>
<td class="tablesheadback" align="center">amp</td>
<td class="tablesheadback" align="center">amp</td>
</tr>
<tr>
<td align="center">1</td>
<td align="center">14</td>
<td align="center">11</td>
<td align="center">11</td>
<td align="center">9</td>
<td align="center">12</td>
<td align="center">11</td>
<td align="center">10</td>
<td align="center">9</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">1.5</td>
<td align="center">17</td>
<td align="center">13</td>
<td align="center">14</td>
<td align="center">11</td>
<td align="center">15</td>
<td align="center">13</td>
<td align="center">13</td>
<td align="center">12</td>
</tr>
<tr>
<td align="center">2.5</td>
<td align="center">24</td>
<td align="center">18</td>
<td align="center">20</td>
<td align="center">16</td>
<td align="center">20</td>
<td align="center">18</td>
<td align="center">17</td>
<td align="center">16</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">4</td>
<td align="center">31</td>
<td align="center">24</td>
<td align="center">27</td>
<td align="center">22</td>
<td align="center">27</td>
<td align="center">24</td>
<td align="center">23</td>
<td align="center">22</td>
</tr>
<tr>
<td align="center">6</td>
<td align="center">40</td>
<td align="center">31</td>
<td align="center">35</td>
<td align="center">28</td>
<td align="center">34</td>
<td align="center">30</td>
<td align="center">30</td>
<td align="center">27</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">10</td>
<td align="center">55</td>
<td align="center">42</td>
<td align="center">49</td>
<td align="center">39</td>
<td align="center">47</td>
<td align="center">40</td>
<td align="center">41</td>
<td align="center">37</td>
</tr>
<tr>
<td align="center">16</td>
<td align="center">73</td>
<td align="center">56</td>
<td align="center">66</td>
<td align="center">53</td>
<td align="center">61</td>
<td align="center">53</td>
<td align="center">54</td>
<td align="center">47</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">25</td>
<td align="center">94</td>
<td align="center">73</td>
<td align="center">89</td>
<td align="center">71</td>
<td align="center">80</td>
<td align="center">60</td>
<td align="center">70</td>
<td align="center">53</td>
</tr>
<tr>
<td align="center">35</td>
<td align="center">115</td>
<td align="center">90</td>
<td align="center">110</td>
<td align="center">88</td>
<td align="center">97</td>
<td align="center">74</td>
<td align="center">86</td>
<td align="center">65</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">50</td>
<td align="center">170</td>
<td align="center">145</td>
<td align="center">145</td>
<td align="center">125</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
</tr>
<tr>
<td align="center">70</td>
<td align="center">215</td>
<td align="center">185</td>
<td align="center">185</td>
<td align="center">160</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">95</td>
<td align="center">265</td>
<td align="center">230</td>
<td align="center">225</td>
<td align="center">195</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
</tr>
<tr>
<td align="center">120</td>
<td align="center">310</td>
<td align="center">260</td>
<td align="center">260</td>
<td align="center">220</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
</tr>
<tr bgcolor="#b19aca">
<td align="center">150</td>
<td align="center">350</td>
<td align="center"> </td>
<td align="center">300</td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
<td align="center"> </td>
</tr>
</tbody>
</table>
<p>R = Heat-resisting rubber insulation<br />P = PVC insulation</p>
<h2>MINIMUM SIZE OF EARTH CONDUCTOR (IF NOT CONTAINED IN CABLE)</h2>
<table width="100%" cellspacing="2" cellpadding="2">
<tbody>
<tr class="tablesheadback">
<td align="center" width="150">Size of largest associated copper circuit conductor</td>
<td align="center" width="150">Size of Earthing Conductor</td>
<td align="center" width="150">Size of Earthing Continuity Conductor</td>
<td align="center" width="150">Size of Bonding Lead</td>
</tr>
<tr>
<td align="center" width="150">1</td>
<td align="center" width="150">6</td>
<td align="center" width="150">1*</td>
<td align="center" width="150">1#*</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center" width="150">1.5</td>
<td align="center" width="150">6</td>
<td align="center" width="150">1*</td>
<td align="center" width="150">1#*</td>
</tr>
<tr>
<td align="center" width="150">2.5</td>
<td align="center" width="150">6</td>
<td align="center" width="150">1*</td>
<td align="center" width="150">1#*</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center" width="150">4</td>
<td align="center" width="150">6</td>
<td align="center" width="150">2.5</td>
<td align="center" width="150">1#*</td>
</tr>
<tr>
<td align="center" width="150">6</td>
<td align="center" width="150">6</td>
<td align="center" width="150">2.5</td>
<td align="center" width="150">1#*</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center" width="150">10</td>
<td align="center" width="150">6</td>
<td align="center" width="150">6</td>
<td align="center" width="150">2.5</td>
</tr>
<tr>
<td align="center" width="150">16</td>
<td align="center" width="150">6</td>
<td align="center" width="150">6</td>
<td align="center" width="150">2.5</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center" width="150">25</td>
<td align="center" width="150">16</td>
<td align="center" width="150">16</td>
<td align="center" width="150">6</td>
</tr>
<tr>
<td align="center" width="150">35</td>
<td align="center" width="150">16</td>
<td align="center" width="150">16</td>
<td align="center" width="150">6</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center" width="150">50</td>
<td align="center" width="150">16</td>
<td align="center" width="150">16</td>
<td align="center" width="150">6</td>
</tr>
<tr>
<td align="center" width="150">70</td>
<td align="center" width="150">50</td>
<td align="center" width="150">50</td>
<td align="center" width="150">16</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center" width="150">95</td>
<td align="center" width="150">50</td>
<td align="center" width="150">50</td>
<td align="center" width="150">16</td>
</tr>
<tr>
<td align="center" width="150">120</td>
<td align="center" width="150">50</td>
<td align="center" width="150">50</td>
<td align="center" width="150">16</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center" width="150">150</td>
<td align="center" width="150">50</td>
<td align="center" width="150">50</td>
<td align="center" width="150">16</td>
</tr>
<tr>
<td align="center" width="150">185</td>
<td align="center" width="150">70</td>
<td align="center" width="150">70</td>
<td align="center" width="150">50</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center" width="150">240</td>
<td align="center" width="150">70</td>
<td align="center" width="150">70</td>
<td align="center" width="150">50</td>
</tr>
<tr>
<td align="center" width="150">300</td>
<td align="center" width="150">70</td>
<td align="center" width="150">70</td>
<td align="center" width="150">50</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center" width="150">400</td>
<td align="center" width="150">70</td>
<td align="center" width="150">70</td>
<td align="center" width="150">50</td>
</tr>
<tr>
<td align="center" width="150">500</td>
<td align="center" width="150">70</td>
<td align="center" width="150">70</td>
<td align="center" width="150">50</td>
</tr>
<tr bgcolor="#b19aca">
<td align="center" width="150">630</td>
<td align="center" width="150">70</td>
<td align="center" width="150">70</td>
<td align="center" width="150">50</td>
</tr>
</tbody>
</table>
<p>* 1.5 sq mm where earth conductor in unenclosed<br /># 2.5 sq mm for bonding other services at entry to premises.</p>
<h2>DIAMETERS AND GLAND SIZES OF ARMOURED PVC INSULATED CABLES</h2>
<table width="100%" cellspacing="2">
<