In the world of electrical systems, understanding the classifications of high voltage (HV) and low voltage (LV) is essential for anyone working in industries that rely on power transmission and distribution. These classifications shape not only how electrical systems are designed and operated but also how safety is managed at every level. Whether you’re an engineer, a technician, or a facilities manager, knowing the ins and outs of HV and LV can mean the difference between a well-run operation and a potentially hazardous work environment.
When we talk about low voltage, or LV, we’re generally referring to systems that handle up to 1000V AC or 1500V DC. This is the type of voltage most of us encounter daily in homes and commercial buildings. In Europe, for instance, typical single-phase LV systems are 110 or 230 volts, while three-phase systems operate at 400 volts. These LV systems are ideal for smaller scale power needs, balancing efficiency and safety in settings where electrical demand isn’t too high.
In the UK, and many other regions across the globe, high voltage (HV) is determined as anything in excess of 1000V. It is quite common for this to be further broken down into medium voltage (MV), high voltage (HV), and extra high voltage (EHV).
As we scale up, we enter the realm of medium voltage (MV), typically ranging between 1000V and 35kV, commonly used in industrial facilities. But for large scale power transmission, high voltage (HV) is essential. HV systems, ranging from 35kV up to around 230kV, are the backbone of long distance power transmission networks. By reducing power losses over distance, HV systems make it possible to send electricity efficiently across cities, countries, and even continents. Above 230kV, we reach extra high voltage (EHV), used for extensive power transmission across regions.
Each voltage level brings unique challenges. LV systems are relatively safe, but HV systems require specialised equipment and rigorous safety protocols due to the higher risk of electrical arcing, which can be incredibly dangerous. This is where comprehensive training, such as EPIT’s HV/LV courses, becomes invaluable.

For professionals working with HV and LV systems, EPIT offers several targeted courses to address the specific needs of different roles and industries. These courses not only provide critical skills for safe operations but are also accredited by respected bodies like City & Guilds, ensuring that EPIT’s training meets high standards recognised across industries. For professionals, this accreditation adds credibility to their qualifications and makes EPIT’s courses valuable in terms of career advancement.
1. HV/LV Safe Working Practices Awareness Course
EPIT’s HV/LV Safe Working Practices Awareness Course provides participants with practical and theoretical training in handling both HV and LV systems. The course covers fundamental safety protocols, HV/LV switching techniques, and isolation procedures, giving professionals hands-on experience with real equipment. This training is designed for a broad range of roles, from maintenance technicians to electrical engineers, and is ideal for professionals working in power generation, industrial, and marine environments.
2. High Voltage Safe Working Practices (ROV)
For those working in remote or offshore environments, EPIT offers the High Voltage Safe Working Practices (ROV) course. This course is tailored for professionals operating remotely operated vehicles (ROVs) in offshore settings, where HV exposure is common. Participants learn the specific high voltage safety practices necessary for ROV operations, with a strong focus on hazard awareness and emergency procedures. This course equips offshore workers with the skills to handle high voltage in challenging environments, ensuring safety and regulatory compliance even in remote locations.
3. HV/LV Electrical Protection
EPIT’s HV/LV Electrical Protection Course focuses on the protection and control systems within HV and LV environments. Designed for professionals responsible for the maintenance and operation of protection systems, this course covers relay protection, circuit breakers, and fault response strategies. With a combination of theoretical learning and practical exercises, the course enables participants to understand and manage protection systems effectively, safeguarding equipment and personnel.
4. HV/LV Safe Working Guidance
The HV/LV Safe Working Practice Guidance course at EPIT is ideal for those seeking to deepen their understanding of safe working practices in both high and low voltage environments. This course provides updated guidance on safety protocols, isolation procedures, and HV/LV switching. Participants gain insights into the latest industry standards and regulatory requirements, making it an excellent choice for professionals looking to enhance their safety knowledge or those preparing for supervisory roles in HV/LV environments.

Aberdeen is renowned as a hub for the oil and gas industry and, more recently, for renewable energy developments. This means that demand for HV/LV certified professionals is particularly high in the region, especially within power generation, offshore oil and gas, and wind energy sectors. For those seeking HV/LV training in Aberdeen, EPIT’s accredited courses are an ideal choice, aligning with the local industry’s needs for skilled and certified professionals.
As renewable energy continues to expand, especially offshore wind, and as the oil and gas sector remains strong, Aberdeen requires a workforce skilled in high-voltage systems. EPIT’s courses are designed to meet this demand, helping professionals achieve the qualifications needed to work safely and efficiently in these dynamic and challenging environments.
1. Why is HV/LV certification important?
HV/LV certification ensures that professionals are equipped to handle electrical systems safely, in compliance with health and safety legislation, including the Electricity at Work Regulations 1989. This certification is critical in industries with high-risk environments like oil and gas, offshore, and renewable energy.
2. Who needs HV/LV certification?
Professionals working with the installation, maintenance, and testing of HV/LV equipment, such as electrical engineers, maintenance technicians, and facilities managers, typically require HV/LV certification.
3. What types of HV/LV courses are available at EPIT?
EPIT offers a range of courses, including the HV/LV Safe Working Practices Awareness Course, High Voltage Safe Working Practices (ROV), HV/LV Electrical Protection, and HV/LV Safe Working Practices (Guidance 2024), each tailored to specific industry and job requirements.

