Traditionally, most underground structures have been bonded in common to reduce hazardous voltages associated with lightning strikes and induced man made currents in the earth or to provide an economical and low resistance ground for power systems. The National Electrical Code calls for use of an underground metallic water pipe as the primary grounding electrode.1  Cathodic protection of an entire downtown underground system has been attempted with limited success.2  With the advent of cathodic protection, the underground network begins to change. Cathodically protected structures must be isolated or insulated away from other underground structures in order to achieve the necessary negative voltage shift at a reasonable current flow from the power source.

Subject
Electric current, Piping, Electrochemical cells, Voltage, Cathodic protection, Pipelines, Grounding, Cables, Equipment, Health, safety, and environment, Electrolytes, Concentration cells, Polarization cells
© 1974 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
1974
Association for Materials Protection and Performance (AMPP)
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