Date / Document / Project Nr.
16 April 2013 / ER G12/4
All Comments from Public Consultation – Review group comments added
Line
number / Clause/ Subcl-ause / Parag-raph Figure/ Table / Type
of comment (General/ Technical/
Editorial) / COMMENTS / Proposed change / OBSERVATIONS OF THE SECRETARIAT
on each comment submitted
2 / General / The UK lighting board(UKLB) agree that there has in the past been a lack of consistency in the type of connection provided at similar sites to due to differing interpretations of the existing requirements by different DNO engineers. From that perspective the UKLB welcome an initiative to clarify the regulations. / Suggest this section identifies the benefits to all consumers (and not just ‘Rail’) of these amendments / Not accepted. The benefits are in improved guidance on special situations; update the documents in line with changes in standards since the last revision and closer alignment with the IET wiring regulations.
2 / General / There is no economic appraisal of this revision. Will UKplc benefit overall? What are the projected additional costs for DNOs and customer? / There should be an economic appraisal of the revision such that there is clarity about the changes in terms of overall cost and the cost to individual parties. This should form part of an sustainability assessment / Not accepted. There have been no significant changes to the technical requirements so the revision is cost neutral.
2 / General / There is no environmental appraisal of this revision. Will implementation require more or less materials? (I am assuming line losses will remain constant, but this should also be assessed from a Carbon emissions point of view|) / There should be an environmental appraisal of the revision such that there is clarity on the environmental impact of the proposed changes. This should form part of an sustainability assessment / Not accepted. There have been no significant changes to the technical or material requirements with the result that the revision does not have an environmental impact.
2 / General / There is no societal impact appraisal of this revision. Will implementation result in a greater or reduced level of safety overall. (From a UKLB perspective, there is a concern that consideration has not been given to the possibility there may be an overall increase in risk to our workforce, see below) / There should be a societal impact appraisal of the revision such that there is clarity on the overall safety impact of the proposed changes. This should form part of an sustainability assessment / Not accepted. There have been no significant changes to the technical or installation requirements with the result that the revision does not have social impact
36 / E / Should this reference be explicit that it does or does not include 2011 Amendment 1 to the wiring regs? / Accepted. The draft was commenced prior to Amendment 1, which is why it is not referenced. Add reference.
36/37 / 2 / E / Remove reference to edition to future-proof document / Delete ‘Seventeenth Edition’ / Not accepted, 17th editioncontained the current regulations at the time of the review.
52 / 3 / E / General comment. Lack of consistency in the framing of definitions. Some definitions start with ‘A’ or ‘An’. Others times do not when they could / Provide consistent approach / Not accepted. The minor differences arise because the definitions are taken from different reference documents. This is explained in the note.
52 / 3 / T / The abbreviation ABC is used in several places in the draft. This term may not be familiar to readers not from a supply / distribution company background / Provide a definition of Aerial bundled cable (ABC) / Accepted in principle. Align with definition from standards for aerial bundled conductor. BS 7870-5 or TS 43-13may have a definition.
56 / 3 / E / Add date as future versions of BS 7671 may be amended. / Make ‘BS 7671: 2008 (2011)’ / Accepted.
70 / T / You apply a different meaning to the term ‘caravan’ to that given in BS 7671 / Clarify that you use a different definition of caravan to that used in BS 7671 / Not accepted. This is already clarified by the note, i.e. the definition would have a double asterisk if taken from BS 7671.
77 / 3 / E / The word ‘they’ could be misunderstood / Replace ‘they are’ with ‘the mobile home or residential park home is’ / Not accepted, the wording seems sufficiently clear.
109 / 3 / E / It is stated that the definition of ‘marina’ has been taken from BS 7671 but wording is different / Change second line to read
‘pontoon arrangements capable of berthing one or more pleasure craft’ / Accepted in principle – the full BS 7671 (2011) definition will be used.
123 / 3 / E / The ‘e’ in ‘earth’ should be capitalised to align with the definition of Protective Multiple Earthing in BS 7671 / Capitalise the ‘e’ in ‘earth’ / Accepted.
162 / 3 / E / Typo / Replace’ narthed’ with ‘earthed’ to read
‘…or combined neutral / earthed sheath return wiring…’ / Accepted.
