28.01.2010
In this article we conclude our look at the new rules with a quick look at the rest of the changes in Part 6 and the new and changed special sections in part 7. Finally we will wrap up proceedings with a look at the new annexes that are contained in the 4th edition of ET101.
Continuing on from our last article clause 613.4 Detection of erroneous connections between circuits (fig 61.1a and 61.1b page 156 ET101) it is important that before we move on that I should highlight that there is also a change in Table 61A page 152 regarding the minimum value of insulation resistance permissible for separated extra low voltage (SELV) and Protected extra low voltage (PELV) circuits, minimum value is now 0.5 Meg-ohms. Circuits greater than ELV but less than or equal to 500V (including functional extra low voltage (FELV)), have a new minimum value of 1 Meg-ohm. In other words all minimum values of insulation resistance have been doubled.
In clause 613.13 Fault-loop impedance measurements the maximum values permissible have been reduced by ⅓. This is in order to take account of the heating effects of a fault current in the circuit concerned and is a CENELEC requirement. Up until now these values were based on cold values with no adjustment made for the heating effect of the fault current on the circuit in question.
In Chapter 62 Periodic Inspection and Testing there is considerable change introduced. This includes a new Periodic Inspection Report form which is displayed in Annex 62A. The form is designed to cater for the fact that it will often be given to non-technical people so there is an attempt to make the “key information” easy to interpret. Another feature of the report is that it is designed to get the person responsible for the filling in the report to follow a standard sequence of checks with minimal scope for “a personal approach”. The intent here is that Reports may be easily compared even though different people may be involved (reporting) over the lifetime of the installation. There is only one way to get to understand the information /design/ procedures associated with the document in question and that is to read the section concerned!
Chapter 63 deals with Certification and again there is much change here. In fact since the 4th Edition has been launched a number of additional changes have taken place which will necessitate the publication of an amendment to the Rules sometime early in 2010. These new changes are as a result of additional certification requirements that have been issued recently by the Commission for Energy Regulation. One such change covers an additional requirement concerning the record of post connection tests e.g. loop impedance and RCD verification tests. It is now mandatory for the electrical contractor to send the results of his/her post connection tests to their respective Regulatory Body within a specified time period following energisation of the electrical installation. The certification is considered incomplete until this part of the process is “completed”. There will be a new four part certificate published by ETCI to cover this new process. In the meantime electrical contractors will be expected to create an extra copy by photocopying their existing certificate and filling in the details required having completed the tests in question. The photo-copy can be sent to the appropriate Regulatory body in order to comply with the new requirement during the period before the new certificates appear on the system.
Annex 63A shows specimen completion certificates and Annex 63B gives guidelines for certification for alterations to existing installations. The definitions used here are also used by CER in their “Criteria” document for describing the requirements concerning “controlled works”. This chapter and associated Annexes cover quite a number of changes which because of their number are beyond the scope of this article. As previously stated the only way of keeping fully informed is to read the Chapter / Annexes concerned. In fact it is essential that the electrical contractor is completely familiar with the information concerned given the importance of the certification procedures.
Part 7 Requirements for Special Installations or Locations: The requirements of Part 7 supplement modify or replace the general requirements of the other parts of the Rules. There are a number of completely new part 7’s and a number of changes to existing part 7’s. Due to the limitations of space all I can describe for you is where the changes occur or give a brief description.
New Section 7’s: 702A: Fountains, 708: Caravan Parks (replacing the former 708 which included caravans), 709: Marinas, 710:Medical locations, 711: Exhibitions, Shows, and Fairs, 712: Solar photovoltaic power supply systems, 715: ELV lighting installations, 717: Mobile or transportable units, 721: Caravans and Motor Caravans, 740: Temporary installations for structures, amusement devices and booths, fairgrounds, circuses, 753: Floor and ceiling heating systems. Some changes that were made to the existing Part 7’s are as follows: 701: Bathrooms including a requirement for a dedicated 30mA RCD to protect all LV luminaires located within the zones including also 30mA RCD protection for all circuits within the zones the only exception being SELV circuits. 703: Saunas, changes to the zone dimensions. 704: Construction sites: Changes include 500mA RCD required for socket outlets exceeding 32A. 705: Agricultural and Horticultural Installations: Changes include 100mA RCD required for socket outlets exceeding 32A all other circuits require 300mA protection. Temperature marking of luminaires required in areas considered a high risk of fire hazard. Where high density livestock rearing exists automatic life-support systems must be provided.
Annexes are used in the Rules to provide additional information etc. They may be “normative” or “informative”. Normative means the annex is mandatory whereas an informative annex is not mandatory. There are a number of new annexes including: Annexe numbers 41A, 41B, 41C (various measures for protection against shock), 51E Multi core cable colours (summary), 52F summary of the rules for wiring concealed in walls and partitions. 53A RCD Additional information, 53B Protection of meter tails, 54A sizes and materials used for earth electrodes, 55A Final circuit arrangements (supersedes annex 43A of the third edition) contained within this annex is the new requirement that forbids the use of non-fused spurs. Already discussed are 62A Periodic report form, and 63A Examples of completion certificates, 753A Floor and ceiling heating systems: There are also a number of changes to existing annexes namely: Annex 52C Tables for armoured cable buried in ground have been added, 54B tables for the value of “K” previously located in chapter 54, 61A Visual Inspection has been expanded, 61C Determination of fault loop impedance by calculation (pre-connection only), 61F Verification of fault loop impedance values. Tables A61C- 1+2 reduced by ⅓ (already discussed).
Well that completes our look at the changes in this fourth edition of the Irish National Wiring Rules. I sincerely hope that with the help of the information contained in this and the previous five articles that you are now in a position to become conversant with the “new” requirements. This statement is made on the presumption that the reader is already familiar with the content of the third edition and of course has a copy of the new Rules!
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Source: Jim Keogh |
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