Company lists · Data refreshed September 2026

Top 25 Protective relay testing companies based in the United Kingdom

Name: Protective relay testing companies based in the United Kingdom
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 20, 2026 135 companies tracked

RevenueBase identified 135 protective relay testing companies headquartered in the United Kingdom as of September 2026 and tracks 743 professional contacts across them, including 265 with verified work emails. London is the largest hub.

This list covers protective relay testing companies 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.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 20, 2026 86% judged on-target in blind review

135Companies

743Contacts tracked

265Verified emails

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The 25 largest protective relay testing companies based in the United Kingdom

Ranked by team size

Top 25 of 135 protective relay testing companies based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 20, 2026. RevenueBase Smart Search rates how each company's information relates to protective relay testing companies: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Seaward	Partial evidence	Peterlee, United KingdomHQ checked Sep 20, 2026	51-200	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, 2026
2	Monitra	Partial evidence	Manchester, United KingdomHQ checked Sep 20, 2026	51-200	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, 2026
3	Pass LTD	Indirect evidence	Stockton-on-tees, United KingdomHQ checked Sep 20, 2026	51-200	47 contacts →
	Indirect evidence “PASS Limited offers a comprehensive solution for customers including test equipment, training and calibration.” Source: RevenueBase Database · checked Sep 20, 2026
4	Calbarrie Compliance Services LTD	Indirect evidence	Cheltenham, United KingdomHQ checked Sep 20, 2026	51-200	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, 2026
5	Pbsi Group LTD	Strong evidence	Manchester, United KingdomHQ checked Sep 20, 2026	51-200	35 contacts →
	Strong evidence “PBSI Group are a UK manufacturer with a long standing history of providing global customers with innovative protection relays and retrofit medium voltage circuit breaker solutions…” Source: RevenueBase Database · checked Sep 20, 2026
6	Group Management Electrical Surveys Limited	Indirect evidence	Halifax, United KingdomHQ checked Sep 20, 2026	11-50	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, 2026
7	Martindale Electric Co. LTD	Partial evidence	Watford, United KingdomHQ checked Sep 20, 2026	11-50	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, 2026
8	Micro Precision	Indirect evidence	Maidstone, United KingdomHQ checked Sep 20, 2026	51-200	27 contacts →
	Indirect evidence “Offering a comprehensive solution to meet the demands of Test & Measurement professionals both nationally and internationally, including Test Equipment Sales, Calibration…” Source: RevenueBase Database · checked Sep 20, 2026
9	Novus Compliance Services Limited	Partial evidence	Bishop Stortford, United KingdomHQ checked Sep 20, 2026	51-200	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, 2026
10	HK Engineering LTD	Partial evidence	Melksham, United KingdomHQ checked Sep 20, 2026	11-50	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, 2026
11	Aylesford Electrical Contractors LTD	Partial evidence	Maidstone, United KingdomHQ checked Sep 20, 2026	11-50	14 contacts →
	Partial evidence “Aylesford Electrical is a specialist testing, maintenance and installation provider based in Kent.” Source: RevenueBase Database · checked Sep 20, 2026
12	Northernhv	Indirect evidence	Hartlepool, United KingdomHQ checked Sep 20, 2026	1-10	14 contacts →
	Indirect evidence “Northern HV are a team of highly skilled professionals with many years of High Voltage and Electrical Commissioning experience.” Source: RevenueBase Database · checked Sep 20, 2026
13	Instrotech LTD	Indirect evidence	Watford, United KingdomHQ checked Sep 20, 2026	11-50	13 contacts →
	Indirect evidence “Tel:+44 (0)1923 442244 Email: sales@instrotech.com Instrotech is a specialist distributor of electrical and environmental test equipment representing all of the major brands.” Source: RevenueBase Database · checked Sep 20, 2026
14	MS Electrical Solutions	Indirect evidence	Bilton, United KingdomHQ checked Sep 20, 2026	1-10	13 contacts →
	Indirect evidence “Choose MS Electrical Solutions LTD for all your electrical install needs and benefit from a dependable service, expert support and quality workmanship, with projects delivered on…” Source: RevenueBase Database · checked Sep 20, 2026
15	Icss LTD	Partial evidence	Larne, United KingdomHQ checked Sep 20, 2026	11-50	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, 2026
