Amendment 4 (2026) to BS 7671:2018 IET Wiring Regulations.

Sparkingchip said:

So, it is time to start planning ahead.

My first question is it a new book? There seems to be a lot of additional information and possibly changes as well.

There is no official information at the moment. However, lots of changes usually means the best approach is an updated 'book'.

Sparkingchip said:

There is a third question, which is when the 19th Edition is being published, which presumably will require new books and an exam, but I assume that won’t be published for at least two years?

We don't know the answer to that question yet. 

gkenyon said:

When you write down the cover colours and try to order them, there is no pattern at all really.

This is certainly possible to do, if you have prior Editions, or can find pictures of them on-line.

The information for cover colours on page 12 of BS 7671:2018+A2:2022 only starts at 15th Edition, but it doesn't mean coloured covers were not used earlier ... coloured covers were in fact used from the 8th Edition onwards.

Will BS7671 Amendment 4 address if a domestic dwelling smoke alarm IC (Inter Connect) conductor needs to be colour/identified and which colour should be used?

Reasoning is that BROWN is for 230v nominal AC LIVE and as most/some people know the IC (Inter Connect) is 9V to 12V DC (Direct Current) during alarm operation or heartbeats. Thus maybe the colour for the IC should be RED. That being said that would be under normal operating conditions. Under fault conditions it is POSSIBLE that the IC may become live at 230V AC.

As a side note. In the UK, standard DC cable colour codes are as follows: Red is typically used for the positive (+) wire, and Black for the negative (-) wire thus RED for the IC makes sense to me.

If you identify it as RED and it should be identified/labelled as something in my opinion then at the CU (Consumer Unit) put a note to say RED at smoke/heat alarms is the IC. (Helps the next person)

Caveat time

What if we have old cable in place, Red, yellow, blue? We would now have 2 reds.

What if we have old cable in place, Red, Black, Green/Yellow or bare? We would now have 2 reds.

Sergio Fernandez said:

Will BS7671 Amendment 4 address if a domestic dwelling smoke alarm IC (Inter Connect) conductor needs to be colour/identified and which colour should be used?

Why would it? It's a conductor of a system for which BS 7671 refers out to BS 5839 series in a number of places, including 110.1.3 (v). For example, BS 7671 tells you the identification for PE and FE conductors ... but it won't tell you whether the fire alarm loop earth is PE or FE: that's addressed by BS 5839-1:2025, see Clause 28.2. Similarly, BS 5839-6 already contains a provision that could be tightened up.

In a similar manner, BS 7671 won't tell you which pin is connected to which core in an RJ45 plug or socket-outlet, or that different colours to Table 51 might be used in Machinery to BS EN 60204-1.

Sergio Fernandez said:

Reasoning is that BROWN is for 230v nominal AC LIVE and as most/some people know the IC (Inter Connect) is 9V to 12V DC (Direct Current) during alarm operation or heartbeats. Thus maybe the colour for the IC should be RED. That being said that would be under normal operating conditions. Under fault conditions it is POSSIBLE that the IC may become live at 230V AC.

BUt it's a control/monitoring link (regardless of it being ELV, FELV or LV? BS 7671 permits a number of options at the bottom of Table 51. However, as above, you are referred to in Regulation 110.1.3 to another series of standards to decide what the function is and what the colour identification should be. See below - this is already covered in BS 5839-6.

Sergio Fernandez said:

As a side note. In the UK, standard DC cable colour codes are as follows: Red is typically used for the positive (+) wire, and Black for the negative (-) wire thus RED for the IC makes sense to me.

No, for a DC power circuit, they are Red for L+, White for L-, and this has been printed as such in Table 51 since BS 7671:2018+A2:2022. 

For AC or DC controls, see the bottom of Table 51 (BS 5839-6 already implies this by saying not the same colour as power conductors, see below)

Sergio Fernandez said:

Caveat time

What if we have old cable in place, Red, yellow, blue? We would now have 2 reds.

What if we have old cable in place, Red, Black, Green/Yellow or bare? We would now have 2 reds.

This advice should be provided in BS 5839-6, which specifies the interlink.

BS 5839-6 already makes the following provision (my highlight):

16.4 Recommendations for wiring in Grade D systems
The following recommendations should be met.

a) Cables used for the mains supply to smoke alarms and any heat alarms, and any interconnecting wiring between all smoke/heat alarms, should be suitable for domestic mains wiring.
b) Conductors used for interconnection of smoke/heat alarms should be readily distinguishable from those supplying power (e.g. by colour coding).
c) Wiring systems of any circuits in Grade D systems should conform to the general requirements of BS 7671.

Will BS7671 Amendment 4 address if a domestic dwelling smoke alarm IC (Inter Connect) conductor needs to be colour/identified and which colour should be used?

I thought it already did ... as it's a control line, bottom bit of table 51 applies - so you can choose what you like from Black, Brown, Red, Orange, Yellow, Green, Violet, Grey, White, Pink or Turquoise. I usually find it it convenient to reserve brown/blue for the main L & N - so whatever's left in the 3-core cable can usually be left unsleeved as a control wire.

e.g. Brown/Black/Grey - brown is L, Grey is oversleeved blue as N, so Black is IC. For older installation, Red would be L, blue oversleeved black would be N (by the old convention) so yellow is IC.

