电气装置中的人员与设备保护措施

5.1.3 Protection by extra low voltage

Equipment of safety class II and type-tested assemblies with total insulation are identified with the symbol □ as per DIN 40014.

Conductive parts within the enclosure must not be connected to the protective conductor, otherwise it will be a device in safety class I. If protective conductors must be routed through insulated equipment, they must be insulated like live conductors.

Exceptions

Measures for protection in case of indirect contact are not required for the following equipment:

• lower parts of overhead line insulators (except when they are within reach)
• steel towers, steel-concrete towers, packing stands
• equipment that is not likely to come into contact by any part of the human body because of its small dimensions (e.g. 50 mm x 50 mm) or because of its configuration,
• metal enclosures for protection of equipment of safety class II or equivalent.

As per DIN VDE 0100-410 (VDE 0100 Part 410) the use of the SELV and PELV extra low-voltage systems (Fig. 5-6) can offer protection in case of direct and indirect contact. Extra low voltages in accordance with these specifications are AC voltages ≤ 50 V and DC voltages ≤ 120 V. Corresponding specifications for current circuits with limited discharge energy (≤ 350 m J) are in preparation.

Current sources for supplying extra low-voltage systems of the SELV and PELV types must be safely separated from the infeed system, e.g. as isolating transformer with shielding (DIN EN 60742 (VDE 0551) or as motor generators (DIN VDE 0530), but not as autotransformer, potentiometer and the like.

The SELV extra low voltage, apart from secure separation of the current circuits, requires that neither live parts nor metallic enclosures must be earthed. Protective measures to prevent direct contact, such as barriers, enclosures or insulation are not necessary here if the rated voltage does not exceed AC 25 V and DC 60 V.

Live parts and metallic enclosures may be earthed with the PELV extra low voltage. Protective measures against direct contact are also not necessary here with rated voltages below AC 25 V and DC 60 V, if metallic enclosures, which can be touched simultaneously, and other conductive parts are connected to the same earthing system.

The FELV extra low voltage is supplied by a power source without a safe isolation. Earthing the current circuits is permitted. Metallic enclosures must be connected to the protective conductor on the primary side of the power source. Protection against direct contact and in case of indirect contact is generally required (DIN VDE 0100-470 (VDE 0100 Part 470).

Auxiliary circuits in switchgear installations are often operated with extra low voltage. With reference to protection in case of indirect contact, the systems with safe isolation (SELV, PELV) are to be recommended, particularly with small direct cross sections, because in contrast to the FELV system, no additional measures are required. Consistent safe isolation from the supply network must be assured by the selection of the equipment in the entire current circuit.

6

2 Scope

2

EUROPEAN STANDARD

NORME EUROPÉENNE

EUROPÄISCHE NORM

EN 10216-3

May 2002

ICS 23.040.10; 77.140.75

English version

Seamless steel tubes for pressure purposes –
Technical delivery conditions

Part 3: Alloy fine grain steel tubes

Tubes sans soudure en acier pour service sous pression – Conditions techniques de livraison – Partie 3: Tubes en acier allié à grain fin

Nahtlose Stahlrohre für Druckbeanspruchungen – Technische Lieferbedingungen – Teil 3: Rohre aus legierten Feinkornbaustählen

This European Standard was approved by CEN on 2002-04-25.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Management Centre or to any CEN member.

The European Standards exist in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, and the United Kingdom.

CEN

European Committee for Standardization

Comité Européen de Normalisation

Europäisches Komitee für Normung

Management Centre: rue de Stassart 36, B-1050 Brussels

© 2002. CEN – All rights of exploitation in any form and by any means reserved worldwide for CEN national members.

Ref. No. EN 10216-3 : 2002 E

Contents

Section	Page
Foreword	3
Introduction	4
1 Scope	4
2 Normative references	5
3 Definitions	5
3.1 DN	5
3.2 PN	5
4 Designations	6
4.1 Range of PN designations	6
4.2 Range of DN (nominal sizes)	6
4.3 Gasket types	6
4.4 Information to be supplied by the purchaser	6
5 Gasket designs	6
6 Gasket types	7
7 Dimensions	7
8 Marking	10
Annex A (informative) Information to be supplied by the purchaser	10
Annex B (informative) A-deviation	11

:current

Foreword

This document (EN 10216-3:2002) has been prepared by Technical Committee EC/TC 29, "Steel tubes and fittings for steel tubes", the secretariat of which is held by UNI.

This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by November 2002, and conflicting national standards shall be withdrawn at the latest by November 2002.

This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s).

For relationship with EU Directive(s), see informative annex ZA, which is an integral part of this document.

Other Parts of EN 10216 are:

Part 1:	Non-alloy steel tubes with specified room temperature properties
Part 2:	Non-alloy and alloy steel tubes with specified elevated temperature properties
Part 4:	Non-alloy and alloy steel tubes with specified low temperature properties
Part 5:	Stainless steel tubes

Another European Standard series covering tubes for pressure purposes is:

EN 10217:

Welded steel tubes for pressure purposes

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.

5

1 Scope

This Part of EN 10216 specifies the technical delivery conditions in two test categories for seamless tubes of circular cross section, made of weldable alloyed fine grained steel.

2 Normative references

This European Standard incorporates by date or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For date references, subsequent amendments to or revisions of, any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments).

The requirements of this European Standard rule when they differ from those in the standards and documents referred to below:

EN 10002-1, Metallic materials - Tensile testing - Part 1: Method of test (at ambient temperature).

EN 10002-5, Metallic materials - Tensile testing - Part 5: Method of testing (at elevated temperature).

EN 10020, Definitions and classification of grades of steel.

EN 10021, General technical delivery requirements for steel and iron products.

EN 10045-1, Metallic materials - Charpy impact test - Part 1: Test method.

EN 10052, Vocabulary of heat treatment terms for ferrous products.

EN 10204, Metallic products - Types of inspection documents.

EN 10027-1, Designation systems for steels - Part 1: Steel names, principle symbols.

EN 10027-2, Designation systems for steels Part 2: Numerical systems.

ENV 10220, Seamless and welded steel tubes - Dimensions and masses per unit length

EN 10233, Metallic materials - Tubes - Flattening test.

EN 10234, Metallic materials - Tubes - Drift expanding test.

EN 10236, Metallic materials - Tubes - Ring expanding test.

EN 10237, Metallic materials - Tubes - Ring tensile test.

EN 10246-1, Non-Destructive Testing of steel tubes Part 1: Automatic electromagnetic testing of seamless and welded (except submerged arc welded) ferromagnetic steel tubes for verification of hydraulic leak-tightness.

EN 10246-5, Non-Destructive Testing of steel tubes - Part 5: Automatic full peripheral magnetic transducer/flux leakage testing of seamless and welded (except submerged arc-welded) ferromagnetic steel tubes for the detection of longitudinal imperfections.

EN 10246-6, Non-Destructive Testing of steel tubes - Part 6: Automatic full peripheral ultrasonic testing of seamless steel tubes for the detection of transverse imperfections.

EN 10246-7, Non-Destructive Testing of steel tubes - Part 7: Automatic full peripheral ultrasonic testing of seamless and welded (except submerged arc welded) steel tubes for the detection of longitudinal imperfections.

6