Electric and hybrid high-voltage work: who should be doing it

Why this is not the same as a normal repair

HSE says the voltages present in electric and hybrid vehicles are significantly higher than those in other vehicles, currently up to 650 volts direct current against the usual 12 or 24 volts. Sources: ^[1]

HSE says that in dry conditions accidental contact with parts that are live at voltages above 110 volts direct current can be fatal. Sources: ^[1]

For motor vehicles, direct-current voltages between 60 and 1,500 volts are described as high voltage by both HSE and the Department for Transport. Sources: ^{[1] [2]}

HSE lists components that may retain a dangerous voltage even when the vehicle is switched off, and says some electronic components may store dangerous amounts of electricity even when the vehicle is off and the battery isolated. Sources: ^[1]

HSE says battery systems may contain chemicals that can be harmful if released and store significant amounts of energy that can give rise to explosion if not dealt with correctly. Sources: ^[1]

HSE warns that electric motors or the vehicle itself may move unexpectedly because of magnetic forces within the motors, and that people may be unaware of an electrically driven vehicle moving because it is silent. Sources: ^[1]

High-voltage cabling is usually orange, but the Department for Transport warns that non-compliance can occur, so orange cable is not a reliable sole indicator of where the high-voltage system runs. Sources: ^{[1] [2]}

What to do

• Do not start any task that could expose or disturb high-voltage components or cabling. Ask the garage whether the proposed task excludes the high-voltage system or requires work on it, and which named person is competent for that exact task.
• Do not touch, probe, cut, unplug or wash orange cabling or high-voltage components, and do not touch a damaged charging lead.
• Check the manufacturer’s guidance before any under-bonnet or underbody cleaning, because HSE warns that pressure washing has the potential to damage high-voltage components and cables.
• OBDCode UK publishes no procedure for isolating, disconnecting, testing or discharging a high-voltage system, and you should not attempt one.

Great Britain: competence and high-voltage work

In Great Britain, regulation 16 of the Electricity at Work Regulations 1989 requires that no person is engaged in a work activity where technical knowledge or experience is necessary to prevent danger or injury unless they possess that knowledge or experience, or are appropriately supervised. Sources: ^[4]

In Great Britain, regulation 3 places duties on employers and self-employed people so far as the Regulations relate to matters within their control, and requires employees while at work to co-operate with their employer and comply so far as matters are within their control. Sources: ^[3]

HSE separates work around electric and hybrid vehicles into four categories: valeting, sales and other lower-risk activities; incident response including emergency services and vehicle recovery; maintenance and repair excluding high-voltage electrical systems; and working on high-voltage electrical systems. Sources: ^[1]

HSE says the level of competence required varies greatly with the work, so awareness of the risks may be enough for sales or valeting, while people involved in repair and maintenance are likely to need a much greater level of competence. Sources: ^[1]

HSE says high-voltage systems should be isolated and proven dead by testing before any work is undertaken, using suitable insulated tools and test equipment, and that manufacturer instructions govern the method. Sources: ^[1]

HSE says working on live electrical equipment should be considered only when there is no other way for the work to be undertaken, and even then only if it is both reasonable and safe; the risks must be considered and suitable precautions implemented under the manufacturer’s instructions. Sources: ^[1]

HSE directs readers to the Institute of the Motor Industry for further information on qualifications and training in this area. Sources: ^[1]

No person shall be engaged in any work activity where technical knowledge or experience is necessary to prevent danger or, where appropriate, injury, unless he possesses such knowledge or experience, or is under such degree of supervision as may be appropriate having regard to the nature of the work.

What to do

• For work in Great Britain, ask how the garage will isolate and prove the system dead. If it says live work is unavoidable, ask why there is no alternative and how a competent person will control the risk under the manufacturer’s instructions; HSE’s exception is narrow, not a shortcut or DIY permission.
• A garage saying it cannot take the job is a normal and correct answer here, not a brush-off.

This is the Great Britain work-safety branch. Northern Ireland uses the separate branch below.

