L_V_Circuit_Breakers - Federal Elektrik - #49

Text version of the page

Untitled table.main {} tr.row {} td.cell {} div.block {} div.paragraph {} .font0 { font:6.00pt "Arial", sans-serif; } .font1 { font:7.00pt "Arial", sans-serif; } .font2 { font:8.00pt "Arial", sans-serif; } .font3 { font:16.00pt "Arial", sans-serif; } .font4 { font:17.00pt "Arial", sans-serif; } .font5 { font:34.50pt "Arial", sans-serif; } .font6 { font:5.00pt "Arial Black", sans-serif; } .font7 { font:12.00pt "Georgia", serif; } .font8 { font:14.00pt "Georgia", serif; } .font9 { font:9.00pt "Impact", sans-serif; } .font10 { font:15.00pt "Lucida Sans Unicode", sans-serif; } .font11 { font:7.00pt "Palatino Linotype", serif; } .font12 { font:13.00pt "Trebuchet MS", sans-serif; } .font13 { font:28.00pt "Trebuchet MS", sans-serif; } .font14 { font:8.00pt "Verdana", sans-serif; } .font15 { font:9.00pt "Verdana", sans-serif; } .font16 { font:10.00pt "Verdana", sans-serif; } LV. CIRCUIT BREAKERS Calculation of short circuit at any point of Ihe network: The following tables allow fast calculation of the short circuit curreni at any point in the network, ïf short circuit currenl at network side, cable section, type and length are known Readlng of diagram: Cable section and short circuit current on network side is marked in the table Cable length is found on ihe cable section row. Cable length and shon circuit curreni at network side are intersected and marked. This value gives the short circuit current to occur at the end of the cable 380 V ■115 V Cable (mm2) Cu Al Câbla length (m) 1.5 2,5 — — 1 — — 2 — 3 2.5 4 — — 1 — — 2 3 4 5 4 6 — 1 — — 2 3 4 6 8 6 10 1 — — 2 3 4 6 9 12 10 16 1 2 — 3 5 7 10 15 20 16 25 2 — 3 S 8 1t 16 24 32 25 35 3 4 5 6 13 18 25 38 50 35 50 4 5 ? 11 18 25 35 53 70 50 70 5 8 10 15 25 35 50 75 too 70 120 7 11 14 21 35 49 70 105 t40 120 185 12 18 24 36 60 95 120 143 180 190 240 150 240 13 20 26 39 65 130 195 260 185 300 15 23 30 46 77 154 231 308 240 19 28 38 57 96 192 283 284 300 24 36 46 72 120 240 360 480 lac network l*Aï lac Shorl circuit currenl at Isc load side (kA) 100 65 51 42 30 19 10 7 ? 10 62 49 41 29 19 10 7 5 80 58 47 39 29 18 10 7 5 70 52 44 37 28 18 10 6 5 M 47 40 35 27 18 9 6 5 41 36 32 25 17 9 6 5 45 38 34 30 24 17 9 6 5 40 35 32 28 23 16 9 6 5 35 31 28 26 21 16 9 6 1 30 25 27 23 25 22 23 20 20 18 IS 14 9 9 6 6 5 5 » rafc 11 9 6 5 15 14 14 13 12 11 9 7 6 4 10 10 10 9 9 8 7 6 5 4 7 7 7 7 6 6 5 5 4 3 5 5 5 5 5 4 4 3 3 4 4 4 4 4 4 3 3 3 2 Cable (mm*) Cu Al Cable lengm (m) 1.5 2.5 — — — — 1 — 2 3 5 « 4 — — — 1 2 3 4 '6 8 4 6 — — 1 2 3 3 4 4 6 8 12 6 10 - 1 2 6 9 13 19 10 16 — 2 3 5 7 10 15 20 30 16 25 2 3 5 e t» 16 24 32 48 25 35 4 5 8 13 17 25 38 50 75 35 50 5 7 11 18 24 35 53 70 105 50 70 9 12 18 30 42 60 69 120 179 70 120 11 15 23 38 53 75 113 151 226 95 150 14 19 29 48 66 95 143 190 285 120 185 18 24 36 60 84 120 180 240 360 150 240 19 26 39 65 91 130 195 ?f.Z 391 462 185 300 23 30 46 77 107 154 231 306 240 28 38 57 96 134 192 288 384 576 300 36 48 72 120 168 240 360 460 720 lac network OcA) lac Short clrcull currenl al Isc load side (kA) 100 45 •40 25 20 12 8 5 4 3 N 45 35 25 20 12 8 S 4 3 '60 45 35 25 15 12 6 5 '4 3 70 40 35 25 15 12 S 5 4 3 60 40 35 25 15 12 8 5 4 3 H 35 30 25 15 12 8 5 4 3 45 35 30 25 15 12 8 5 4 3 ■10 30 30 25 15 12 8 5 4 3 35 30 25 20 15 ta 6 5 4 3 30 25 25 20 15 10 7 5 .4 3 25 25 20 20 12 10 7 5 4 3 22 22 20 17 12 10 7 5 4 3 15 15 15 12 10 6 5 4 3 10 10 10 10 a 1 6 4 3 2 7 7 6 6 6 5 4 4 3 2 S 5 5 4 4 4 3 3 2 2 4 4 4 4 3 3 3 2 2\ 2 Example: A value (67m) lower than 70 m cable length is selected on the row corresponding lo 95 mm? cable (Cu) section in 380V panel Short circuit current to occur is found as 11 kA by intersection this column with ihe row giving a higher value fisc 22 kA) of Ihe 20 KA shon circuit current al network direction. Short circuil breaking capacity of ihe circuit breaker to be used at Ihis point should be higher than (Icu) 11 kA. <> FEDERAL ï/14