168 / 3 / E / This note is not helpful as it gives only one example of how the metallic path might be provided (the metallic path would be different in, for example, an overhead line forming part of the supply network in a TNS system). / Delete the note / Not accepted – the note is for illustrative purposes only.
198 / T / This clause should also include the requirement defined in ESQCR Reg 7 (1) / Include text of Reg 7 (1) / Accepted in principle. Add generalised text summarising ESQCR Reg 7(1) regarding continuity.
202 / T / Does this mean that all services will have 16mm services or greater? Smaller services have been used on street furniture previously. / Accepted that some clarification is needed. Add “recommended” before “minimum values”. This document is not intended to apply retrospectively.
203 / 4.3.1 / T / The supply arrangement description is unclear. / With reference to Section 312 of BS7671, replace ‘single phase three wire (split phase)’ with ‘two-phase 3 wire, phase angle 180°’ / Accepted in principle. Add note at end of paragraph but keep original text as this is usual terminology.
205 / 4.9 / E / Line not phase / Replace ‘phase’ with ‘line’, to read ‘line conductors’. / Not accepted. “Line” and “phase” have a particular meaning with reference to a 3 phase system.
206 / 4.3.1 / T / The supply arrangement description is unclear / With reference to Section 312 of BS7671, after ‘two phase three wire’ add ‘phase angle 120°’ / Accepted in principle. Add note at end of paragraph but keep original text. See earlier comment on line 203.
208 / 4.3.1 / E / Line not phase / Replace ‘phase’ with ‘line’, to read ‘line conductor’. / Not accepted. See earlier comment on line 205.
209 / 4.3.1 / E / Given the confusion / lack of clarity with regard to the descriptions of supply conductor arrangements mentioned in previous comments, we recommend inclusion of circuit diagrams to illustrate supply conductor arrangements / Include circuit diagrams similar to those in section 312 of BS 7671 to illustrate supply conductor arrangements / Not accepted. The notes were added so adiagram wouldnot be needed.
231 / T / Is a neutral connection required on both sides of the connection, if just one, which should provide it? / To comply with the Regulations just one earth is required and would normally be on the DNO side but by agreement can be on either side. No change in wording proposed.
243 / The abbreviation CNE is used in several places in the draft. This term may not be familiar to all readers / Either provide a definition of ‘Combined neutral and earth (CNE)’ or state term fully (as above) at first usage in document / Accepted.This will be explained on the first occurrence in the document.
280 / Figure 4.4 / technical / Since 2003 TfL have installed for all traffic signals an earth electrode at the feeder pillar to ensure PME service is made available and to minimise danger to public. / Include customer earth electrodes on diagrams and consider the additional contribution towards safety of a PME network. / Not accepted. Fig 4.4 shows minimum requirements to be compliant.
283 / Fig 4.5 / And elsewhere / Font issues. Text overwriting / Amend text / Accepted. Text will be checked and corrected as appropriate
283 / Fig 4.5 / Line not phase / Replace ‘phase’ with ‘line conductor’ to read ‘line conductor normally open’ / Not accepted. See earlier comments on line 205.
327 / 4.9 / Amend title to include bonding, conductors which are also referred to in this section / Amend title to read ‘Type and size of earthing and bonding connections’ / Accepted.
332 / T / BS will not apply to all cases covered in the document / Add ‘where applicable’ after ‘BS 7671’ / Accepted in principle. Re-word to, “as shown in Table 4.9a” and remove reference to BS7671 here.
338 / 4.9 / Table 4.9a / E / In row 2 of table, should read line not phase / Make ‘line conductor’ / Not accepted.See earlier comment on line 205.
338 / 4.9 / Table 4.9a / T / The requirement stated in row 5, right-hand column of table can be more onerous than BS7671 requirement, which is given in Regulation 542.3.1. There is no apparent technical justification for this. / Amend to read ‘See BS 7671’ / Accepted. Also, delete “company’s” from rows 4&5
344 / E / The table commences at 35mm – what about smaller services? / It might be clearer to include a top line saying “less than 35mm … with 16mm earth” / Not accepted. The current table is aligned with other reference documents. The table refers to typical sizes of three-phase cables.
347 / 4.10 / E / What is meant by earthing leads? / Provide clarification of, or definition of, ‘earthing lead’ / Accepted. Change to “earthing conductors”
369 / T / Worth considering/incorporating reference to ESQCR Reg 24 (4) & (5) as replacement of services are included in scope / Accepted in principle. Reference to these Regulations will be made in the Appendices but not here.