Northern Ireland: competence, isolation and testing

In Northern Ireland, regulation 16 of the Electricity at Work Regulations (Northern Ireland) 1991 says a person must not be engaged in work where technical knowledge or experience is necessary to prevent danger or injury unless they possess that knowledge or experience or are under an appropriate degree of supervision for the nature of the work. Sources: ^[5]

HSENI’s general electrical-safety guidance says only competent persons should carry out work on electrical systems and that isolation and testing should take place before work on electrical equipment. Sources: ^[6]

HSENI identifies the Electricity at Work Regulations (Northern Ireland) 1991 as the key legislation accompanying that Northern Ireland electrical-safety guidance. Sources: ^[6]

A person shall not be engaged in any work activity where technical knowledge or experience is necessary to prevent danger or, where appropriate, injury, unless he possesses such knowledge or experience, or is under such degree of supervision as may be appropriate for that purpose having regard to the nature of the work.

Only competent persons should carry out work on electrical systems. Isolation and testing should take place before working on electrical equipment.

What to do

• For work in Northern Ireland, ask which named person is competent for the exact electrical work and how isolation and testing will be completed before work starts.
• Treat HSENI’s page as a general electrical-safety baseline, not as an EV isolation procedure. Check the manufacturer’s model-specific information and do not attempt isolation, testing or live work yourself.

Do not cite the Great Britain 1989 Regulations as Northern Ireland law; this branch uses the 1991 Northern Ireland Regulations and HSENI.

What an industry register can and cannot tell you

The IMI Professional Register lists individual members and their place of work, recognised for their achievements, experience, professionalism and for keeping knowledge and skills up to date through continuing professional development. Sources: ^[12]

IMI says that to remain on the Professional Register a member must evidence continued learning and development, with a minimum of 90 CPD credits over a three-year period. Sources: ^[12]

IMI describes TechSafe as recognition within the Professional Register for competence and commitment to learning in safety-critical technologies including electric, hybrid, hydrogen and ADAS-equipped vehicles. Sources: ^[13]

IMI says TechSafe recognition is gained through an eligible qualification or IMI accreditation and is retained through specific CPD requirements over a three-year cycle. Sources: ^[13]

IMI says TechSafe recognition is shown in a member’s Professional Register digital card, which is where a claim on a business card or website can be checked. Sources: ^{[13] [12]}

The Great Britain and Northern Ireland regulation 16 tests are technical knowledge or experience, or appropriate supervision; neither regulation names IMI membership or TechSafe as a legal condition, and HSE points to IMI only for further information on qualifications and training. Sources: ^{[4] [5] [1]}

What to do

• Search the register for the named individual who will do the work, not only for the business, and check the entry is current.
• Check the digital card shows the relevant TechSafe category for electric vehicles, then verify that the underlying qualification or IMI accreditation covers this exact job rather than a different level or type of work.
• Treat the register entry and underlying achievement as verifiable Grade B industry evidence about one person. Neither IMI membership nor TechSafe recognition is a licence or a statutory condition for this work, and neither is sufficient on its own to prove task-specific competence.
• Also check current experience, any supervision needed, access to manufacturer-specific information, and whether the workshop, tools, insurance and storage arrangements suit the job.
• A logo on a website or a certificate on a wall is a claim to verify in the register, not the verification itself.

The register is a neutral verification route for industry evidence. It does not licence high-voltage work or replace a task-specific competence assessment.

Check an individual on the IMI Professional Register

Manufacturer network or independent specialist

HSE says there are substantial differences in the designs of electric and hybrid vehicles from different manufacturers, and that having information specific to the manufacturer and the vehicle being worked on is important in identifying what actions are necessary to work safely. Sources: ^[1]

HSE tells those doing high-voltage work to refer to vehicle-specific sources of information from the manufacturer, and trade bodies, to identify the precautions needed to prevent danger. Sources: ^[1]

The Department for Transport says many electric vehicles have an emergency response guide that can be downloaded from the manufacturer’s website, which identifies where high-voltage systems are located and carries additional emergency safety information. Sources: ^[2]