16	Nationwide Compliance Solutions. Call ETM 01922 710014	Partial evidence	Cannock, United KingdomHQ checked Sep 20, 2026	51-200	10 contacts →
	Partial evidence “Electrical testing, installations, repairs & remedial works.” Source: RevenueBase Database · checked Sep 20, 2026
17	Fusion Electrical & Building Services Engineering	Indirect evidence	Merthyr Tydfil, United KingdomHQ checked Sep 20, 2026	11-50	9 contacts →
	Indirect evidence “Fusion Electrical & Building Services Engineering is a leading Electrical Services Company, based in South Wales and working throughout the UK.” Source: RevenueBase Database · checked Sep 20, 2026
18	The Electrical Compliance Collective LTD Tecc LTD	Indirect evidence	Swindon, United KingdomHQ checked Sep 20, 2026	11-50	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, 2026
19	Voltamp LTD	Partial evidence	Beckenham, United KingdomHQ checked Sep 20, 2026	11-50	8 contacts →
	Partial evidence “Voltamp are leading specialists in electrical testing, portable appliance testing PAT and fire alarm testing based in Kent, UK.” Source: RevenueBase Database · checked Sep 20, 2026
20	Electrical Distribution Solutions	Indirect evidence	Wolverhampton, United KingdomHQ checked Sep 20, 2026	1-10	6 contacts →
	Indirect evidence “We at Electrical Distribution Solutions deliver tailored solutions to the electrical distribution and control needs of business, large or small.” Source: RevenueBase Database · checked Sep 20, 2026
21	Power Sonic LTD	Indirect evidence	Driffield, United KingdomHQ checked Sep 20, 2026	1-10	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, 2026
22	Turnstone Electrical Services	Indirect evidence	Greenford, United KingdomHQ checked Sep 20, 2026	1-10	5 contacts →
	Indirect evidence “Set up in 2012, we have carried out many installations, mostly commercial & industrial, for a number of high profile clients such as Marks & Spencers, Wembley National Stadium and…” Source: RevenueBase Database · checked Sep 20, 2026
23	Vector Power Solutions LTD	Indirect evidence	Gateshead, United KingdomHQ checked Sep 20, 2026	1-10	4 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 20, 2026
24	Tidal Power Services LTD	Indirect evidence	Bournemouth, United KingdomHQ checked Sep 20, 2026	11-50	4 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 20, 2026
25	Frontline Electrical Services Limited	Partial evidence	St Neots, United KingdomHQ checked Sep 20, 2026	11-50	4 contacts →
	Partial evidence “Frontline Electrical Services Limited is a privately owned company specialising in a full range of electrical engineering, design, install, maintainance, testing and commissioning…” Source: RevenueBase Database · checked Sep 20, 2026

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: protective relay testing companies. 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 protective relay testing companies.
Partial evidence: Its own public description names part of protective relay testing companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name protective relay testing companies. 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 135 protective relay testing companies based in the United Kingdom

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Protective relay testing companies based in the United Kingdom at a glance

As of Sep 20, 2026

35.7%Verified-email coverage

5.5Average contacts per company

1-10Median size (employees)

7.4%Largest-city concentration · London

Sep 20, 2026Page data refreshed

Companies by employee count

1-10

11-50

51-200

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 135 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 protective relay testing companies, 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 “protective relay testing companies”. 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 protective relay testing companies), 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 protective relay testing companies, 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, 265 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 protective relay testing companies, 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 protective relay testing companies are there based in the United Kingdom?

RevenueBase identified 135 protective relay testing companies 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 protective relay testing companies?

London leads with 10 headquartered companies, followed by Manchester (3) and Bournemouth (2).

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 265 verified decision-maker contacts tracked across these 135 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.