Should I get an EICR before deciding on a rewire?

Yes, in almost every case. An EICR is the diagnostic step: it tests insulation resistance, earth continuity and polarity across every circuit and tells you objectively whether the cabling is sound. Deciding on a rewire without one is guesswork.

Can a consumer unit upgrade fix an unsatisfactory EICR?

It can, where the coded observations relate to the protective devices — no RCD protection, a combustible enclosure, no main protective bonding. It cannot fix observations relating to the cabling itself, such as low insulation resistance or damaged conductors.

Is a partial rewire a real option?

Yes. Where testing shows, for example, that the lighting circuits have deteriorated but the socket circuits are sound, replacing only the affected circuits is legitimate and properly certified. The certificate records exactly which parts of the installation are new.

Which gives the best return if I'm selling?

A satisfactory EICR is usually the best value. It costs a fraction of the other two and it removes the uncertainty a buyer would otherwise price into their offer. Only carry out remedial or replacement work that the report actually identifies.

Comparison

EICR vs rewire vs consumer unit upgrade: which do you need?

By Steve Green · Updated 6 August 2026 · 7 min read

Start with an EICR — it is the diagnosis, not the cure. A consumer unit upgrade fixes protection problems: no RCD, a combustible enclosure, inadequate bonding. A rewire replaces the cabling and is only necessary when testing shows the conductors themselves have deteriorated. Doing them in the wrong order is how people end up paying twice.

The three options at a glance

	EICR	Consumer unit upgrade	Full rewire
What it is	Inspection & test report	New protective devices	All cabling replaced
Fixes anything?	No — diagnoses only	Protection faults	Cable deterioration
Time on site	2–4 hours	4–6 hours	5–15 working days
Disruption	Power off in stages	Power off most of a day	Significant — chasing, dust
Redecoration needed	No	No	Yes
Certificate issued	Condition Report	EIC / Minor Works	EIC + Part P notification
Typical lifespan gained	n/a (5–10 yr validity)	20–25 years	25–30 years

Choose an EICR if…

You do not know the age or condition of the installation
You are buying, selling or letting — see EICR when selling
A survey has recommended further electrical investigation
You have been quoted for a rewire and want an independent second opinion

Book EICR testing first in every one of these cases. It is the cheapest step and it prevents the other two being sold to you unnecessarily.

Choose a consumer unit upgrade if…

You have rewireable fuses or no RCD protection — see fuse board vs consumer unit
The EICR codes relate to the board, bonding or enclosure rather than the circuits
Insulation resistance across circuits tests sound
You need capacity for an EV charger, shower or outbuilding

Get the sizing right first time — what size consumer unit you need.

Choose a full or partial rewire if…

Insulation resistance is low across multiple circuits
Rubber, lead or fabric-sheathed cabling is present
There is no circuit protective conductor (earth) on lighting circuits
Multiple C1 or C2 codes relate to the wiring itself
You are already stripping the property back for a renovation

The 10 signs cover the symptoms, and how long a rewire takes covers the practicalities.

The order that saves money

EICR — establish the facts and get them in writing.
Address C1 items immediately — these are live dangers, regardless of any wider plan.
Decide between board upgrade and rewire based on the insulation resistance results, not the age of the house.
If rewiring, do the board as part of it — never pay for it twice.
Retest and certify, and keep the paperwork with your property documents.

A note on quotes

Be cautious of any quote for a rewire or a new board issued without testing the existing installation first. A genuine recommendation cites the measured results — insulation resistance in megohms, earth fault loop impedance, RCD trip times. If a quote does not reference test results, ask for them before committing.

Frequently asked

Should I get an EICR before deciding on a rewire?: Yes, in almost every case. An EICR is the diagnostic step: it tests insulation resistance, earth continuity and polarity across every circuit and tells you objectively whether the cabling is sound. Deciding on a rewire without one is guesswork.
Can a consumer unit upgrade fix an unsatisfactory EICR?: It can, where the coded observations relate to the protective devices — no RCD protection, a combustible enclosure, no main protective bonding. It cannot fix observations relating to the cabling itself, such as low insulation resistance or damaged conductors.
Is a partial rewire a real option?: Yes. Where testing shows, for example, that the lighting circuits have deteriorated but the socket circuits are sound, replacing only the affected circuits is legitimate and properly certified. The certificate records exactly which parts of the installation are new.
Which gives the best return if I'm selling?: A satisfactory EICR is usually the best value. It costs a fraction of the other two and it removes the uncertainty a buyer would otherwise price into their offer. Only carry out remedial or replacement work that the report actually identifies.

Need a straight answer about your own property?

Call 0203 576 6961 — answered by a real person, available 24/7 — or request a free written quote.