Amendment 2: Draft For Public Comment

This article gives a brief summary of the important changes affecting electrical designers and installers.  It is important to note however that any or all of this information is subject to change depending on the comments received on the draft.  

Amendment 2

18th Edi­tion Wir­ing Reg­u­la­tions

Amendment 2

Amend­ment 2 to the 18th edi­tion wir­ing reg­u­la­tions BS 7671 is due for pub­lic­a­tion in 2022.  At the time of writ­ing this art­icle it is in the ‘Draft for pub­lic com­ment’ phase.  This lit­er­ally means what it says; any­one in­ter­ested can read the draft copy and make com­ments.  In or­der to do this you will need to log onto the BSI web­site.  This is open and avail­able un­til 11th Decem­ber 2020.  After this time the panel re­spons­ible for the con­tent of the doc­u­ment (known as JPEL/64) go through all the com­ments made and make ad­just­ments if re­quired to the fi­nal doc­u­ment.  The fi­nal doc­u­ment will be­come  BS 7671:2018 Amend­ment 2 on 28th March 2022.


This art­icle gives a brief sum­mary of the im­port­ant changes af­fect­ing elec­trical de­sign­ers and in­stallers.  It is im­port­ant to note however that any or all of this in­form­a­tion is sub­ject to change de­pend­ing on the com­ments re­ceived on the draft.  Not every al­ter­a­tion, ad­di­tion or de­le­tion is covered and should you wish to see the whole doc­u­ment this is avail­able as stated on the BSI web­site.


The first change is to do with the im­ple­ment­a­tion date. Con­ven­tion­ally there has been a 6 month trans­ition period whereby in­stall­a­tions de­signed after a cer­tain date are to com­ply with the new edi­tion.  This was to al­low for large pro­jects with an ex­ten­ded design and in­stall­a­tion phase.  There has al­ways been some am­bi­gu­ity with this however es­pe­cially with re­peat in­stall­a­tions like hous­ing de­vel­op­ments.  The new word­ing says ‘Elec­trical in­stall­a­tions, the erec­tion of which is com­menced after 28th March 2023, are to com­ply with BS 7671:2018 in­cor­por­at­ing Amend­ment 2:2022’  This should there­fore re­move this am­bi­gu­ity.  Amend­ment 2 is still not ret­ro­spect­ive like pre­vi­ous edi­tions so there is no need to up­grade any ex­ist­ing in­stall­a­tion.  Ad­di­tions however to an ex­ist­ing in­stall­a­tion will be re­quired to com­ply with amend­ment 2 re­quire­ments after 28th March 2023.  Also, Elec­trical In­stall­a­tion Con­di­tion Re­ports will have to be car­ried out to amend­ment 2 re­quire­ments after 28th March 2023.  



Ad­di­tional pro­tec­tion by RCD, not ex­ceed­ing 30mA is re­quired for socket out­lets and for mo­bile equip­ment up to 32A used out­doors.  An ex­cep­tion was per­mit­ted for a socket out­let in an in­stall­a­tion other than a dwell­ing if a doc­u­mented risk as­sess­ment could de­term­ine that the RCD was not ne­ces­sary.  This ex­cep­tion has been de­leted so every socket out­let up to 32A re­gard­less of where it is or what it will be used for will re­quire ad­di­tional pro­tec­tion by RCD.


This is to do with Arc Fault De­tec­tion Devices (AF­DDs).  The 18th edi­tion gave a re­com­mend­a­tion for their use in cer­tain in­stall­a­tions.  The new reg­u­la­tion says; ‘Arc fault de­tec­tion devices (AFDD) con­form­ing to BS EN 62606 shall be provided for single-phase AC fi­nal cir­cuits sup­ply­ing socket-out­lets and fixed cur­rent-us­ing equip­ment with a rated cur­rent not ex­ceed­ing 32A’ And
‘AF­DDs are re­com­men­ded for all other fi­nal cir­cuits’. There are some sug­ges­ted cir­cuits where they may be omit­ted as un­ex­pec­ted dis­con­nec­tion could cause danger.  One such in­stance is ‘light­ing cir­cuits in dwell­ings’.


