What is the difference between an LV and HV supply?
LV means low voltage and HV means high voltage. HSE guidance puts the dividing line at 1,000 volts for alternating current [S1]. Your supply classification depends on the agreed connection voltage. Taking an HV connection can bring responsibility for your own transformer and specialist operating arrangements, so confirm the asset boundary before accepting an offer [S2]. Checked October 2026.
What do LV and HV mean for your supply?
Low voltage (LV) and high voltage (HV) describe the voltage at which your site receives electricity. For alternating current (AC), HSE guidance defines LV as up to and including 1,000 volts, and HV as above that level [S1].
Why it matters for your site: accepting an HV connection can transfer equipment and operating responsibilities to your business. UK Power Networks’ HV guidance includes providing your own transformer, earthing arrangements and authorised persons [S2].
The classification does not describe how much electricity you use over a year. Read when a site needs a new substation for the wider project assessment.
When does a site need an HV connection?
Your distribution network operator (DNO), which manages the local network, assesses the requested demand and connection arrangement. Government guidance recommends discussing workplace and depot charging plans early [S3]. There is no universal charger-count trigger in that guidance.
A substation on your land does not by itself establish the voltage at which you take supply. Request the agreed point of supply, voltage and ownership boundary on the connection drawing. The HV responsibilities published by UK Power Networks distinguish customer equipment from network equipment [S2].
How do costs and ownership change?
Connection costs depend on capacity and distance from the existing network [S3]. Keep the construction price separate from the cost of equipment you will operate. Ask for these items to be identified:
- Transformer, switchgear and cables that your business will own.
- Earthing, testing and protection work included in the project.
- Maintenance arrangements and authorised operational cover.
- The completed site responsibility schedule [S2].
Use the grid upgrade cost guide to understand quotation scope. Check land rights and contractual responsibilities with your solicitor before accepting an equipment boundary.
Next step
Review meeting requirements without capital and prepare your connection records using the site check, then get matched with an installer that covers your area.
Piggy Pineapple Ltd operates this referral service. We refer enquiries to installer partners and may be paid a fee. Our owner holds shares in at least one partner. Before sharing your details, we name the proposed partner and disclose any shareholding in it.
Common questions
Is a low-voltage supply safe to touch?
No. LV is a voltage classification, not a safety permission. HSE's guidance requires precautions against electrical danger, including for low-voltage systems [S1].
Does HSE use the same boundary for direct current?
No. HSR25 gives a boundary of 1,500 volts for direct current, compared with 1,000 volts for alternating current. This entry concerns your network supply [S1].
Will installing more chargers automatically change your supply voltage?
No. Discuss the proposed demand with your network operator; it assesses the required connection works. Charger count alone does not establish a new supply arrangement [S3].
Who supplies the transformer for an HV connection?
UK Power Networks lists the customer's own transformer and associated cabling among customer responsibilities for its HV connections. Confirm the exact asset schedule in your offer [S2].
Who should take operational responsibility for private HV equipment?
UK Power Networks requires appointed authorised persons and a site responsibility schedule. Arrange competent operational cover before commissioning and check contractual duties with your solicitor [S2].
Ask about your site
Sources
- Electricity at Work Regulations - HSR25 guidance, paragraph 49, Health and Safety Executive,Last checked 19 October 2026
- Substations associated with HV and EHV connections, UK Power Networks,Last checked 19 October 2026
- Connecting electric vehicle chargepoints to the electricity network, UK Government,Last checked 19 October 2026