Free Consumer Unit Replacement Cost Calculator
Estimate the cost of replacing your fuse box or consumer unit. Compare RCD and RCBO options based on your number of circuits and location.
This consumer unit cost calculator helps homeowners estimate the cost of upgrading or replacing their fuse box (consumer unit). Enter your current setup, number of circuits, upgrade preference, and postcode to get a price estimate based on real local electrician rates. All consumer unit replacements are notifiable under Part P and require certification.
Results
Fill in the details and select Calculate to see your figures.
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Get a free demoHow to use the Consumer Unit Replacement Cost Calculator
- 1Identify your current consumer unit type. Check if it has rewirable fuses, MCBs with an RCD, or a split-load setup.
- 2Count the number of circuits (fuses or MCBs) in your current unit.
- 3Choose whether you want a dual RCD board (cheaper, standard protection) or a full RCBO board (each circuit individually protected).
- 4Enter your postcode. We use real local electrician day rates to adjust the estimate for your area.
- 5The estimate includes Part P certification when done by a registered electrician.
How to work it out yourself
A consumer unit replacement is a regional price estimate, not a fixed formula. It is essentially a base board-and-labour cost plus a small amount per extra circuit, adjusted for how much extra work the old setup needs and for local rates.
- Dual RCD board, national rates: base £400–£550.
- 10 circuits = 2 above the 8-circuit baseline, at ~£15 each = +£30.
- Replacing an old fuse box (likely earthing/bonding work) adds ~£120 → roughly £550–£700 before any local uplift.
- A full RCBO board costs more (base £600–£800, ~£35 per extra circuit) because each circuit gets its own protective device.
This is a cost breakdown, not an engineering formula. The figures are calibrated to real UK electrician pricing. A replacement is notifiable under Part P; the certificate is included when a registered electrician does the work, but faults found during testing (earthing, bonding, damaged cables) can add cost.
Typical UK benchmarks
| UK Average Consumer Unit Replacement (10-way RCBO) | £350-£800, averaging £485 for a standard 10-way RCBO board (Checkatrade Consumer Unit Replacement Cost guide, 2026) |
| Large Property / 12+ Circuits | Up to around £800 for a large detached property or 12+ circuits (Checkatrade Consumer Unit Replacement Cost guide, 2026) |
| Part P Certification | Included in the price when a registered electrician (NICEIC/NAPIT) self-certifies the work (Approved Document P; NICEIC) |
Disclaimer
This tool gives an estimate for general guidance only, based on typical UK figures and the details you enter. It is not a formal quote, survey, or professional advice. Always confirm with a qualified tradesperson before relying on any figure, as regional prices, site conditions, and current standards vary.
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Get a free demoFrequently asked questions
How much does it cost to replace a consumer unit?
According to Checkatrade's 2026 cost guide, a consumer unit replacement typically costs £350-£800, averaging around £485 for a standard 10-way RCBO board, rising toward £800 for a large property with 12+ circuits. London and the South East prices generally run higher. The price includes the consumer unit, labour, testing, and Part P certification. Old fuse boxes with rewirable fuses may cost more to replace if the existing wiring needs attention.
What is the difference between RCD and RCBO?
A dual RCD board splits your circuits into two groups, each protected by an RCD. If one RCD trips, you lose half your circuits. An RCBO board gives each circuit its own individual protection. If one trips, only that circuit is affected. RCBOs cost more but offer better protection and less inconvenience.
Do I need a Part P certificate?
Yes. Replacing a consumer unit is notifiable work under Part P of the Building Regulations. If a registered electrician (NICEIC, NAPIT, etc.) does the work, they self-certify and the certificate is included. If an unregistered electrician does the work, you must apply to Building Control separately, which costs £200-£400 extra.
How long does a consumer unit replacement take?
A straightforward consumer unit swap typically takes 4-6 hours (half a day to a full day). If additional work is needed: such as upgrading earthing, replacing the meter tails, or addressing issues found during testing. It may take a full day or more.
Should I upgrade to an RCBO board?
If budget allows, yes. The extra cost (typically £200-£400 more) is worth it for the convenience and safety. With a dual RCD board, a fault on one circuit can trip the RCD and cut power to several other circuits: including freezers, security systems, and medical equipment. RCBOs prevent this.