Sec­tion 443

This sec­tion con­cerns Over­voltage pro­tec­tion via the use of Surge Pro­tec­tion Devices (SPDs).  Presently there are 4 in­stances where surge pro­tec­tion devices shall be used and a risk as­sess­ment to de­term­ine whether SPDs shall be used for all other in­stall­a­tions.  Single dwell­ing units are not in­cluded and is up to the owner whether they wish to have SPDs in­stalled based on a cost jus­ti­fic­a­tion of in­stalling them against the cost of the equip­ment they are there to pro­tect.  Amend­ment 2 has just 2 in­stances where SPDs shall be in­stalled, where an over­voltage could res­ult in:
(i) ser­i­ous in­jury to, or loss of, hu­man life;
(ii) sig­ni­fic­ant fin­an­cial or data loss

Other cases will re­quire the risk as­sess­ment cal­cu­la­tion to be per­formed.  This cal­cu­la­tion is the same for­mula i.e   CRL = fenv / (Lp x Ng).  If the res­ult of this for­mula pro­duces a CRL ≥ 1000 then Pro­tec­tion against tran­si­ent over­voltages of at­mo­spheric ori­gin is not re­quired.Es­sen­tially the same rules ap­ply to single dwell­ing units, there is however a note of warn­ing (Note 5) say­ing that most equip­ment is of over­voltage cat­egory level I or II which is po­ten­tially at risk from tran­si­ent over­voltages.



This reg­u­la­tion re­quires no­tices such as the RCD test­ing and Peri­odic In­spec­tion in­form­a­tion to be af­fixed to a dis­tri­bu­tion board.  For con­sumer units in do­mestic in­stall­a­tions this has for a while been an is­sue as the Build­ing Reg­u­la­tions re­quire the con­sumer unit to be ac­cess­ible.  This has res­ul­ted in the con­sumer unit be­ing in­stalled in places such as hall­ways and in plain sight.  For this reason man­u­fac­tur­ers have taken great care in en­sur­ing their con­sumer unit is aes­thet­ic­ally pleas­ing as pos­sible and even of­fer­ing flush boards.  Then to com­ply with BS 7671 sev­eral stick­ers are usu­ally placed on the front face.  These are not wanted by the homeowner so are of­ten re­moved.  Amend­ment 2 re­cog­nises this and says the stick­ers need not now be ap­plied to do­mestic premises as long as the Guid­ance for Re­cip­i­ents as part of the Elec­trical In­stall­a­tion Cer­ti­fic­ate is given which con­tains this re­quired in­form­a­tion. 

531.3.3 Types of RCD

The 18th edi­tion made us more aware of the ex­ist­ence of dif­fer­ent types of RCDs for dif­fer­ent pro­tec­tion re­quire­ments.  Type A RCDs have es­sen­tially be­come the norm since but type AC devices  still ex­ist but have lim­ited use.  The state­ment in 18th edi­tion that says ‘For gen­eral pur­poses, Type AC RCDs may be used’  has been altered to say ‘For gen­eral pur­poses, only Type A RCDs may be used’. And then it goes on to say ‘Type AC RCDs shall only be used to serve fixed equip­ment, where it is known that the load con­tains no DC com­pon­ents’  Some ex­amples of this type of equip­ment are then given.

Chapter 54 Earth­ing ar­range­ments & pro­tect­ive con­duct­ors

There is quite a ma­jor ad­di­tion with a new reg­u­la­tion 542.1.2.202.  This calls for new premises con­struc­ted on found­a­tions to have some kind of found­a­tion earth elec­trode or sim­ilar.  This is if ADS is used as the method of pro­tec­tion against elec­tric shock which is very likely.  This elec­trode shall have a value of res­ist­ance to earth not ex­ceed­ing 20Ω and shall be re­quired to be con­nec­ted to the Main earth­ing Ter­minal via a main pro­tect­ive bond­ing con­ductor.


Part 8

There is a brand new part (part 8) and Chapter 82.  This is to do with Prosumer’s elec­trical in­stall­a­tions (PEI).  A prosumer is newly defined in part 2 as an ‘En­tity or party which can be both a pro­du­cer and a con­sumer of elec­trical en­ergy’   This new Chapter provides re­quire­ments for PEIs to achieve safe op­er­a­tion, sus­tain­ab­il­ity and ef­fi­cient use of en­ergy when in­teg­rated into smart grids.