Testing & Commissioning
Electrical testing and commissioningin Stevenage and Hertfordshire
New and existing installations tested properly against BS 7671, with results you can rely on: before anything is signed off as safe to use.
NICEIC Approved Contractor · Rated 4.95 out of 5 on TrustATrader
NICEIC
Approved Contractor
20 yrs
experience
4.95/5
TrustATrader rating
£10m
public liability cover
24 hrs
phone line answered
The service
Electrical testing done to standard
Testing and commissioning is the final, essential stage of any electrical installation: new or altered. It confirms that the work carried out is actually safe and compliant with BS 7671, the UK wiring regulations, before it's put into everyday use.
Linehan Electrical is a NICEIC Approved Contractor based in Stevenage, covering Hertfordshire, Bedfordshire, Cambridgeshire and London. We carry out testing on our own installations as standard, and we're also called in to test and commission work carried out by others, including EICRs on existing properties.
We've tested everything from a single rewired circuit in a flat to full distribution boards on larger commercial and industrial sites, so the scope of testing we carry out flexes to match the job: a quick circuit test is a different undertaking to commissioning a new LV panel board.
Every quote is free. Small jobs can often be quoted from photos or a description, while larger testing jobs, particularly commercial commissioning, need a site visit to scope properly.
If it's left
Why testing can't be skipped
Installing wiring and equipment correctly is only half the job: testing is what actually proves it's safe. Skipping it, or doing it badly, leaves real risk hidden behind a finished-looking job.
Untested new work
Visually a new circuit can look fine while still having a wiring fault, reversed polarity or a failed earth connection underneath.
RCDs that don't trip correctly
An RCD that looks installed but hasn't been tested may not actually disconnect within the required time in a real fault.
Incorrect test results ignored
Readings outside expected parameters point to a real problem | ignoring an odd result rather than investigating it defeats the purpose of testing.
Ageing installations with no record
Properties with no history of testing carry unknown risk | faults can sit undetected for years.
Commissioning rushed on commercial jobs
On larger installations, rushing commissioning to meet a deadline risks missing faults across multiple interconnected circuits.
Uncertified work on resale or letting
Properties without test certificates or reports can run into problems at sale, remortgage or letting stage.
Common mistakes we see
- ×Treating testing as a formality rather than a genuine safety check
- ×Using uncalibrated or inappropriate test equipment
- ×Skipping testing on 'minor' alterations because they look straightforward
- ×Not keeping test certificates and EICRs on file
- ×Assuming an installation is safe because it was done by a previous contractor
- ×Leaving commercial commissioning until the last possible day before opening
How we work
How we approach testing and commissioning
- 01
Scope the job
We confirm what needs testing | a new circuit, a full installation, or an existing property needing an EICR | and give a free quote.
- 02
Visual inspection
Before live testing, we visually check wiring, connections, labelling and equipment for anything obviously wrong.
- 03
Dead and live testing
Using calibrated equipment, we test insulation resistance, earth continuity, polarity, loop impedance and RCD operation in line with BS 7671.
- 04
Review results
Readings are checked against expected values. Anything outside tolerance is investigated and resolved before sign-off.
- 05
Certification and handover
You receive the relevant certificate or report, explained in plain terms. All our own installation work carries a 12-month workmanship guarantee.
What you get
Why proper testing matters
Confirms real safety
Testing verifies an installation actually meets the required standard, not just that it looks finished.
Straightforward turnaround on most jobs
Standard testing on a single installation or small property is usually completed in one visit.
Documented evidence
Certificates and reports give you a record for insurance, sale, letting or compliance purposes.
Scoped to the job
Pricing reflects the size of the job | from a single circuit to a full commercial commissioning.
Accredited standard
Testing is carried out by a NICEIC Approved Contractor using calibrated equipment.
Peace of mind
Knowing an installation has actually been proven safe, not assumed safe, is worth more than the cost of the test.
In detail
Testing and commissioning in detail
Testing covers a range of certificate types and methods depending on whether you're commissioning new work or checking an existing installation.
Types of testing we carry out
Initial verification testing on new installations and alterations, confirming the work is safe before it's used. Periodic testing on existing installations in the form of an EICR, assessing condition against current standards. Fault-finding related testing, where diagnostic testing identifies the cause of a reported problem.
What's actually measured
Insulation resistance confirms cable insulation hasn't degraded enough to leak current. Earth continuity confirms every circuit has a sound path to earth. Polarity checks live, neutral and earth are correctly connected at every point. Loop impedance confirms protective devices will operate fast enough in a fault. RCD testing confirms residual current devices trip within the required time to protect against shock.
Equipment and methods
We use calibrated multifunction test instruments designed for electrical installation testing, following the sequence and methods set out in BS 7671. Dead testing (with the circuit isolated) is carried out first, followed by live testing once it's confirmed safe to re-energise.
Commissioning larger installations
On commercial and industrial jobs, commissioning can involve multiple distribution boards, three-phase circuits and interconnected plant and equipment. We've tested and commissioned installations up to LV panel board level in warehouse environments, so larger commissioning jobs are scoped and sequenced to suit the site rather than treated like a single domestic circuit.
Domestic vs commercial testing
Domestic testing is usually quicker and more contained: a consumer unit and its circuits, or a single new addition like an extension or extra socket circuit. Commercial testing covers a wider range of equipment, often across multiple floors or units, and may need to be scheduled around business operating hours to avoid disruption.
Related services
Questions
Frequently asked questions
How much does electrical testing cost?
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It depends on the scope: a single circuit test costs less than a full EICR, and commercial commissioning is priced per job. EICRs are typically £220 for a 3-bed property with one fuseboard. We always give a free quote first.
How long does testing take?
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A single circuit or small domestic job is usually tested in one visit. Larger properties or commercial commissioning takes longer depending on the number of circuits.
Do you test work carried out by other contractors?
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Yes, we carry out independent testing, including EICRs, on existing installations regardless of who originally installed them.
What certificate will I get?
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This depends on the work: new installations get an Electrical Installation Certificate, existing properties get an EICR. We'll confirm which applies before starting.
Is your testing guaranteed?
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Our own installation workmanship carries a 12-month guarantee. Testing and reporting on existing installations reflects the condition found at the time of inspection.
Can you test out of hours or on commercial premises during downtime?
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Our phone line is answered 24 hours a day so you can discuss scheduling, though we don't promise a fixed attendance time.
Do you commission large commercial installations?
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Yes, we've commissioned work up to LV panel board level on commercial and industrial sites, as well as smaller domestic jobs.
What's the difference between testing and an EICR?
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Testing is the general activity of checking an installation's safety. An EICR is the specific formal report produced from periodic testing of an existing installation.
Do you cover testing across Hertfordshire?
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Yes, we cover Stevenage and the wider Hertfordshire area, plus Bedfordshire, Cambridgeshire and London.
Are you accredited to issue test certificates?
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Yes, we're a NICEIC Approved Contractor, covered by £10m public and £10m employers' liability insurance.
Get your installation tested and certified
Whether it's a single circuit or a full commercial commissioning, tell us what you need and we'll give you a free quote.
- NICEIC Approved Contractor
- 12-month workmanship guarantee
- 4.95 on TrustATrader