Your Complete Guide
to Consumer Units
Plain English homeowner reference covering everything from board basics through to BS 7671 wiring regulations. RCDs, RCBOs, AFDDs, costs, landlord rules and when to upgrade. Written for homeowners across Milton Keynes.
This guide covers everything UK homeowners need to know about consumer units. From the basics of what sits inside the metal box on your wall through to the regulation that mandates metal enclosures, the difference between RCDs and RCBOs and AFDDs, what a landlord legally needs and when an upgrade is actually necessary. Twenty five plain English guides organised into six topic clusters. Use the navigation below to jump to what you need.
The numbers behind
every UK consumer unit
These figures shape every decision homeowners make about their consumer unit. Each is grounded in BS 7671 and Part P of the Building Regulations.
In This Knowledge Base
Twenty five homeowner explainers covering basics, protection devices, regulations, costs and landlord rules. Updated against the latest BS 7671 amendments.
Metal Enclosure Rule
Since the third amendment to BS 7671, all new domestic consumer units must have a non-combustible metal enclosure. Plastic boards no longer comply on new installs.
Landlord EICR Cycle
Since June 2020, every English rental property must hold a satisfactory EICR renewed every five years. The consumer unit is the most common failure point.
Typical Lifespan
A modern metal RCBO board fitted to BS 7671 typically serves a property reliably for 25 to 30 years before regulation-driven replacement is sensible.
Six clusters,
twenty five guides
Consumer Unit Basics
Five plain English explainers covering what a consumer unit is, the components inside it and how each part contributes to keeping your home safe.
What a consumer unit actually is
A complete homeowner explainer on what is a consumer unit covering the metal box that controls every circuit in your home, what sits inside it and how it differs from older fuse boxes and distribution boards.
Read guideThe main switch explained
Your guide to what is a main switch in a consumer unit covering the double-pole isolator at one end of the board, what it does, when to use it and why it is the first thing to reach for in an emergency.
Read guideMain earthing terminal
Read our explainer on what is a main earthing terminal to understand the single point where your supply earth lands, why it matters and how every protective conductor in your home traces back to it.
Read guideBonding in electrical systems
Our guide to what is bonding in electrical systems covers main protective bonding to gas and water, supplementary bonding and why these connections are critical for shock protection.
Read guideFuse vs circuit breaker
Read about what is a fuse vs circuit breaker to understand the move from rewireable fuse wire to modern miniature circuit breakers and why the change happened.
Read guideConsumer Unit Upgrades
in Milton Keynes
C-Lec Electrical fits NAPIT certified consumer units across Milton Keynes. 18th Edition metal boards, surge protection and full Building Control notification handled in one day. Fixed pricing from £650 ex VAT.
Protection Devices Explained
Eight guides covering the protective devices inside your consumer unit. RCDs, RCBOs, AFDDs and surge protection, with how the different board configurations stack up.
Dual RCD boards
Read our guide on What is a Dual RCD Board to understand the split-load design with two main RCDs covering banks of circuits, what it protects against and its main weakness.
Read guideRCBO boards
Our explainer on What is an RCBO Board covers the modern recommended standard where every circuit gets its own combined RCD and MCB protection in a single device.
Read guideAFDD boards
Read our guide on What is an AFDD Board to understand arc fault detection devices, what they protect against and when BS 7671 recommends them.
Read guideSurge protection devices
Our explainer on what is surge protection (SPD) covers transient overvoltage protection, why every modern board should have one and what it shields against.
Read guideRCBO vs dual RCD board
Read our comparison on RCBO vs dual RCD board to see exactly how each design handles a fault and why most new installs now use full RCBO protection.
Read guideAFDD vs RCD
Our comparison on AFDD vs RCD covers what each device detects, where they overlap and where AFDDs catch faults that traditional RCDs cannot.
Read guideSplit load vs high integrity
Read our explainer on what is a split load board vs high integrity board to understand the two main design philosophies and when each is appropriate.
Read guideAre RCDs legally required?
Our guide on are RCDs legally required in UK homes covers the BS 7671 requirements, when an RCD becomes mandatory and what an EICR will flag if missing.
Read guideIf you have already worked out that your existing board needs replacing, you can skip the research and get straight to a quote. Our consumer unit upgrades Milton Keynes service handles every install end to end. Free site visit, NAPIT certified install, EIC and Building Control notification on completion.
Plastic vs Metal Boards
Three guides covering the metal enclosure requirement that came in with the third amendment to BS 7671. What it means for new installs and existing plastic boards.
Plastic vs metal consumer units
Read our breakdown on plastic vs metal consumer units covering the safety differences, the regulation change and what it means for your existing plastic board.
Read guideIs metal required by law?
Our guide on is a metal consumer unit required by law covers exactly what BS 7671 requires, when the rule applies and when an existing plastic board can stay.
Read guidePlastic boards and EICR
Read our guide on does a plastic consumer unit fail an EICR to find out exactly when a plastic board is flagged, what code it gets and what counts as a fail.
Read guideWhen to Upgrade
Three guides covering the most common questions homeowners ask before booking an upgrade. Whether yours actually needs replacing, the impact on a property sale and a full pre-install checklist.
Do I need to upgrade?
Read our self-assessment guide on do I need to upgrade my consumer unit covering the warning signs, the regulation triggers and when an upgrade is genuinely necessary versus optional.
Read guideSelling with an old board
Our guide on can I sell my house with an old consumer unit covers what surveyors flag, mortgage implications and whether to upgrade before listing or negotiate the cost in.
Read guideUpgrade checklist for homeowners
Read our consumer unit upgrade checklist for homeowners covering everything to check, ask and prepare before booking the work in. Pricing questions, timing and paperwork.
Read guideCosts & Installation
Four guides covering the cost ranges, the install process from quote to certificate, garage applications and the most common install mistakes to watch for.
How much to change a board
Our pricing guide on how much to change a consumer unit covers typical UK cost bands, what affects the price and what should always be included in a quote.
Read guideHow to wire a consumer unit
Read our walkthrough on how to wire a consumer unit covering the four stages a registered electrician follows on the day. Note this is for understanding only, not a DIY guide.
Read guideWiring a garage board
Our guide on how to wire a consumer unit in a garage covers the additional considerations for outbuildings, sub-board configurations and the cabling requirements.
Read guideCommon install mistakes
Read our list of common consumer unit installation mistakes covering the issues we see when remediating other engineers' work and how to spot them on your own board.
Read guideRegulations & Compliance
Two regulation-focused guides covering the BS 7671 wiring regulations and the specific landlord rules for rental properties under the 2020 Electrical Safety Standards.
Latest wiring regulations
Read our breakdown of the latest wiring regulations for consumer units (BS 7671 explained) covering the 18th Edition requirements and the amendments that affect new installs.
Read guideLandlord requirements
Our guide on landlord requirements for consumer units in the UK covers the 2020 Electrical Safety Standards Regulations, the EICR cycle and the consequences of non-compliance.
Read guideCommon questions answered fast
What is the difference between a fuse box and a consumer unit?
How long does a consumer unit last?
Is my plastic consumer unit illegal?
Can I install a consumer unit myself?
What is the difference between an RCD and an RCBO?
Do I need an AFDD board?
Let C-Lec Handle
Your Consumer Unit
Once you have read enough, the next step is straightforward. Free site visit, fixed pricing from £650 ex VAT, NAPIT certified install and full Building Control notification. We cover Milton Keynes and the surrounding area.