Summary of changes in BS7671:2018 DPC

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This is a list of the changes between the 17th edition and the new 18th DPC, numbered in the order that they appear in the document.

The DPC is now available for download as a PDF file, which is much easier to use and can be searched through, unlike the online system. Download from the same place as the online version.


Part 2 new definitions:
Combined short circuit current capability
Combined short circuit protection
Conditional short circuit current
Continuity of service
Control and protective switching device
Co-ordination of electrical equipment
Departure
Energy efficiency
Foundation earth electrode
Inland navigation vessel
Non-compliance
Overcurrent protective device
Partial selectivity
Short circuit current rating
Short circuit protective device

Part 4
411.3.1.2 NEW - Metallic pipes entering the building having an insulating section at their point of entry need not be connected to the protective equipotential bonding
411.3.2.1 Additions re. device suitable for isolation of at least the line conductor, new Note re. IT systems on 1st/2nd fault disconnections
411.3.2.2 Additionally applies to 63A with 1+ socket outlet
Table 41.1 Disconnection time for DC 120-230V changed (was 5, now 1)
Note 2 New note, disconnection provided by RCD, refers 411.4.4 411.5.3 411.6.5
411.3.2.5 Wording changed completely
411.3.2.6 Deleted, automatic disconnection/supplementary bonding. See new 419.
411.3.3 Exceptions for no RCD on socket outlets deleted, all socket outlets now require RCD
411.4.2 Note changed from 'may additionally be connected ..' to a reference to 542.1.201 which now requires connection to an earth electrode in TN systems
411.4.3 Added 'no switching or isolating device shall be inserted in the PEN conductor'
411.4.4 Previously content in 411.4.5. New Note 2, fault currents in TN systems when RCDs used
411.4.5 Previously content in 411.4.4 Amended ref 531.2.9 > 536.4.1.6. Changed 'discrimination' to 'selectivity'.
411.4.201 Previously content in 411.4.6
411.4.203 Previosuly content in 411.4.8
411.4.204 Previously content in 411.4.9
411.5.1 Additional text re. neutral point/mid point being earthed.
411.6.1 Some rewording, new Note 2
411.6.2 No longer applies to DC systems, note explains why
411.6.3 2 new Notes, RCD capacitive leakage, and faults in different devices
411.6.3.1 Deleted - see new 411.6.4
411.6.3.2 Deleted - see new 411.6.4
411.6.4 Various changes, some content from 411.6.3.1/2 included here
411.6.5 Various changes to layout, notes, etc
412.1.2 Content from 412.1.3 with revisions
412.1.3 Deleted - most content now in 412.1.2
413.3.3 Minor change to text, meaning unchanged
414.1.2 Minor change to note, locations -> cases
414.4.5 (iii) and (iv) are now (i) and (ii) after 'basic protection is generally..'
415.2.2 Lines now numbered (i) and (ii), previously not numbered. Minor change to text, meaning unchanged
419 All new, provisions where automatic disconnection is not feasible (also ref old deleted 411.3.2.6)
421.1.7 New - arc fault detection devices may be used
422.2.1 'wiring systems in escape routes as short as possible' deleted. Changes - other standards for cable, add euroclasses for reaction to fire, smoke production, etc.
422.3.4 change to ref. euroclass eca standards, various other minor changes to standards for cables etc.
422.4.203 changed from comply with BSEN60332-1-2 to comply with 422.2.1
440.2 Content now in a table, content unchanged
443 All significantly rewritten and expanded, substantial new content, plus annexes
46 Isolation and Switching All new. Similar content was in previous 16th edition. Also see 53

 