4. Are EPIT’s courses recognised within the industry?
Yes, EPIT’s HV/LV courses are accredited by City & Guilds and utilised by many major operations and service companies, giving them industry recognition and enhancing career prospects for certified professionals.
5. What are the prerequisites for enrolling in an HV/LV course?
The prerequisites vary depending on the course, but generally, participants are expected to have a background in electrical, instrument, or mechanical fields. Some prior experience with HV or LV systems is beneficial, especially for advanced courses. Basic safety knowledge is also essential, and since the courses are taught in English, a working proficiency in the language is required. For physically demanding courses, participants may need to be in good physical condition to perform practical exercises.
6. How often do I need to renew my HV/LV certification?
A certificate is valid for 5 years, to schedule your course to renew your certificate, get in touch with the team at EPIT.
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Posted on Googlemichael casson11 March 2026Trustindex verifies that the original source of the review is Google.
Great presentation by the instructors and prep for Compex 01 - 04 examination. Highly recommendedPosted on GoogleViaceslav Gaiducenia12 January 2026Trustindex verifies that the original source of the review is Google.
I did compex 01-04. English is not my first language. I got extra support, a bit of extra explonation, extra advice. All of this was super helpful. The instructors were very knowlagable, passionate and well tempered. I failed one of the units but I passed it second time.Posted on GoogleCameron Bowyer18 November 2025Trustindex verifies that the original source of the review is Google.
I had an excellent experience training with EPIT Aberdeen. The instructors were incredibly knowledgeable, professional, and clearly passionate about what they do. The facilities and equipment are top-quality, and the training was delivered in a way that was both practical and engaging. Everything was explained thoroughly, with real-world examples that made the content easy to understand and apply. The staff were friendly and supportive throughout, creating a really positive learning environment. I left feeling confident, well-prepared, and genuinely impressed with the standard of training. Highly recommend EPIT Aberdeen to anyone looking for high-quality, industry-leading courses.Posted on GoogleShawn Clark12 September 2025Trustindex verifies that the original source of the review is Google.
Done the CompEx Ex01-Ex04 with Mike and Dodd, and they were both excellent! They both broke things down and made them easier to understand, as well as being genuinely good people who you can have a normal conversation and laugh with!Posted on GoogleJohn Soutar11 June 2025Trustindex verifies that the original source of the review is Google.
An absolutely brilliant training and test facility that made the dreaded "Compex Refresher" course, a far more enjoyable and beneficial experience. From the great training material to the very knowledgeable instructors, it all helped to teach us about the new practices and standards in Compex and I certainly left knowing more than I did when I walk through the door Monday morning. Thanks to the all staff! 5*Posted on GoogleQuinn MacDonald30 April 2025Trustindex verifies that the original source of the review is Google.
Excellent facilities and the instructors were brilliant at teaching you the course materials along with real world advice and practicesPosted on GoogleAndrei Lerca4 March 2025Trustindex verifies that the original source of the review is Google.
Great training center powered by passionate people and a very beautiful reception.Posted on Googlejames Lombardo27 November 2024Trustindex verifies that the original source of the review is Google.
Most reliable and Very professionalPosted on GoogleAlistair Strachan (Ally)17 September 2024Trustindex verifies that the original source of the review is Google.
Been here twice, superb facilities and certainly the best out of the 3 different venues I've attended for compex.
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Gases & Vapours (EX01 – Ex04)
Electrical / Instrument Craftpersons & Engineers Install, Inspect & Maintain: Gas & Vapours
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| Industries | Principal to all Ex environments, with direct application in hazardous vapour and gas environments. |
| Entry Qualifications Guidance | Level 3, ECS Gold Card, National Diploma or equivalent.
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Gases & Vapours (EX01 – Ex04)
Electrical / Instrument Craftpersons & Engineers Install, Inspect & Maintain: Gas & Vapours
| Header Column #1 | |
|---|---|
| Industries | Principal to all Ex environments, with direct application in hazardous vapour and gas environments. |
| Entry Qualifications Guidance | Level 3, ECS Gold Card, National Diploma or equivalent.
Disipline:
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| Entry Knowledge - Expected |
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| Entry Skills - Expected |
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| Job Roles Aspiring to or operating in |
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| Entry Experience Guidance |
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| Entry Knowledge - Desirable |
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| Entry Skills - Desirable |
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