HD 384.4.45 S1:1989

Electrical installations of buildings - Part 4: Protection for safety - Chapter 45: Protection against undervoltage

Concerns the precautions to be taken where a drop in voltage, or a loss and subsequent restoration of voltage could imply dangerous situations for persons or property or where a part of the installation or current-using equipment may be damaged by a drop in voltage.

Elektrische Anlagen von Gebaüden - Teil 4: Schutzmaßnahmen - Kapitel 45: Schutz gegen Unterspannung

Installations électriques des bâtiments - Partie 4: Protection pour assurer la sécurité - Chapitre 45: Protection contre les baisses de tension

Concerne les précautions à prendre lorsque la disparition de la tension et son rétablissement peuvent entraîner des dangers pour les personnes et pour les biens ou lorsqu'une partie de l'installation ou un matériel d'utilisation peut être endommagé par une baisse de tension.

Električne inštalacije zgradb – 4. del: Zaščitni ukrepi – 45. poglavje: Podnapetostna zaščita (IEC 60364-4-45:1984)

General Information

• Status: Published
• Publication Date: 08-Mar-1989
• Withdrawal Date: 30-Dec-1989
• ICS: 29.120.50 - Fuses and other overcurrent protection devices
• ICS: 91.140.50 - Electricity supply systems
• Technical Committee: CLC/TC 64 - Electrical installations and protection against electric shock
• Drafting Committee: IEC/TC 64 - IEC_TC_64
• Parallel Committee: IEC/TC 64 - IEC_TC_64
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 30-Aug-2023
• Completion Date: 23-Sep-2025
• Ref Project: SIST HD 384.4.45 S1:2000 - Electrical installations of buildings -- Part 4: Protection for safety -- Chapter 45: Protection against undervoltage (IEC 60364-4-45:1984)

Overview

HD 384.4.45 S1:1989 (aligned with IEC 60364-4-45:1984) addresses protection against undervoltage in electrical installations of buildings. The standard covers precautions to take where a drop in voltage, or a loss and subsequent restoration of voltage, could create dangerous situations for persons or property, or where parts of the installation or connected equipment may be damaged by voltage reduction.

This chapter is part of the broader HD 384 series on protection for safety and forms guidance for designers, installers and safety assessors responsible for building electrical systems and supply continuity.

Key Topics

• Scope and risk assessment: identifying circuits, equipment and locations where undervoltage or voltage restoration can cause hazards or equipment damage.
• Detection and monitoring: use of voltage monitoring and detection measures to identify drops or interruptions in supply.
• Protection measures: principles for implementing protective devices and strategies to prevent unsafe conditions when voltage falls below acceptable levels.
• Coordination with supply systems: considerations where supply characteristics or system faults may cause undervoltage across part or all of an installation.
• Restoration management: precautions for safe restoration of voltage after an interruption to avoid dangerous or damaging transients.

Practical keywords: undervoltage protection, voltage drop, electrical safety, building installations, supply monitoring, protective devices.

Applications

The guidance in HD 384.4.45 S1:1989 is relevant where undervoltage can affect safety or equipment integrity, including:

• Emergency and life‑safety systems (lighting, alarms)
• Medical and laboratory equipment sensitive to voltage variations
• Industrial control systems and motors vulnerable to undervoltage
• Data centers and communication equipment requiring stable supply
• Lifts, access control and security systems where unexpected restart or loss of function could create hazards

Common practical measures derived from the standard include installing voltage monitoring relays, alarm systems for loss or restoration of supply, coordinated protective schemes at distribution points, and use of alternative power sources (e.g., UPS, emergency supplies) where continuity is critical.

Related Standards

• IEC 60364 series - Electrical installations of buildings (general framework)
• IEC 60364-4-45:1984 - Protection against undervoltage (source equivalence)
• Standards on overcurrent and fuse protection (relevant for coordination of protection)
• Standards for power quality and supply continuity (for monitoring and mitigation measures)

By following HD 384.4.45 S1:1989, stakeholders can better assess undervoltage risks in buildings, specify appropriate monitoring and mitigation, and reduce the potential for harm to people and equipment without relying on site‑specific assumptions about voltage thresholds.

Standards Content (Sample)

SLOVENSKI STANDARD
01-februar-2000
(OHNWULþQHLQãWDODFLMH]JUDGE±GHO=DãþLWQLXNUHSL±SRJODYMH
3RGQDSHWRVWQD]DãþLWD,(&
Electrical installations of buildings -- Part 4: Protection for safety -- Chapter 45:
Protection against undervoltage (IEC 60364-4-45:1984)
Elektrische Anlagen von Gebaüden -- Teil 4: Schutzmaßnahmen -- Kapitel 45: Schutz
gegen Unterspannung
Installations électriques des bâtiments -- Partie 4: Protection pour assurer la sécurité --
Chapitre 45: Protection contre les baisses de tension
Ta slovenski standard je istoveten z: HD 384.4.45 S1:1989
ICS:
29.120.50 9DURYDONHLQGUXJD Fuses and other overcurrent
PHGWRNRYQD]DãþLWD protection devices
91.140.50 Sistemi za
...