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Part 5
512.1.5 New note 4, current rating tables to be used/not used
514.4.5 Now has i,ii,iii - was green not used, now green not used for live, protective, functional earth/bonding
521.10.202 New - wiring systems supported so they do not collapse in fire,
Notes 1,2,3 all new, non metallic clips, NM cable trunking not permitted / steel or copper clips saddles ties are examples which meet requirements
Replaces 521.11 which covered escape routes only - now applies to all cables
Table 52.3 New note 4, Lighting circuits 1.0mm cable - 'for lighting circuits and associated small power using equipment, ' some attempt at clarification of what a lighting circuit is?
527.1.3 Changes to references standard and Euroclass
530 Scope changed, does NOT cover 'requirements to provide compliance with measures of protection and safety'. Most of the rest significantly rewritten, far less text than in previous version
531 Significantly changed and rewritten, substantial amount of new material added
532 Expanded/rewritten, new sections on AFDDs, IMDs etc.
533.1 Renumbered compared with 17th. Most content unchanged
533.1.1 Additional info on ICBs and aM aR fuses
533.1.3 Additional text Annex H of BSEN60942-2 and IT systems
533.2.1 New Note to clarify definitions used
533.2.2 New Note refers to Appendix 4
534.1 New, lightning protection zones
534+ Substantially changed section on SPDs and using them
535 Undervoltage - totally rewritten and expanded
536 Coordination of protective devices - totally rewritten and significantly expanded. Many pages of new material
537.1.1 2 new Notes, motor control switching inrush etc.
537.1.2-6 Changed, much removed, probably incorporated elsewhere
537.2 - 537 end Significant changes, rewritten and renumbered completely.
538 Note: is missing, previously explained what Monitoring is. 538+ various changes to text and numbering.
Annex A53 All new, Devices and associated functions, several pages
542.2.2 Previously 542.2.3, New Note 2, BS7430
542.2.3 New regarding foundation earth electrodes
542.2.8 New, connections between parts of earth electrodes
543.3.3.101 Expanded, previously 543.3.3
543.3.3.102 Expanded, previously 543.3.3
559.10 New, ground recessed luminaires, BSEN60598-2-13 (PREVIOUSLY 714.512.3)

Part 6
61,62,63 All deleted, moved to 64+ with revisions
641.1 'precautions shall be taken...' deleted (old 610.1)
642.3 addition of c.i and ii = akternative sources, choice/setting of protective & monitoring devices
addition of xvii selection erection of wiring
addition of xix selection installation of SPDs
addition of xx electromagnetic disturbances
addition of 'include particular requirements for special installations Part 7
643.2 continuity - deleted 'inc main/supp bonding conductors', replaced with 'conns to ECPs'. Deleted specs for 200mA and 4-24V DC, now has 'measurement of resistance', added testing live conductors for ring circuits (L&N), 2.2 separate continuity of rings deleted
643.3.2 added 'FELV circuits shall be tested ...' after table 64. Deleted old 612.3.4 which covered same. Added 'When measured values show evident differences between circuits, further investigation to identify the reasons is required.'
old 612.4.5 Basic protection by barrier/enclosure DELETED (would have been new 643.4.5)
643.6 i Polarity - q/ 463.1.2 control device for lighting circuits switching neutral, see Fig 46.1
old 612.7 Earth Electrode resistance - deleted and replaced with new 643.7.2 which now allows resistance to be calculated rather than measured.
643.7.1 a 1 added alternative option for measuring resistance of protective conductors and calcs of EFLI rather than measurement. a 2 additional text for RCDs, disconnection fault current, disc times, proving by continuity of cps. (same for b 2)
643.7.1 c Substantially changed/rewritten.
643.7.3 EFLI - several additional lines - continuity test, bonding checked, etc.
643.8 Additional protection - added section re. supplementary bonding
643.10 Function testing - added some examples of equipment. Added 'protective devices shall be submitted to a test of their function as necessary' which implies testing of circuit breakers is required.
643.11 Voltage drop - significantly condensed to cover measurement or calculation only.
644 Certification for IV - some content from old 63, various alterations and additions.
651.2 Periodic insp/test - added iii and iv - confirm rating/setting of protective/monitoring devices
added note - existing installations, prev editions, not unsafe etc
added - insulation resistance not required if RCM or IMD installed & RCM/IMD functioning shall be verified (what is the method of verification?)
653 Reporting for periodics - some content from old 63, various additions/changes - more detail than previously

