IS:10101 Bitesize Guide from Hager

IS:10101 details the latest requirements for electrical installations in Ireland and comes into effect on the 1st of October 2020. We have created this bitesize guide, which outlines the principle changes to these wiring regulations, how they will affect you and what you can do to prepare.

 I.S.10101 Regulations

The draft version of I.S.10101 was issued on 3rd November 2018. The final version was published by NSAI in March 2020 and will come into effect on 1st October 2020. It is the latest in a series of documents giving the requirements for electrical installations.

Installations designed after 1st October 2020 are to comply with I.S.10101. The Regulations apply to the design, erection and verification of electrical installations, also additions and alterations to existing installations. Existing installations that have been installed in accordance with previous editions of the Regulations may not comply with this edition in every respect. This does not necessarily mean that they are unsafe for continued use or require upgrading.

The following are some of the main changes included in the new Regulations. 

Clause 411.3.4 Additional requirements for circuits with luminaires

“Additional protection by an RCD with a rated residual operation current not exceeding 30 mA shall be provided for a.c. final circuit supplying luminaires in domestic premises. Precautions should be taken to ensure that a fault of one circuit does not leave the installation hazardous.” 

In practice these requirements can be met by installing a consumer unit fitted with two RCDs. A mix of socket and lighting circuits can then be protected by each RCD to ensure redundancy in the installation.

Clause 421.1.7 

Protection against fire caused by electrical equipment

“It is recommended that special measures be taken to protect against the effects of arc faults in final circuits:

  • 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, wood-working shops, stores of combustible materials);
  • in locations with combustible constructional materials, i.e. CA2 locations (e.g. wooden buildings);
  • in fire propagating structures, i.e. CB2 locations; and
  • in locations with endangering of irreplaceable goods.” 

IS:10101 introduces a new kind of protection device – an Arc Fault Detection Device (AFDD). This device is specifically to detect and disconnect dangerous electrical arcs in both the fixed wiring and the connected equipment which could be the source of a fire.

An electrical arc could be a series arc (damage to or improperly terminated conductors) or parallel arc (damage to insulation) in nature. Should the arc reach certain parameters, the device will disconnect, extinguishing the arc and preventing a fire.

Arc fault detection devices conforming to IEC 62606 are recommended by I.S.10101 as a means of providing additional protection against fire caused by arc faults in AC final circuits. 

Part 443 

Protection Against Transient Overvoltages of Atmospheric Origin or Due to Switching

Previously the requirements to provide surge protection devices or not was rather complex, requiring consideration of keraunic (lightning) activity level at the location of the installation. This has been revised, and I.S.10101 now requires surge protection to be fitted in the following circumstances;

443.4 Overvoltage control

“Protection against transient overvoltage shall be provided where the consequence caused by overvoltage affects:

  1. human life, e.g. safety services, medical care facilities; 
  2. public services and cultural heritage, e.g. loss of public services, IT centres, museums; commercial or industrial activity, e.g. hotels, banks, industries, commercial markets, farms, a large number of individuals, e.g. large buildings, offices, schools. 

For other cases a risk assessment is required to be performed. Should a risk assessment not be performed then protection against transient overvoltage is required.” 

Single dwelling units however require an assessment as to whether the total value of the installation and equipment therein justifies the inclusion of such protection. 

531.3.3 Types of RCDs 

“RCD types AC are not recommended in new electrical installations. 

– RCD Type AC: RCD tripping on alternating sinusoidal residual current, suddenly applied or smoothly increasing. 

– RCD Type A: RCD tripping on alternating sinusoidal residual current and on residual pulsating direct current, suddenly applied or smoothly increasing. 

– RCD Type F: RCD for which tripping is ensured as for Type A and in addition: 
i) for composite residual currents, whether suddenly applied or slowly rising intended for circuit supplied between phase and neutral or phase and earthed middle conductor; 
ii) for residual pulsating direct currents superimposed on smooth direct current. 

– RCD Type B: RCD for which tripping is ensured as for Type F and in addition: 
a) for residual sinusoidal alternating currents up to 1 000 Hz; 
b) for residual alternating currents superimposed on a smooth direct current; 
c) for residual pulsating direct currents superimposed on a smooth direct current; 
d) for residual pulsating rectified direct current which results from two or more phases; 
e) for residual smooth direct currents whether suddenly applied or slowly increased independent of polarity.” 

RCDs exist in various different forms and react differently depending on the presence of DC components or different frequencies, and these are outlined in Clause 531.3.3. To fully comply with this clause it is essential to select the correct type of RCD for the application. 

Distribution Boards in domestic premises 

Clause 530.6.1 General 

“Distribution boards (switchgear assemblies) shall comply with I.S. EN 61439-1. 

Distribution boards and similar switchgear assemblies within domestic (household) premises, shall comply with I.S. EN 61439-3 and shall: 
i) have their enclosure manufactured from metallic or non-metallic materials complying with IEC 60695-2-11:2000, and the enclosure should be sized to take account of the equipment contained within, and the resulting internal ambient temperature rise, as per I.S. EN 61439-1.” 

In order to fully comply with Clause 530.6.1 it is essential that the enclosure materials used in domestic consumer units meet the glow-wire test requirements of IEC 60695-2-11, also the dimensions of the assembly, and the layout of the internal components, must meet the ambient temperature rise requirements of I.S. EN 61439-1. Assemblies conforming to these harmonised standards should be CE marked. 

The I.S.10101 standard is the first major revision to the wiring regulations in over 10 years, and is based on the IEC Harmonised document IEC 60364 for the safety of electrical installations. Full copies of the new standard can be ordered online from NSAI. 

For further information visit our IS:10101 Regs Hub at