GOV.UK says that if a vehicle has a serious safety defect the manufacturer will write to tell you what to do, that you must not drive the vehicle, and that you will not usually pay for recall repairs or parts. Sources: ^[11]

What to do

• A franchised or manufacturer-authorised workshop is the natural route where the job touches a recall, a software or battery-management update, a warranty claim, or replacement of the traction battery pack itself.
• An independent specialist is a normal route for diagnosis, for out-of-warranty work and for older hybrids, provided the named person doing the high-voltage part can evidence competence for that exact job and has manufacturer data for your model.
• Ask which of the two the job actually needs before you pay for diagnosis twice.
• Check for an outstanding safety recall in the official GOV.UK service before you authorise any paid high-voltage work.

OBDCode UK does not recommend, rank or receive commission from any dealer, garage, specialist or recovery operator.

Check if a vehicle, part or accessory has been recalled

Smell, noise, smoke or a collision: stop and call 999

Department for Transport guidance for recovery operators says that in the event of flame, ejection of gas or other material, a smell of irritating chemicals, or unexpected noises such as the loud hiss of a release of gas, all assessment and checks should be abandoned, people should retreat to safety and the fire service should be called. Sources: ^[2]

The same guidance says the absence of those signals, or of any discernible elevated temperature, may not indicate a complete absence of thermal risk. Sources: ^[2]

The Department for Transport says emergency services need to attend if a vehicle is on fire, has been on fire, or there is a possibility that a fire could start, and that a battery fire or vapour cloud explosion should not be tackled by an untrained person. Sources: ^[2]

It says that in the event of any electric vehicle fire the correct action is to defer to the fire service, evacuate everyone around the vehicle and retreat to a safe place well away and upwind from the fire and any smoke or fumes. Sources: ^[2]

It says a battery fire is highly likely to release hydrogen fluoride gas and other harmful compounds, which can irritate the eyes, nose and throat and at high enough levels can be fatal, and that people should stay well clear of a burning vehicle and away from any fumes, smoke or vapour. Sources: ^[2]

It says airbag deployment is a good indicator that the high-voltage system should be inactive, but that there is currently no requirement for a vehicle to have an indicator showing whether the high-voltage system has been deactivated, and an electrical hazard can exist where high-voltage components or cables were damaged or exposed in a serious incident. Sources: ^[2]

It says electric vehicles can reignite hours or even days after an incident, and records instances of vehicles igniting up to three weeks after an accident because of internal damage caused at the time. Sources: ^[2]

GOV.UK says its Highway Code applies to England, Scotland and Wales; the following Highway Code actions are therefore the Great Britain road branch, not Northern Ireland instructions. Sources: ^[7]

For England, Scotland and Wales, the Highway Code says that if you need to stop because of a breakdown or incident you should try to stop in a place of relative safety, and that you and your passengers should where possible keep well away from the vehicle and moving traffic. Sources: ^[8]

On a motorway in England, Scotland or Wales, the Highway Code says to exit by the side furthest from traffic only if it is safe and possible, get behind a safety barrier where there is one, not return to the vehicle or attempt repairs, and call 999 immediately and ask for the police if you cannot leave the vehicle or are not near a free emergency telephone. Sources: ^[8]

For England’s strategic road network, National Highways says that if it is not safe to exit because the vehicle cannot reach the left lane or a place of relative safety, people should stay in the vehicle, keep their seat belts and hazard warning lights on, and call 999 immediately asking for the police. Sources: ^[9]

For England, Scotland and Wales, if you are involved in an incident or collision, the Highway Code says to use hazard warning lights, contact the emergency services on 999 with full details of the location and any casualties, move uninjured people away from the vehicles to a place of relative safety, and stay at the scene until the emergency services arrive. Sources: ^[8]

In the event of flame or ejection of gas or other material, smell of irritating chemicals, or unexpected noises such as the loud hiss of a release of gas, abort all assessment and checks, retreat to safety and call the fire service.

Evacuate all people around the vehicle and retreat to a safe place well away and upwind from the fire and any smoke or fumes.

