Amendment 2: Draft For Public Comment

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.  

411.3.3

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.

421.1.7

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.

514.12

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.