IEC TS 60079-47:2021

Explosive atmospheres - Part 47: Equipment protection by 2-wire intrinsically safe ethernet concept (2-WISE)

IEC 60079-47:2021(E), which is a technical specification, specifies requirements for the construction, marking and documenting of apparatus, systems and installations for use with the 2-Wire Intrinsically Safe Ethernet concept (2-WISE), such as the physical layer specification for 2-Wire Ethernet 10BASE-T1L as defined in IEEE 802.3cg.
2-WISE is a concept for an advanced physical layer (APL), designed to simplify the examination process for intrinsic safety parameters of components and cabling within APL segments. This is achieved by defining universal intrinsic safety parameter limits for APL ports, according to the specific hazardous area requirements and listing a concise set of rules for the segment setup.
The requirements for construction and installation of 2-WISE devices and systems are included in IEC 60079-11, IEC 60079-14, and IEC 60079-25, except as modified by this document. Parts of a 2-WISE device can be protected by any Type of Protection listed in IEC 60079-0 appropriate to the EPL for the intended hazardous area. In these circumstances, the requirements of this technical specification apply only to intrinsically safe circuits of the apparatus.
Where a requirement of this document conflicts with a requirement of IEC 60079-0, IEC 60079 11, IEC 60079-14 or IEC 60079-25, the requirements of this document take precedence.

General Information

• Status: Published
• Publication Date: 02-Feb-2021
• ICS: 29.260.20 - Electrical apparatus for explosive atmospheres
• Technical Committee: SC 31G - Intrinsically-safe apparatus
• Drafting Committee: MT 60079-47 - TC 31/SC 31G/MT 60079-47
• Current Stage: PPUB - Publication issued
• Start Date: 03-Feb-2021
• Completion Date: 23-Feb-2021

Overview

IEC TS 60079-47:2021 - “Explosive atmospheres - Part 47: Equipment protection by 2‑wire intrinsically safe Ethernet concept (2‑WISE)” specifies construction, marking and documentation requirements for electrical apparatus, systems and installations that implement the 2‑Wire Intrinsically Safe Ethernet concept (2‑WISE). 2‑WISE is an Advanced Physical Layer (APL) approach based on 10BASE‑T1L (IEEE 802.3cg) that standardizes intrinsic‑safety parameter limits at APL ports to simplify intrinsic‑safety assessments for components and cabling in hazardous areas.

Key topics and technical requirements

• Scope & precedence: Applies to 2‑WISE devices and systems; where it conflicts with IEC 60079‑0, ‑11, ‑14 or ‑25, this document takes precedence for intrinsically safe circuits.
• Port classification: Defines port types - power source ports, power load ports, communication‑only ports, and auxiliary device ports - with specific requirements for each.
• Electrical limits for power source ports:
  • Nominal maximum output voltage: 14 V to 17.5 V (sum of DC and communication voltages under IEC 60079‑11 conditions).
  • Maximum internal capacitance and inductance: ≤ 5 nF and ≤ 10 µH.
  • Maximum output current: ≤ 380 mA.
  • Maximum output power: ≤ 5.32 W.
• Power load and auxiliary port parameters (per Table 1):
  • Max input voltage 17.5 V, max input current 380 mA, max power 5.32 W.
  • Max internal capacitance 5 nF; inductance 10 µH (power load) and 200 nH (auxiliary).
  • Maximum leakage current limits (e.g., 1 mA for load, 50 µA for auxiliary).
• Installation, documentation and marking: Requires descriptive system documents, schedule drawings, specific marking examples and compliance with IEC 60079‑11/‑14/‑25 where not modified.
• Design constraints: When internal termination networks introduce capacitance, effective capacitance limits and series‑resistor protection (example: ≤ 2.2 µF when protected by ≥ 90 Ω) are required.

Practical applications and users

• Who uses it:
  • Manufacturers of intrinsically safe Ethernet devices and APL equipment.
  • Process automation vendors and system integrators designing fieldbus/Ethernet segments in hazardous areas.
  • Plant electrical engineers in oil & gas, chemical, pharmaceutical, and mining sectors.
  • Test laboratories and certification bodies assessing intrinsic safety compliance.
• Practical value:
  • Enables single‑pair Ethernet (10BASE‑T1L/APL) deployments with simplified intrinsic‑safety assessment via universal port limits.
  • Facilitates power+data on two‑wire segments for remote field instruments while meeting explosion‑protection requirements.
  • Reduces complexity of certifying multi‑vendor segments by standardizing port parameters and segment setup rules.

Related standards

• IEC 60079 series (especially IEC 60079‑0, ‑11, ‑14, ‑25) - normative references.
• IEEE 802.3cg / 10BASE‑T1L - physical layer basis for APL and 2‑WISE.