377 / 5.1 / T / The text here is too vague. Limit the rise of potential to what? / Provide further clarification of this statement / Accepted. Change to, “sufficient to control the rise of potential to acceptable levels under open-circuit neutral conditions, having considered the requirements of BS EN 60479-1.” Add BS EN 60479-1 to references section.
383 / 5.1 / ‘TT installation’ is technically incorrect / Amend to ‘installation forming part of a TT system’ / Accepted.
383 / T / Where customer needs to convert to a TT installation, does the Distributor pay for the customer works? / This is a technical document and does not address commercial issues. No change proposed.
384 / 5.1 / T / Any electrode and RCD(s) provided would have to meet the relevant requirements of BS 7671 / Add ‘in accordance with the requirements of BS 7671’ after ‘earth electrode and fitting an RCD’ / Accepted in principle but see next comment on line 384
384 / 5.1 / T / With reference to previous comment on line 384, provision of a single RCD may not be sufficient to comply with BS 7671 / Amend to read ‘…a separate earth electrode and fitting one or more RCDs installed in accordance with the requirements of BS7671’ / Accepted. Change to “appropriate protection in accordance with BS7671 (eg an RCD).”
390 / 5.1 / T / There is no such thing as ‘earth bonding’ / Replace ‘earth bonding’ with ‘earthing and bonding’ / Accepted.
391 / Current wording is in adequate / Replace ‘a suitable earth electrode and RCD should be installed’ with ‘a separate earth electrode and one or more RCDs should be installed in accordance with the requirements of BS7671 to provide fault protection’ / Accepted in principle – replace “RCD” with, “Appropriate protection in accordance with BS 7671”
391 / T / Where customer needs to convert to a TT installation, does the Distributor pay for the customer works? / This is a technical document and does notaddress commercial issues. No change proposed.
410 / T / This has caused considerable debate in the gas industry as the reason for insulated inserts are not understood by them. Insulated inserts are not always provided, or installed. Who pays the GT for an insulated insert to be fitted? / The insulated insert prevents current returning through metallic gas infrastructure which would provide a parallel earth return path if not fitted. This requirement was already in G12/3 Figure 3. No change proposed.
This is a technical document and does notaddress commercial issues.
423 / 5.2.3 / T / BS 951 clamps should not be applied to the outside of cables.
BS951 Part 1 (Scope) Note 1 states
‘…such clamps (as specified in BS 951) are not intended for connection to the armour or sheath of a cable / We suggest that another means of connection is found / used recommended / Accepted, although it is only the tests from the BS that were referenced. A more appropriate reference will be substituted.
424 / T / Is this the correct BS? The link seems to indicate that a constant force clamp is essential. Clarity is required regarding whether earth clamp connectors to lead sheath are permitted on DNO supply cables, as it is prohibited by the NICEIC and ESC as part of BS951:2009 and the 17th Ed. Regs - 512-05-01. / Accepted. See previous comment
435 / 5.3 / Note / T / ‘Line’ not ‘live’ A neutral conductor is also a live conductor / Amend to read ‘If the line and neutral conductors are …’ / Accepted in principle. Change “live” to “phase”
440 / G / Meter Operators frequently find cut-outs which are not labelled as PME. When ENA asked on ER requirement the response was that the ER only used the term “should” which means the distributor does not always have to place a label. This leaves the method of earthing available to a customer ambiguous. This is a serious concern for meter operators who are left uncertain what type of earthing (if any) is provided to the customer / On all new and service alterations or cut-out changes the distributor should always explicitly label every cut-out to identify the type of earthing available: CNE, SNE or no earth available. The meter operator and/or customer representative can then connect (or not) to the distributor provided earth connection. This is particularly important when connecting customers in ‘special situations’ / Not accepted,asthis is not considered practical. It is the policy of most Network Operators to fit a label. If uncertain of the earthing arrangement, acompetent person should be contacted
447 / 6.1 / E / The word ‘very’ is unnecessary / Delete ‘very’ / Accepted.
447 / 6.1 / 1stpara / Editorial / Use oftheword“very” asin“very
satisfactory” isavaluejudgement. Satisfactoryissufficient / Delete“very” before“satisfactory” / Accepted.
