I.S. 10101 Summary of Key Changes

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The NSAI will publish the 5th Edition National Rules for Electrical Installations, IS 10101:2020 (hereafter “the new standard”) on 6 March 2020. This replaces the 4th Edition, ET 101:2008 (hereafter “the old standard”).

Below are summary of the key changes, as highlighted by NSAI:

I.S. 10101 – General

The layout and structure of the document differs from the current Wiring Rules. For example, what were previously known as “Parts” (i.e. Parts 1-7) in ET 101:2008 are being re-labelled as “Chapters” in I.S.10101:2020. This change will serve to enhance readability of the document into the future.

I.S. 10101 – Chapter 1: Scope

Chapter 1 is largely unchanged.  The scope includes the fixed wiring installation right up to the electric socket or isolator. The requirements for appliances connecting into electrical sockets, or wired into isolators, are covered by separate standards, and not by the National Rules for Electrical Installations.

The document includes more detailed information on design of electrical installations and so will a very useful reference for design teams.

I.S. 10101 – Chapter 2: Definitions

Definitions are now all contained in Chapter 2 to enhance readability. The definitions list has been expanded and certain definitions have been modified to align with the definitions provided in the International Electrotechnical Vocabulary.

I.S. 10101 – Chapter 3: General Characteristics

This section has been expanded to cover different supply and earthing arrangements.

 I.S. 10101 – Chapter 4: Protection for Safety

Clause 411.3.4

Residual Current Devices (RCDs) will now be required to be installed on lighting circuits in domestic premises.

Clause 421.7

Arc Fault Detection Devices (AFDDs) will now be recommended for circuits installed in locations with particular risk, such as:

  • in premises with sleeping accommodation;
  • in locations with risks of fire due to the nature of processed or stored materials, i.e. BE2 locations, (e.g. barns, woodworking shops, stores of combustible materials);
  • in locations with combustible constructional materials, (example = wooden buildings);
  • in fire propagating structures;
  • in locations with endangering of irreplaceable goods.

I.S. 10101 – Chapter 5:

Selection and Erection of Equipment

Clause 512.1.5 Compatibility

The above Clause will require, on request, a sign off by the appropriate person, that the installation complies with the Electromagnetic Compatibility (EMC) Directive 2014/30/EU. This applies only to the fixed wiring and switchgear, and not to any appliance connected after the isolator or socket.

Clause 527 Selection and Erection of wiring systems to minimise the spread of fire

The Clause requires all cables, as a minimum, to be rated Class Dca-s2, d2, a2 in accordance with I.S. EN 50575.

Clause 531.3.3 Types of RCD’s

Residual current devices (RCDs) Type AC are not recommended in new installations.

Clause 534 Devices for protection against overvoltage

This is a completely new section; which provides details on the selection of Surge Protection Devices (SPDs) including wiring diagrams, especially where lightning protection will be installed in a building.

I.S. 10101 – Chapter 6:

Verification and Certification

Chapter 6 has been completely revised to align with the European Standard. Model certificates have now been removed. As previously mentioned, CRU now oversees the inspection and verification process, and certificates are issued by Safe Electric. It is necessary to highlight that certification will transition to an online format and it is for this reason model certificates are no longer included in the Standard.

I.S. 10101 – Chapter 7: Special Installations or Locations

The associated CENELEC 60364 series of HDs have been updated and this is now reflected in I.S. 10101:2020

Part 710 Installations in Medical Locations

Part 710 has been revised to reflect changes in the European requirements (HD 60364-7-710:2012) and contains several changes including:

• Clause 710.411.6.3.101

Now requires an assessment of “other electrical equipment” before being used in the patient environment.

• Clause 710.415.2.2

Now requires the resistance of supplementary protective bonding conductors in group 1 as well as group 2 medical locations, to not exceed 0.2 Ohms.

• Clause 710.554.101

Now requires the intended use of a medical location to be considered when deciding on the number of socket outlets to be protected by a single RCD.

• Clause 710.554.102

Now requires that socket outlets of medical IT systems in group 2 locations be un-switched, coloured blue, and clearly and permanently marked “Medical Equipment Only”.

Part 712 Photovoltaic systems

The requirements for these systems have expanded significantly.

Part 722 Supplies for Electric Vehicles

Charging for Electric Vehicles was published as an amendment to ET 101:2008 in 2017. This section is now consolidated as Part 722 in Chapter 7 and is largely unchanged from the version released previously in ET 101:2008/A3:2018.

Part 730 Onshore Units of Electrical Connections for Inland Navigation Vessels

This section is entirely new.

Energy efficiency (Annex 8)

This section is entirely new and provides recommendations and guidelines on design and erection of electrical installations to optimise energy, including metering, load control and minimisation of losses in conductors.


Implementation of I.S. 10101

The CRU has decided on a transition period of 24 months to enforce compliance with the new standard. The following applies to all restricted and controlled electrical works in either commercial or domestic properties.

For more information around the implementation dates, please visit this page.