In some situations, electrical supply may be wired but not particularly stable or reliable. If you are using computer equipment in places where electricity current fluctuates, you may need surge protectors. Backup precautions (duplicate equipment, manual means of doing equipment tasks) are essential where power upsets are likely.

Voltage can vary between countries (see Varying Standards / I4).

Written by Nadia McLaren, Union of International Associations, with revisions and HTML layout by Robert Pollard, Information Habitat: Where Information Lives.