Part 7
704.410.3.6 added - electrical sep. of supply for more than one piece of eqpt is not permitted
704.512.2 added - external influences
704.522.8.101 added - cables across roads / walkways, surface run and overhead cables
704.56 added - safety services, no info - note only?
705.422.7 changed 'for fire protection' to 'for additional fire protection'. Note about protection with RCDs for fire DELETED
708.1 added note 3 - elec installations of residential park homes
708.313 changed 'shall be 230/400v' to 'not exceed 230/400v', added '48V DC'
708.415.1 added, additional protection & RCDs. Socket outlets individually protected, 30mA, disc all live conductors
708.512 expanded with more detail, ext influences AG moved to 705.512.2.1.3
708.512.2 External influences note added.
708.521.7 Rearranged although content substantially identical.
708.53+ Substantially rearranged and content revised.
710.411.3.2.5 ii and Table 710 DELETED (maximum disconnection times)
710.415.2.1 'supplementary equipotential bonding connection points ...' revised to be available in group 2 and considered for group 1.
New Note 2 on number of points to be considered. (Previously this reg gave minimum numbers of points)
710.512.1.2 new note on guidance in HTM 06-01
714.512.3 Ground recessed luminaires - DELETED (NOW IN 559.10)
715.524.201 Amended from 3 listed points to more general text description
721.413 new - electrical separation
721.414 new - SELV/PELV
721.415.1 new - additional protection RCD
721.544.1 new - protective bonding conductors
721.55.2.1 deleted / not used (previously required lv socket outlets to have an earth contact)
A721.528.2.5 Substantially expanded, cables and LPG installations. (old A721.528.3.4)
A721.533.1.5 added 'in all cases upstream of the distribution circuits'
A721.55.3.5 added '... tray sufficient to hold 20% ...'
722.1 Reworded although content is not changed
722.411.4.1 PME for charging vehicles: Some changes to existing text. Main change is that for dwellings the exception for 'reasonably practical' has been deleted.
722.411.4.201 Street electrical fixtures - DELETED (was a note only and somewhat redundant as covered in 722.411.4.1 anyway)
722.511.101 new - charge stations to comply with BSEN 61851 series
722.512.2.202 new - solid bodies AE
722.512.2.203 new - impact AG
722.531.2.101 expanded - covers type of RCDs for charge stations and standards to comply with
722.531.2.1.1 RCDs shall disconnect all live conductors (previously part of 822.531.2.101)
722.533 new - overcurrent protection devices
730 & A730 All new - onshore units of electircal shore connections for inland navigation vessels
753.1 Heating - scope amended, now includes wall heating, outdoor heating and more.
753.411.3.2 Note amended - ref to capacitance and manufacturer deleted, now refers just to leakage current. New note - class II heating units do not requrie metallic grids as in 753.411.1
753.412 New - double or reinforced insulation
753.413 New - electrical separation not permitted for wall heating
753.415.1 add - time delayed RCDs not permitted
753.423 add - reference to CENELEC guide 39 for floor temperatures
753.424.101/102 New - content replaces 753.424.3, protection on overheating
753.512 Deleted - operational conditions / external influences
753.514 Documentation, some requirements deleted, capacitance, heated area etc
753.515 prevention of mutual detrimental influence - revised and expanded
753.515.5 deleted - required manufacturers instructions to be followed
753.522.4.3 Minor change, deleted text about informing other contractors
753.544 New - current using equipment

Part 8 All new, energy efficiency

 

[securespark]

If you still wanted (for example) a freezer to go on a non-RCD protected supply, could you run a radial to an FCU and connect the appliance directly to it? Would a 13A breaker with a flex outlet on the end comply?

 

[JohnW2]

If you still wanted (for example) a freezer to go on a non-RCD protected supply, could you run a radial to an FCU and connect the appliance directly to it?

The proposed 411.3.3 relates only to socket outlets (and portable equipment used outdoors), and I can find no requirement (in 415.1 or elsewhere) for RCD protection of circuits in which the load is connected directly or via an FCU (other than in bathrooms etc., where all circuits have to be RCD protected).

It would therefore seem that you would still be able to do as you describe - i.e. have a freezer (or, indeed, any other load) connected via an FCU without having to have RCD protection. Indeed, if it were a dedicated circuit with an OPD sufficiently low-rated to protect the cable (e.g. a B10 or B16), you wouldn't even need an FCU - a switch or other means of direct connection would seem to be acceptable.

411.3.3 does, of course, relate to any sockets with a rated current up to 32A, not just BS1363 ones. It therefore presumably would require RCD protection of, say, 2A/5A sockets in lighting circuits.

Kind Regards, John