Four things to consider when replacing a consumer unit 

Homeowners change consumer units for lots of reasons: persistent nuisance tripping, a major refurb or rewire, space for EV and heat-pump circuits, or simply because the existing board is outdated. Whatever the trigger, a safe and tidy changeover relies on disciplined surveying, clear design choices, and clean documentation. If you are new to the craft, brush up on core electrical installation principles first, then read on. 

1) Start with facts: survey, test, and agree the scope 

A consumer unit swap is not just a box change. You are taking responsibility for the downstream installation, so establish a baseline before quoting or isolating. 

On site, record: 

• S upply characteristics, Ze/PSCC/PEFC, earthing type, main bonding sizes and routes. 

• Condition of meter tails, service head position, and any DNO notices. 

• Existing circuit schedule (if any), visible damage, signs of thermal stress, borrowed neutrals. 

• Client expectations: spare ways, EV, PV, battery, induction hobs, electric showers, timers, smart controls. 

Testing and paperwork: 

• Carry out an EICR or, at minimum, targeted pre-work tests to reveal faults that will prevent reconnection (ring continuity, insulation resistance, CPC continuity, polarity). 

• Agree in writing how pre-existing faults and remedials will be handled. Unexpected repairs are the number one cause of over-runs and disputes. 

• Confirm outage windows, access, and reinstatement of critical loads (fridges, servers, medical equipment). 

2) Design for the future, not just today 

Few clients regret spare capacity. Most regret the lack of it. 

Allow for growth: 

• Choose a board with spare ways and a busbar that supports later expansion. 

• Consider load management for EV and heat-pump additions. 

• Provide dedicated ways for future TT supplies or outbuildings where discrimination is needed. 

Select appropriate protection: 

• SPD where required or where sensitive electronics are present. 

• AFDDs where specified or risk-assessed appropriate (HMOs, sleeping risks, or client preference). 

• RCD type matched to likely loads: Type A for most modern appliances, Type F/B where manufacturers specify. 

Layout matters: 

• Group high-leakage circuits sensibly to reduce cumulative RCD trips. 

• Label clearly, leave a legible schedule, and keep conductor dressing serviceable for the next inspection. 

3) Prioritise critical circuits and separation 

A single earth-leakage fault should not drop smoke alarms or security. 

• Use all-RCBO or high-integrity configurations to keep priority circuits independent. 

• Separate kitchen and freezer circuits from general sockets where budgets allow. 

• If using dual-RCD boards, plan the split to keep essential services on different sides and balance expected leakage. 

Clear separation reduces nuisance trips and client call-backs, especially in houses full of switching power supplies and EV chargers. 

4) Choose the right enclosure and components 

A neat, compliant install starts with the right kit. 

Enclosure and hardware: 

• Non-combustible metal enclosure sized for working space, cable entries, and future ways. 

• Sturdy fixing to a sound backboard or surface; protect cables where they pass sharp edges. 

• Tails sized and routed correctly, with proper glands/ferrules; main switch and devices torque-set to manufacturer specs. 

• Suitable IP rating if sited in dusty, damp or external locations; avoid bathrooms and lofts where practical. 

Board type: 

• Fully loaded dual-RCD: budget-friendly, acceptable for small/simple installs. 

• High-integrity: mix of RCBOs and RCD ways for sensible separation at modest extra cost. 

• All-RCBO: maximum selectivity and easier fault isolation; usually the best lifecycle value. 

Safety, compliance and paperwork checklist 

• Work is notifiable (England & Wales). Either notify building control in advance or be registered with a Competent Person Scheme and issue the Building Regulations compliance certificate after completion. 

• Issue an Electrical Installation Certificate with schedules of inspections and test results. 

• Fit labels for isolation points, SPD/AFDD presence, and any special instructions; update or create a circuit schedule. 

• Verify main bonding to water/gas, check meter-tail condition, and confirm service head seals are intact (liaise with DNO as required). 

• Leave the area clean, demonstrate RCD/RCBO tests to the client, and explain what to do after a trip. 

Typical process, step by step 

1. Survey & quote: record supply, bonding, circuits, and client needs; flag likely remedials. 
   
   
2. Prep: pre-order the correct board, devices, blanks, glands, tail kits, labels; plan containment and cable routing. 
   
   
3. Safe isolation: prove your tester, isolate, lock off, and tag. 
   
   
4. Strip out & mount: remove the old unit, prep backboard, gland entries, mount the new enclosure level. 
   
   
5. Terminate & dress: fit main switch, SPD/AFDDs/RCBOs, dress conductors with service loops. 
   
   
6. Test: continuity, insulation resistance, polarity, Zs, RCD/RCBO performance; record results. 
   
   
7. Energise & verify: functional checks, label, complete EIC and notify building control where applicable. 
   
   
8. Handover: demonstrate operation, leave documentation, and schedule the first periodic inspection. 

Pricing and expectation management 

Be t ransparent about what the “board change” includes—and what it does not. 

• Price remedials separately once uncovered by testing (ring breaks, low IR, missing CPCs). 

• Itemise upgrades (SPD, AFDDs, extra ways) so clients can choose with full information. 

• For older properties, include a contingency line; explain why it protects both parties. 

• Put all assumptions in writing: access, working hours, making good, client-supplied accessories. 

Clear paperwork prevents disputes and protects your time. 

New to consumer unit work? Build skills the smart way 

If you are an electrician in training, start by mastering safe isolation, test sequences, and documentation on rigs before you tackle live board changes. Midlands-based and want hands-on support with real boards and small cohorts? Check intakes at Electrician Courses Stoke-on-Trent. 

To progress from supervised tasks to signing off your own work, complete your portfolio and end assessment via the nvq level 3 electrical fast track route. As your confidence grows, revisit design choices, practice tidy conductor dressing, and keep your test documentation immaculate. That is what separates a simple swap from a professional upgrade—and it is what clients remember. 

Finally, keep your fundamentals sharp. Regular refreshers in core e lectrical installation principles will pay you back every time you open a board cover.