Company lists · Data refreshed September 2026
Top 25 Insulation resistance testing services based in the United Kingdom
RevenueBase identified 116 insulation resistance testing services headquartered in the United Kingdom as of September 2026 and tracks 625 professional contacts across them, including 226 with verified work emails. London is the largest hub.
This list covers insulation resistance testing services headquartered in the United Kingdom, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 20, 2026.
Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.
The 25 largest insulation resistance testing services based in the United Kingdom
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 83 contacts → | ||||
Partial evidence “With over 75 years’ experience at the cutting edge of electrical safety testing, our expertise and innovations have produced a number of world firsts.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 2 | 51 contacts → | ||||
Partial evidence “Monitra (formerly HVPD) are experts in the field of Partial Discharge (PD) testing and monitoring of Medium Voltage and High Voltage electrical equipment, which can be performed…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 3 | 42 contacts → | ||||
Indirect evidence “Calbarrie Compliance Services Ltd (Calbarrie) is the UK’s market leader in electrical compliance services and has been trading within the Health & Safety and Compliance sectors…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 4 | 36 contacts → | ||||
Partial evidence “COMPANY OVERVIEW Based near Southampton, Intersafe are compliance specialists providing a range of electrical testing services for large, commercial sites.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 5 | 32 contacts → | ||||
Indirect evidence “For the last 25 years, Group Management Electrical Surveys have been providing Electrical Inspection, Test and Documentation services to many of the UK's leading companies.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 6 | 32 contacts → | ||||
Partial evidence “With over 95 years of experience, Martindale Electric is one of the most trusted brands in electrical safety testing.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 7 | 21 contacts → | ||||
Partial evidence “At Novus Compliance Services Ltd we specialise in Electrical Testing and Inspection, Maintenance, Installation design, Energy Management and refurbishment for a wide range of…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 8 | 20 contacts → | ||||
Partial evidence “HK Engineering Ltd is a leading engineering company specialising in electrical and gas testing and innovative solutions, with a solid commitment to excellence.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 9 | 14 contacts → | ||||
Partial evidence “Aylesford Electrical is a specialist testing, maintenance and installation provider based in Kent.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 10 | 11 contacts → | ||||
Indirect evidence “MET Group Technical provide a unique electrical energised inspection service to high & low voltage assets including your Power Distribution, Busbars, Submains & Fixed Wiring.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 11 | 10 contacts → | ||||
Partial evidence “Formed in 2012, Independent Company Safety Services (ICSS) Ltd specialise in Electrical Safety Compliance, and provides Portable Appliance Testing (PAT), Fixed Wire Testing…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 12 | 10 contacts → | ||||
Partial evidence “Electrical testing, installations, repairs & remedial works.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 13 | 9 contacts → | ||||
Indirect evidence “Formerly known as South West PAT Test LTD, TECC LTD are an electrical contracting company covering all aspects of commercial, industrial and domestic electrical needs, with a…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 14 | 5 contacts → | ||||
Indirect evidence “Welcome to Power Sonic Ltd If you require help and assistance with your electrical safety then you have come to the right place!” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 15 | 4 contacts → | ||||
Indirect evidence “At GRW we inspect and test electrical installations in commercial, industrial, public and residential rental premises, ensuring their compliance with BS 7671, and with statutory…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 16 | 4 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 17 | 4 contacts → | ||||
Indirect evidence “Since 1998 Inspexx Ltd has been a trusted partner in electrical inspections.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 18 | 3 contacts → | ||||
Indirect evidence “The company has a proud heritage of traditional skills and values fused with professional management.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 19 | 3 contacts → | ||||
Indirect evidence “We always honour our warranties, stick to our quotes and we always keep lines of communication open.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 20 | 3 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 21 | 3 contacts → | ||||
Indirect evidence “We are electrical contractors offering expert solutions in all aspects of electrical works.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 22 | 3 contacts → | ||||
Partial evidence “With years of experience in the inspection and testing industry, you can have confidence in our engineering inspections.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 23 | 3 contacts → | ||||
Partial evidence “PowerPlug is one of the oldest PAT Testing companies in the UK.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 24 | 3 contacts → | ||||
Partial evidence “industrial and commercial electrical installation,maintenance, inspection and testing” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 25 | 3 contacts → | ||||
Indirect evidence “Geo Therm Ltd provide non-invasive maritime and onshore Thermographic IRT Surveys, first pass High Voltage Partial Discharge (HVPD) inspections, hazardous area Ex Inspections, PAT…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
RevenueBase Smart Search
RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: insulation resistance testing services. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.
- Strong evidence
- The company's own public description of its business names insulation resistance testing services.
- Partial evidence
- Its own public description names part of insulation resistance testing services, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name insulation resistance testing services. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.
RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.
Showing 25 of 116 insulation resistance testing services based in the United Kingdom
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Insulation resistance testing services based in the United Kingdom at a glance
As of Sep 20, 2026Companies by employee count
Email recency for this list is measured worldwide rather than for United Kingdom, so it is reported there. Company counts and contact totals on this page are exact for United Kingdom, over 116 companies.
How this list was built
Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among insulation resistance testing services, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.
- Source
- The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
- What qualifies
- Companies headquartered in the United Kingdom whose own description of what they do matches “insulation resistance testing services”. Matching reads each company's description, not its industry code or its name.
- RevenueBase Smart Search
- RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names insulation resistance testing services), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
- What we exclude
- Companies whose own description does not clearly place them among insulation resistance testing services, and records with no verified work email. Companies headquartered outside United Kingdom are excluded even when they keep an office there.
- Match quality
- In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
- Ranking
- Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
- Verification
- Every listed company carries at least one verified work email, 226 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
- Refresh
- This page's figures were pulled from the company graph on September 20, 2026. Lists refresh periodically as the graph is re-checked.
- Corrections
- Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.
Frequently asked
What is RevenueBase Smart Search?
RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names insulation resistance testing services, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.
How many insulation resistance testing services are there based in the United Kingdom?
RevenueBase identified 116 insulation resistance testing services headquartered in the United Kingdom as of September 2026, matched on each company's own description of what it does rather than its industry code.
What is the largest company on this list?
Seaward, headquartered in Peterlee, tops this list with the largest team on record.
Which city has the most insulation resistance testing services?
London leads with 9 headquartered companies, followed by Hartlepool (3) and Manchester (3).
How do I get contact information for these companies?
A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 226 verified decision-maker contacts tracked across these 116 companies.
How current is this list?
The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 20, 2026.
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About this data
RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.
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