Keywords: IEC TS 60079-47:2021, 2-WISE, 2‑Wire Intrinsically Safe Ethernet, APL, 10BASE‑T1L, intrinsically safe, explosive atmospheres, hazardous area, intrinsic safety parameters.

Standards Content (Sample)

IEC TS 60079-47 ®
Edition 1.0 2021-02
TECHNICAL
SPECIFICATION
Explosive atmospheres –
Part 47: Equipment protection by 2-wire intrinsically safe Ethernet concept
(2-WISE)
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IEC TS 60079-47 ®
Edition 1.0 2021-02
TECHNICAL
SPECIFICATION
Explosive atmospheres –
Part 47: Equipment protection by 2-wire intrinsically safe Ethernet concept

(2-WISE)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.260.20 ISBN 978-2-8322-9317-1

– 2 – IEC TS 60079-47:2021  IEC 2021
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Requirements for 2-WISE devices . 6
4.1 General . 6
4.2 2-WISE power source ports . 7
4.3 2-WISE power load ports and 2-WISE auxiliary device ports . 7
4.4 2-WISE communication only ports . 8
4.5 Simple apparatus . 8
5 Requirements for 2-WISE systems . 8
5.1 General . 8
5.2 Wiring systems . 9
5.3 Powered 2-WISE systems . 9
5.4 Communication only 2-WISE systems . 9
5.5 Descriptive system document . 10
6 Schedule drawings and instructions for 2-WISE devices . 10
7 Marking . 11
7.1 General . 11
7.2 Examples of marking . 11
Bibliography . 14

Figure 1 – DC-powered 2-WISE system . 9
Figure 2 – Communication only 2-WISE system . 10

Table 1 – Intrinsically safe parameters for 2-WISE Power load ports and auxiliary
device ports . 7
Table 2 – Intrinsically safe parameters for 2-WISE communication only ports . 8

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EXPLOSIVE ATMOSPHERES –
Part 47: Equipment protection by 2-wire intrinsically
safe Ethernet concept (2-WISE)

FOREWORD
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Technical specifications are subject to review within three years of publication to decide whether
they can be transformed into International Standards.
IEC TS 60079-47, which is a technical specification, has been prepared by subcommittee 31G:
Intrinsically safe apparatus, of IEC technical committee 31: Equipment for explosive
atmospheres.
– 4 – IEC TS 60079-47:2021  IEC 2021
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
31G/323/DTS 31G/334/RVC
Full information on the voting for the approval of this technical specification can be found in the
report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60079 series, published under the general title Explosive
atmospheres, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
EXPLOSIVE ATMOSPHERES –
Part 47: Equipment protection by 2-wire intrinsically
safe Ethernet concept (2-WISE)

1 Scope
This part of IEC 60079, which is a technical specification, specifies requirements for the
construction, marking and documenting of apparatus, systems and installations for use with the
2-Wire Intrinsically Safe Ethernet concept (2-WISE), such as the physical layer specification for
2-Wire Ethernet 10BASE-T1L as defined in IEEE 802.3cg.
2-WISE is a concept for an advanced physical layer (APL), designed to simplify the examination
process for intrinsic safety parameters of components and cabling within APL segments. This
is achieved by defining universal intrinsic safety parameter limits for APL ports, according to
the specific hazardous area requirements and listing a concise set of rules for the segment
setup.
The requirements for construction and installation of 2-WISE devices and systems are included
in IEC 60079-11, IEC 60079-14, and IEC 60079-25, except as modified by this document. Parts
of a 2-WISE device can be protected by any Type of Protection listed in IEC 60079-0
appropriate to the EPL for the intended hazardous area. In these circumstances, the
requirements of this technical specification apply only to intrinsically safe circuits of the
apparatus.
Where a requirement of this document conflicts with a requirement of IEC 60079-0,
IEC 60079-11, IEC 60079-14 or IEC 60079-25, the requirements of this document take
precedence.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60079-0, Explosive atmospheres - Part 0: Equipment - General requirements
IEC 60079-11, Explosive atmospheres - Part 11: Equipment protection by intrinsic safety "i"
IEC 60079-14, Explosive atmospheres - Part 14: Electrical installations design, selection and
erection
IEC 60079-25, Explosive atmospheres - Part 25: Intrinsically safe electrical systems
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60079-0,
IEC 60079-11, IEC 60079-14, IEC 60079-25 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp

– 6 – IEC TS 60079-47:2021  IEC 2021
3.1
10BASE-T1L
physical layer standard for 10 Mb/s Ethernet communication over a single balanced twisted-
pair copper cabling with optional provision of power
Note 1 to entry: This is standardized in IEEE 802.3cg.
3.2
Advanced Physical Layer
APL
physical layer based on 10BASE-T1L
3.3
2-Wire Intrinsically Safe Ethernet
2-WISE
...