Consumer Unit Regulation - Free Complete Guide of the 18th Edition (2023)

Join our new Facebook group where you can continue the discussion and learn in a non-judgmental environment! CLICK HERE - Electric Assistance Facebook Group

There has been a lot of confusion regarding changes in wiring regulations and how they affect consumer unit regulations.

Since the introduction of the 18th edition, some new regulations have been added to certain regulations that affect the installation of consumer units. AMD2 also brought a number of different requirements from the original 18th edition.

AMD2 UPDATES on consumer unit regulations are highlighted in RED

In this blog post, we'll take a look at those regulations and see exactly what they mean for you, whether you're installing a new consumer unit or purchasing an EICR.

I'll try to keep each section short and sweet, but there's too much to fit here, making the entire post quite long.

It can be helpful to use the content section that breaks each part into manageable chunks so that you can find out exactly which consumer unit regulations apply to the installation you are completing/testing.

Construction of consumer units

Since the introduction of AMD3 17th Edition in 2015, consumer units in residential buildings must be made of a "non-combustible" material.

This usually means that all domestic plumbing must now have a metal consumer unit installed, unless the consumer unit is installed in a non-combustible enclosure.

While it is not mandatory to upgrade older facilities just because they have a plastic charge unit, all new facilities are now required to meet this standard.

EICRs in older facilities often encounter plastic consuming units. They should only be coded as C3 - RECOMMENDED UPDATE, there is no requirement in BS7671 for 'failure' so please update these older plastic units

The relevant consumer unit specific provision in the 18th edition is 421.1.201

It should be noted that this regulation does not apply to commercial systems where plastic consumers can still be installed.

Also, you can stay in private dependencies, e.g. sheds and garages, still install plastic consumer units, as long as the annex is not connected to the main building.

The reason for updating this regulation in consumer units is due to the number of fires in plastic panels. However, this is not true causation, as the only reasons they would catch fire are an internal error or improper installation.

A fireproof consumer unit ensures that any fire is contained within the enclosure itself and does not spread to surrounding building materials.

Prior to this, installing a metal consumer unit on a TT ground system was always frowned upon due to the risk of powering up the cabinet and not shutting down the main OCPD.

This is a puzzle that needs a completely different guide, and that's exactly what we did! Please verify:Can I install a metallic consumer on a TT grounding system?

Circuit failure - RCD or RCBO?

This is a hotly contested debate among electricians. Dual charge and split RCD cards were popular in earlier versions of the BS7671. While they never really met the circuit-sharing requirements, they were a safe compromise.

It must be recognized, however, particularly as RCBOs are so numerous and relatively inexpensive, that an RCBO board actually complies with consumer unit regulations, particularly the parts of BS7671 relating to splitter circuits to minimize disturbances in the event of a failure.

Not only do RCBOs minimize end-user inconvenience, but they also allow for much faster troubleshooting because it's clear what the circuit is right from the start. Duplicate RCD cards do not allow this, each RCD can cover a wide range of circuits, making troubleshooting difficult.

Maximum leakage current in RCD / RCBO

The 18th edition of BS7671 brought a new consideration for RCD equipped sets, a big change with Reg ????

This stipulates that the maximum leakage current under normal use conditions must not exceed 33% of the rated trip current of the device.

For a normal 30mA RCD, this essentially means that the regular leakage current should not exceed 10mA under normal circumstances.

While that might seem like a lot, a modern home with lots of appliances and appliances can create leakage current in normal use.

In the case of a dual RCD board, where multiple circuits are shared on a single RCD device, this leakage current can easily exceed the 33% allowable for the single RCD unit.

While RCBO boards are still under the same regulation, they are less likely to exceed the 33% limit as they only cover a single circuit.

There may still be cases (especially with IT equipment in offices) where this could be an issue, but this would require the circuit design to take this into account, with a limited number of sockets per circuit or similar.

RCD Type (AC, A or B) - AMD2 UPDATE!

The nature of RCD has been further questioned with the recent introduction of Amendment 2 to the 18th edition of BS7671.

This section of the regulations for consumer units now requires that AC type RCDs can only be used for stationary devices without a DC component.

This is now a requirement to use at least Type A RCDs (and in some cases, particularly in certain types of EV charger installation, Type B RCDs) for sockets and all fixed equipment that may contain a DC component. Now that everything has electronics on board, this covers a wide spectrum.

In the vast majority of cases, this will be the end of the AC RCD type, as manufacturers strive to at least consolidate the A type.

Surge protection devices

Surge protectors have been around for years in special situations where there is a risk of damaging computers or other sensitive hardware.

It is recommended to install them in cases where there were previously certain risks of overvoltages; However, the 18th edition actually expanded its usage significantly.