451 / 6.1 / E / Wording around use of TT earthing is not correctly expressed / Reword to read ‘… an alternative form of fault protection such as conversion to a TT system earthing arrangement consisting of an earth electrode and one or more RCDs installed in accordance with the requirements of BS 7671’ / Accepted in principle. Review in line with comments on lines 384 and 391.
451 / Technical / This doesn’t mention the UKPN practice of using a grading electrode to raise the potential of the surrounding ground thus reducing the touch potential to the earthed metalwork.
Practically, installing a 70mm2 bare copper electrode 500mm deep and 500 around the perimeter of a feeder pillar is difficult in a London street. The clause seems to force the customer to use Class2 feeder pillar to get PME earth. However, A class 2 pillar will not offer any safety to earth metalwork beyond the feeder pillar even if an RCD is used. / Include the practice of using UKPN “grading electrode” or not / Not accepted. As this is a National Document it cannot include the practices of all Network Operators - they will each have their own earthing policy based on this generic document and tailored for their specific requirements.
458 / 6.1 / Note / BS 7671 contains requirements and only rarely provides guidance. / Reword to read ‘Specific requirements on various specialised installations can be found in BS 7671’ / Accepted (use “requirements for”).
461 / Technical / Perhaps traffic signals could be included in special conditions. It is possible for a traffic signal controller, being intelligent equipment, to disconnect it load and reduce the risk of dangerous potential on all associated earthed metalwork. / ADD
Intelligent equipment.
Where equipment includes voltage monitoring or similar such that under neutral fault conditions the connected load may be reduce to less than 500w in 0.4sec. / Not accepted. Whilst this may be an interesting technical solution the technology is currently unproven for use for this specific purposeso it cannot yet be included in National Documentation.
475 / T / May wish to make explicit that this applies to cut-out and meter panels. Meter panels are provided by distribution businesses.
Clarity requested with regard to bullet (c) – is this with regard to railways only or in general on every PME supply position. If general; this is an issue as most multi-occupancy site positions have metal MSDBs (i.e. BEMCO, Ryefield) so many sites would not be compliant. / Include explicit reference to meter panels / Not accepted. This is part of sub-clause 6.2.1, which relatesonly to railways and tramways.
486-490
501–526 / 6.2.1.2 b) / General / The statement that ‘The requirements for earthing of electrical installations on AC electrified systems are governed by BSEN 50122-1 and the Railway Group Standard GL/RT1255’ is potentially misleading.
This statement gives the impression that the aforementioned standards apply universally to all locations where ac electrified railways are present in the UK. However, the UK rail sector has a number of distinct entities (infrastructure managers, depot operators, manufacturer’s maintenance facilities, freight facilities etc.) whose technical standards might differ.
Consequently, it is unwise to make such a generalisation using specific reference to standards which may or may not apply on a mandatory basis.
Furthermore, so far as the Railway Group Standards (RGS) are concerned, (i) GL/RT1255 is not the main document so far as protective provisions for the traction system is concerned, (ii) these RGS documents are scope limited and do not apply (as a mandatory standard) to all locations on the UK rail network, (iii) these RGS documents are subject to on-going change as a result of factors such as progressive implementation of European Technical Specification for Interoperability.
Consequently, the text needs to be more generalised and avoid reference to specific standards and arrangements.
Reference to specific standards should be on an ‘entity specific’ basis, contained in Appendix 2, and be linked to their specific mandatory requirements. / Reword line 486-490 to read:
The requirements for earthing of electrical installations on railway lines with AC electrification are governed by railway sector design standards. These standards can result in higher touch voltages than are permitted on the PME network.
Delete lines 501 – 526.
Add a cross reference to Appendix 2.
Insert in Appendix 2, entity specific mandatory standards and requirements. / Accepted in principle but there is a need to keep relevant information currently in lines 486-500.
Figures and text beyond line 500 will be removed.
References to specific railway standards will not be normative in this document.
Appendix 2 is already referenced.
568 / 6.2.2 / The word ‘temporary’ seems superfluous / Delete the word ‘temporary’ / Not accepted. The supply may be for the final installation or a future one
589 / 6.2.2.3 / T / Why is an isolating transformer (which provides protective separation between the input winding(s) and output
winding(s)) necessary? Won't any suitable power transformer providing simple separation be sufficient? / Reconsider requirements / Accepted in principle. Delete section 6.2.2.3.