ISO INTERNATIONAL STANDARD 6858 Secondedition 2017-11-15 Aircraft Ground support electrical supplies General requirements Aéronefs - Alimentations électriques de service au sol des avions - Conditionsgeneralesrequises Reference number AX IS0 6858:2017(E) ISO @ IS0 2017 IS0 6858:2017(E) COPYRIGHTPROTECTEDDOCUMENT @IS02017,Published inSwitzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 [email protected] www.iso.org ii @ IS0 2017 - All rights reserved IS0 6858:2017(E) Contents Page Foreword Introduction. ..vi 1 Scope. 1 2 Normative references. .1 3 Terms and definitions 4 Technical basis. 5 Electrical characteristics 5.1 General. 5.1.1 Overview... 4 5.1.2 Alternating current (AC) power sources 5.1.3 Direct current (DC) power sources. 5 5.2 Interface connector. 6 5.3 Electromagnetic interference 6 5.3.1 Utility interface. 6 5.3.2 Aircraft interface 6 5.4 AC steady-state output characteristics. 6 5.4.1 General 6 5.4.2 Steady-state AC load characteristics 6 5.4.3 Steady-state AC voltage performance 7 5.5 AC transient characteristics... .8 5.5.1 General. 8 5.5.2 Transient AC load characteristics 8 5.5.3 Transient AC voltage 8 5.5.4 Transient frequency 9 5.6 DC steady-state output characteristics 9 5.6.1 Steady-state DC load characteristics. 9 5.6.2 Steady-state voltage 9 5.6.3 Voltage ripple 6 5.7 DC transient characteristics. 9 5.7.1 Transient DC load characteristics (other than engine start-related) .9 5.7.2 Transient DC voltage 9 5.7.3 Engine starting output characteristics. .10 6 Electrical protection .10 6.1 General. ..10 6.2 AC system protection. .10 6.2.1 Overvoltage. .10 6.2.2 Undervoltage .10 6.2.3 Frequency .10 6.2.4 Overcurrent and short circuits .10 6.2.5 Phase sequence. .11 6.2.6 DC content ..11 6.2.7 Open neutral/phase conductors .11 6.2.8 Earth/Ground fault. .11 6.3 DC system protection. .11 6.3.1 Overvoltage .11 6.3.2 Undervoltage .11 6.3.3 Reverse polarity .11 6.3.4 Reverse current. ..11 6.3.5 Overcurrent and short circuits .12 7 Control circuit and supply ..12 7.1 Control circuits. .12 7.2 Aircraft interlock supply for AC facilities .12 @ IS0 2017 - All rights reserved iii