To determine whether or not a surge protector should be installed, an assessment can be made using a formula specified in the 18th Edition. This deserves a post of its own, so we won't go into too much depth here.

However, suffice it to say that the cost of these devices has dropped significantly, as the demand for them has increased since the release of the 18th edition.

A T2 SPD for most national brands is available for £50 or less at the time of writing (Feb 2022). With that cost, along with the advent of a ton of sensitive equipment like TVs, computers, and digital devices, installation is a breeze.

Our standard practice is now to incorporate them into all consumer unit installations. The costs are offset by improvements in the useful life of sensitive equipment.

Not only surges of atmospheric origin (eg lightning), SPDs can also protect against small surges from constant switching of devices inside the building.

AMD2 UPDATE: Removed Flash Map from Issue 18 of the original Blue Book. This has been replaced with a simpler SPD installation guide. In principle, SPDs are installed when replacing a consumer or in a new installation, unless the customer agrees in writing with the omission.

arc detection devices

As AMD2 Edition 18 was released just a few weeks after I wrote this (Feb 2022), I'll leave this section up for the update, which I will do once AMD2 launches properly and we know how it will affect unit regulations.

Suffice it to say that arc-flash detection devices (AFDDs) have historically been expensive and only recommended for certain areas with a particular risk of arc-flash.

This could become a requirement in a wide range of installations (even normal home installations) after the introduction of AMD2.

Unlike SPDs, which only require a single unit per panel (or at the entrance to the facility), AFDDs are "per circuit" the same as an RCBO.

While the cost of these devices is still quite high, it is likely (as was the case with SPDs) that the cost will come down once they are mass produced.

AMD2 update: Biggest change to consumer propulsion regulations for 2022 affects installation of arc fault detection devices (AFDDs)

We'll cover these in detail shortly, but to recap they are now required for installations in certain defined hazard residential buildings (greater than 6 floors), nursing homes, HMOs, and a small number of other cases for outlets rated below 32A

Recommendations for its use are also provided for other circumstances, but you should approach these on a case-by-case basis.

Labeling of consumer units

There are several consumer unit regulations that apply to labels that must be affixed to the unit itself (or, in some cases, proximity is acceptable, with multiple panels and cabinets).

The most obvious of these are the labels that indicate the purpose of the frame. In a simple home installation, these would be the labels under the MCBs/RCBOs. In commercial cases, this could be labeled for overcurrent protection devices in switchgear, but it could also be labeled on switched fuse units and the like.

Test and test marking

There should be a label showing the date of the last inspection and test performed on the installation. This should also indicate the recommended date of the next inspection and test, depending on the type of installation and how it is used, this could range from 3 months to 10 years.

Especially for owners with the newPRS (Private Rental Sector) Regulations 2020which require national private owners to file a new EICR every 5 years. For owner-occupied residential properties, a 10-year review may be recommended if they are particularly new and have no obvious reason for overuse.

BS7671 Two-color warning sticker

18. AMD2 AWESOME! The old and reliable BS7671 two-tone warning signal is no longer needed!!

If the installation wiring uses the previous colored insulation at any point, ie. H. red and black non-harmonized colors (before 2004), so a label indicating the use of cable colors must be affixed to the consumer unit. for 2 versions of BS7671. .

There is still a significant amount of this cable installed in the UK and it will be good for years to come. Therefore, expect to see these labels on a very high percentage of installs.

However, the latest AMD2 updates have removed the BS7671 requirement for two-color warning labels, as many consumers end up removing them from the front of the consumer unit, especially if the consumer unit is in a room and not under the stairs or in the basement. basement !

RCD test label

If the installation has RCDs affixed in any way, a warning label must be affixed to test them on the consumer unit. For 18th edition (new) installations, this should be tested every 6 months, although the label previously intended testing every 3 months.

If you're checking older installations, the old label is fine without change, because in a bizarre (but understandable) relaxation of all consumer unit regulations, the requirements for checking intervals have actually gotten longer rather than more frequent!

other letters

There are a number of other labeling requirements for use in special circumstances, including but not limited to:

• More than one reference source (IE: Microgeneration)
• Ungrounded circuits (very rare today, but some older installations still don't have CPCs in the lighting circuits)
• Live parts that cannot be isolated with a single device: If a single board is connected to 2 power supplies (for example, dual rate accessory for economy customers7 with a single dual rate board), a warning label must be attached

As innocuous as it may sound, the markup on the BS7671 is actually deeper than you might think, depending on your installation and specific circumstances. Therefore, it would be too exhaustive to cover them all in our consumer unit regulations guide! We'll be writing a complete BS7671 markup guide shortly and linking to it from here.

AMD2 Update: All requirements for the above mentioned warnings in the other markup header still exist in AMD2:2022

Related