SafetyClass Red — do not attempt high-voltage work; no DIY procedure is published.

DriveAdvice Stop — if a high-voltage/traction-battery fault or required high-voltage work brings this guide into scope, do not drive the vehicle to a garage; arrange recovery.

This page deliberately stops at general safety actions that have an authoritative source behind them. Anything beyond that — which switch, which fuse, which service disconnect — belongs to the manufacturer’s handbook, the manufacturer’s emergency response guide and the emergency services, not to a website that has never seen your vehicle.

What to do

• A burning or acrid smell, hissing, popping, sparking, smoke or vapour from an electric or hybrid vehicle means stop in a place of relative safety if possible, abandon any inspection and call 999. If it is safe to leave, get everyone well away and upwind; on a motorway, follow the matching Great Britain or Northern Ireland branch and do not step into moving traffic.
• Do not try to fight a battery fire yourself; official guidance reserves that for fire service personnel with specialist training and breathing apparatus.
• Tell the 999 operator, and later the recovery operator and the garage, that the vehicle is electric or hybrid and describe anything you smelled, heard or saw.
• After any impact to the underside or the battery area, have the vehicle assessed even if it drives and shows no warning, because a thermal event can be delayed.
• If a warning about the high-voltage or traction battery system appears while driving, stop somewhere safe as soon as you can and follow the vehicle handbook for that specific warning rather than a general rule from any website.
• If the vehicle is plugged in when the problem appears, and it is safe to reach the charge point controls, stop the charge at the unit; report a damaged public charge point to its operator and do not handle a damaged lead.

Northern Ireland: use the separate road-incident branch

Northern Ireland Highway Code rule 274 says that after a breakdown on an ordinary road you should get the vehicle off the road if possible, use hazard warning lights if it is causing an obstruction, and never use a warning triangle on a motorway. Sources: ^[10]

On a Northern Ireland motorway, rule 275 says that if the vehicle reaches the hard shoulder, occupants should leave by the left-hand door, keep away from the carriageway and hard shoulder, not attempt even simple repairs, use the emergency telephone in preference to a mobile, then return and wait near the vehicle well away from the carriageway and hard shoulder. Sources: ^[10]

Northern Ireland rule 277 says that if the vehicle cannot get onto the hard shoulder, you should not place a warning device on the carriageway, should switch on hazard warning lights, and should leave the vehicle only when you can safely get clear of the carriageway. Sources: ^[10]

Northern Ireland rule 278 says that a driver whose disability prevents following the preceding advice should stay in the vehicle, switch on hazard warning lights, and display a Help pennant or contact the emergency services and be ready to give the location. Sources: ^[10]

For a collision in Northern Ireland, rule 283 says to use hazard warning lights, arrange for the emergency services to be called immediately with the location and casualty details, move uninjured people to safety, and stay until the emergency services arrive. Sources: ^[10]

What to do

• In Northern Ireland, follow rules 275 to 278 in this section. After using the hard-shoulder emergency telephone, rule 275 says to return and wait near the vehicle, well away from the carriageway and hard shoulder.
• If the vehicle cannot reach the hard shoulder, switch on the hazard warning lights and leave only when you can safely get clear of the carriageway. If a disability prevents following the preceding advice, stay in the vehicle, keep the hazard warning lights on and contact the emergency services or display a Help pennant.

The Great Britain and Northern Ireland codes conflict on returning to the vehicle after calling for help, so their motorway instructions are stated separately and are not combined.

nidirect — Northern Ireland breakdowns and incidents rules

Getting it moved without making it worse

The Department for Transport says its guidance is a reference for professionals involved in roadside recovery; it is not exhaustive, is not a training document and should not be used instead of suitable training. Sources: ^[2]

The same guidance says first and second responders should receive suitable safety training for electric-vehicle recovery, and that recovery professionals should recognise the limits of their knowledge and experience and not attempt work beyond their training. Sources: ^[2]

The Department for Transport says it is not recommended to tow electric vehicles on their wheels, because doing so can generate electrical current and damage the high-voltage systems. Sources: ^[2]