   - Andy.

AJJewsbury said:

I thought it already did ... as it's a control line, bottom bit of table 51 applies - so you can choose what you like from Black, Brown, Red, Orange, Yellow, Green, Violet, Grey, White, Pink or Turquoise.

Not quite ... with Clause 16.4 of BS 5839-6, this rules out the use of colours supplying power.

The only argument is whether you take that to be 'colours supplying power' in the entire electrical installation, (which could be BN, BK, GY, BU, RD and WH) or just in the fire alarm installation (that is typically BN and BU in installations with Grade D systems with interlink).

AJJewsbury said:

e.g. Brown/Black/Grey - brown is L, Grey is oversleeved blue as N, so Black is IC

Agreed, save that since neutral used to be black, I might over-sleeve that in blue.

That assumes that a cable can be drawn in from a common point to each alarm. If not, the nearest ceiling mounted luminaire will do and the alarms can be connected by magic (i.e. wirelessly).

If a room has no ceiling mounted luminaire, it becomes more problematic.

Chris Pearson said:

Agreed, save that since neutral used to be black, I might over-sleeve that in blue.

And you might interpret the requirement of BS 5839-6 in a different way, as my previous post, ruling out BN, BK, GY, BU, RD, WH for all installations and additionally YE for installations with "mixed" colours. Assuming we don't want to use GN (to avoid confusion with protective conductor), and PK also being out because it's FE, this then leaves: VT, OG, TQ to choose from.

So, at the next iteration of BS 5839-6, a choice from those three colours, Violet (VT), Orange (OG) or Turquoise (TQ) can be made in what is currently Clause 16.4, and we have a standard approach. Easy.

gkenyon said:

So, at the next iteration of BS 5839-6, a choice from those three colours, Violet (VT), Orange (OG) or Turquoise (TQ) can be made in what is currently Clause 16.4, and we have a standard approach. Easy.

Could that also be added to the following?

OG (On Site Guide)

GN3 (Guidance Note 3: Inspection & Testing)

GN4 (Guidance Note 4: Protection Against Fire)

Will the FIA (Fire Industry Association) be made aware of this recommendation?

Sergio Fernandez said:

gkenyon said:

So, at the next iteration of BS 5839-6, a choice from those three colours, Violet (VT), Orange (OG) or Turquoise (TQ) can be made in what is currently Clause 16.4, and we have a standard approach. Easy.

Could that also be added to the following?

OG (On Site Guide)

GN3 (Guidance Note 3: Inspection & Testing)

GN4 (Guidance Note 4: Protection Against Fire)

Probably not in advance of BS 5839-6 including the provision.

In any case, wouldn't the IET Electrician's Guide to Fire Detection and Fire Alarm Systems be more appropriate? I don't think that OSG, GN3 and GN4 go "inside" fire detection and fire alarm systems to that extent?

Sergio Fernandez said:

Will the FIA (Fire Industry Association) be made aware of this recommendation?

I believe that FIA have representation to the relevant standards committees. Also, consider that public consultation is necessary for British Standard, hence, my recommendation for it to go in BS 5839-6.

A technical committee is usually assembled to consider the IET Electrician's Guide to Fire Detection and Fire Alarm Systems, and I think this also goes out for public consultation if memory serves correctly.

gkenyon said:

Probably not in advance of BS 5839-6 including the provision.

Ok so BS 5839-6 is the start of the journey and you are on point with  IET Electrician's Guide to Fire Detection and Fire Alarm Systems, being included

I assume the  IET Electrician's Guide to Fire Detection and Fire Alarm Systems, is due for a new revision at some point as the 3rd Edition was released in 2021

gkenyon said:

Probably not in advance of BS 5839-6 including the provision.

Ok so BS 5839-6 is the start of the journey and you are on point with  IET Electrician's Guide to Fire Detection and Fire Alarm Systems, being included

I assume the  IET Electrician's Guide to Fire Detection and Fire Alarm Systems, is due for a new revision at some point as the 3rd Edition was released in 2021

Sergio Fernandez said:

I assume the  IET Electrician's Guide to Fire Detection and Fire Alarm Systems, is due for a new revision at some point as the 3rd Edition was released in 2021

Probably, yes, especially as BS 5839-1:2025 is now available.

Sergio Fernandez said:

BS 5839-6 is the start of the journey

I believe so.

Anyone can make a suggestion to include a change in a standard ... the relevant committee can be contacted using the "Message committee" button on their page on the standards development web-site. For BS 5839-6, it's this one: https://standardsdevelopment.bsigroup.com/committees/50002208

BSI advise anyone making suggestions to specifically state the change they would like to see in the standard (what you'd like the words to be changed to). This is also recommended when commenting on drafts for public comment .. see https://standardsdevelopment.bsigroup.com/Home/About