HSE gives the same warning for recovery work, saying towing should be avoided unless it can be determined to be safe because dangerous voltages can be generated by movement of the drive wheels. Sources: ^[1]

The Department for Transport says the recommended method of transportation is on a flatbed or trailer, or by using dolly wheels, and that the manufacturer’s instructions or emergency response guide should always be consulted. Sources: ^[2]

Within that professional-recovery context, the Department for Transport allows an electric or hybrid vehicle to be towed or pushed on its wheels a short distance out of immediate danger, such as a live traffic lane, only at walking pace, only for the minimum distance, only with the transmission in neutral and the parking brake released, and only where the vehicle has not been in a collision and is not visibly damaged. Sources: ^[2]

It says some heavier vehicles have a means of disconnecting the drive axles from the electric motors so they can be towed safely on their wheels, which is a vehicle-specific feature rather than a general rule. Sources: ^[2]

Before recovery starts, the Department for Transport says keyless entry fobs should be placed in a signal-blocking pouch, and notes that smartphone apps may also interact remotely with the vehicle. Sources: ^[2]

HSE says that during recovery onto a recovery vehicle the remote operation key should be removed to a suitable distance and the standard 12 or 24 volt battery disconnected to prevent the vehicle being activated. Sources: ^[1]

Recovery cover, courtesy cars and onward travel are outside the scope of this page; it covers only the high-voltage constraints on how the vehicle is moved.

What to do

• When you book recovery, say that the vehicle is electric or hybrid before anything is dispatched, and ask whether a flatbed, trailer or dolly wheels will be used.
• The Department for Transport’s short-move conditions appear in guidance for recovery professionals and are not DIY permission. Do not push or tow the electric or hybrid vehicle yourself; leave any decision and movement to a recovery professional who confirms suitable EV-recovery safety training, competence for this situation and use of the manufacturer’s instructions or emergency response guide.
• Great Britain branch (England, Scotland and Wales): on a motorway, exit by the side furthest from traffic and get behind a safety barrier only if it is safe and possible to do so. Keep passengers away from traffic, do not return to the vehicle or attempt repairs, and if you cannot leave the vehicle or are not near a free emergency telephone call 999 immediately and ask for the police.
• England strategic-road unsafe-exit branch: where the National Highways advice applies, if anyone cannot safely follow the exit advice, stay in the vehicle, keep seat belts and hazard warning lights on, and call 999 immediately asking for the police.
• For Northern Ireland, use only the separate rule 275, 277 and 278 road branch above.
• Hand over the keys and mention any phone app that can wake the vehicle, so the operator can keep it from powering up.
• Ask where the vehicle will be stored and tell the operator about any smell, noise or impact, because that changes how they handle and park it.

Questions to ask before you authorise anything

Battery state-of-health readings, warranty cover on a traction battery and goodwill claims are handled separately from this page. Keep the written evidence from this job either way.

Checklist

• Will the high-voltage part of this job be done here, and who by, by name?
• What evidence shows that person is competent for this exact job? If IMI recognition is offered, does the digital card show the electric-vehicle category and does the underlying qualification or accreditation cover the work?
• Do you have manufacturer-specific data and the emergency response guide for this model and year?
• Has the vehicle been checked for an outstanding safety recall relevant to this fault?
• Does the diagnosis need the high-voltage system opened at all, or is this a 12-volt, cooling or software fault?
• Is the first charge diagnosis only, and what is the written estimate for labour, parts, VAT and any calibration?
• How will the vehicle be transported if it cannot be driven, and who pays for that?
• If the traction battery pack has to go to the manufacturer, who handles it, how long, and where is the vehicle stored meanwhile?
• What is the approval limit above which you must contact me before doing more?

Important

This is general guidance, not legal advice, and it is not a repair procedure.

Nothing on this page authorises you to work on a high-voltage system. If in doubt, stop, keep people away from the vehicle and call the vehicle manufacturer’s assistance line or, where there is any sign of fire, gas or chemical smell, 999.