Plant rooms and switchgear areas are essential parts of many commercial and industrial buildings. They house equipment used to distribute electricity, control building services and support the safe operation of electrical installations.

From office buildings and hospitals to warehouses, factories and large commercial premises, these areas may contain electrical distribution boards, switchgear, transformers, control panels and other specialist equipment.

Choosing the right electrical hazard signs for plant rooms and switchgear areas helps communicate risks to maintenance teams, contractors, facilities staff and other people who may approach the equipment.

But which signs should you display? Is a general Danger Electricity Sign sufficient? When should you use a High Voltage Warning? And what additional notices may be needed for restricted access or electrical maintenance?

This guide explains the main sign types, where they may be appropriate and what to check before placing an order.

Why Are Electrical Hazard Signs Important in Plant Rooms?

Plant rooms can contain several different hazards within a relatively small space.

Depending on the installation, these may include:

• Live electrical equipment.

• Electrical distribution boards.

• Low-voltage or high-voltage switchgear.

• Transformers.

• Electrical control cabinets.

• Exposed electrical hazards during maintenance.

• Equipment requiring safe isolation.

• Restricted access areas.

Electrical hazard signs help communicate relevant risks before people approach or enter an area.

They can also reinforce access restrictions and identify equipment that requires particular precautions.

However, signage should support suitable electrical design, maintenance, risk assessment, access controls and safe working procedures.

An electrical warning sign does not make an unsafe installation safe.

Which Electrical Hazard Signs Should Be Displayed in a Plant Room?

There is no single combination of signs suitable for every plant room.

The correct selection depends on the equipment, operating voltages, hazards and applicable safety requirements.

The following are the main categories to consider.

1. Danger Electricity Signs

A Danger Electricity Sign provides a general warning that an electrical hazard is present.

It commonly features a black lightning bolt inside a yellow warning triangle.

The recognised electrical hazard warning symbol is identified as W012 in BS EN ISO 7010.

Where Might Danger Electricity Signs Be Used?

Depending on the installation and risk assessment, suitable locations may include:

• Electrical plant room entrances.

• Switchgear room doors.

• Electrical distribution areas.

• Control panel enclosures.

• Electrical equipment cabinets.

• Relevant maintenance access points.

A Danger Electricity Sign may be appropriate where people need to recognise an electrical hazard but a more specific voltage warning is not necessary.

Buying tip: Choose a warning that accurately describes the installation rather than automatically using High Voltage wording.

2. High Voltage Warning Signs

Some plant rooms and switchgear areas contain high-voltage electrical equipment.

In these locations, a Danger High Voltage Sign may be appropriate.

High-voltage warnings provide more specific information than a general electrical hazard sign.

Typical Applications

• High-voltage switchgear rooms.

• Transformer enclosures.

• Substation access points.

• Industrial high-voltage installations.

• Relevant electrical testing areas.

Does Every Switchgear Room Need a High Voltage Sign?

No.

Switchgear can operate at different voltage levels.

Many commercial buildings contain low-voltage switchgear.

In the context of the Electricity at Work Regulations 1989, high voltage generally means voltage exceeding 1,000 volts AC or 1,500 volts DC.

A High Voltage Sign should only be selected where the wording accurately reflects the installation.

Lower-voltage equipment can still present serious electrical hazards.

3. Danger of Death & Electric Shock Warning Signs

Some installations may require particularly prominent electrical warnings.

Relevant messages can include:

• Danger of Death.

• Risk of Electric Shock.

• Danger Live Electrical Equipment.

• Danger Electricity.

These signs communicate related but different messages.

Danger of Death Signs

A Danger of Death Sign emphasises that the electrical hazard could have fatal consequences.

Electric Shock Risk Signs

An Electric Shock Risk Sign identifies the risk of electrical shock.

The correct message depends on the hazard, location and intended audience.

Avoid selecting the most dramatic wording simply because it appears more noticeable.

4. Authorised Personnel Only Signs

Plant rooms and switchgear areas often require controlled access.

An Authorised Personnel Only Sign communicates that entry is restricted to people with appropriate permission.

These notices may be relevant to:

• Electrical switchgear rooms.

• Transformer rooms.

• Restricted plant areas.

• Electrical maintenance rooms.

• Specialist equipment enclosures.

Are Access Restriction Signs Enough?

No.

Where access needs to be controlled, signage should support appropriate locks, barriers, supervision and other security measures.

An Authorised Personnel Only notice does not physically prevent entry.

5. Keep Clear & Do Not Obstruct Signs

Electrical plant rooms and switchgear areas may require clear access to equipment for operation, inspection, maintenance or emergency procedures.

Depending on the circumstances, suitable notices may include:

• Keep Clear.

• Do Not Obstruct.

• Keep Access Clear.

• No Storage.

These signs may help discourage people from leaving materials in front of electrical equipment.

Where Are Keep Clear Signs Useful?

They may be relevant near:

• Switchgear access doors.

• Electrical distribution boards.

• Control panels.

• Emergency operating equipment.

• Designated access routes.

The correct working clearances should be established through the relevant design and safety requirements.

A Keep Clear Sign does not establish the necessary clearance distance.

6. Electrical Isolation & Maintenance Signs

Electrical work may require equipment to be isolated before maintenance or inspection.

Relevant signs and notices can include:

• Do Not Switch On.

• Isolate Main Supply.

• Electrical Equipment Under Maintenance.

• Danger Live Electrical Equipment.

• Other suitable operational instructions.

These notices serve a different purpose from permanent electrical hazard warnings.

Permanent vs Temporary Notices

A permanent Danger Electricity Sign identifies an ongoing hazard.

A temporary Do Not Switch On notice may communicate an instruction during a particular maintenance activity.

Temporary notices should be used within a suitable safe system of work.

A Do Not Switch On Sign alone does not isolate electrical equipment or prevent it from being re-energised.

Electrical Plant Room Signs vs Switchgear Room Signs

Although the terms are sometimes used together, plant rooms and switchgear rooms can have different functions.

Electrical Plant Rooms

A plant room may contain electrical controls alongside other building services equipment.

The required signs depend on the equipment and hazards present.

Switchgear Rooms

A switchgear room is specifically associated with electrical switching, control and distribution equipment.

The signage may need to communicate electrical hazards, operating voltage and access restrictions.

Sign Selection Comparison

These are illustrative examples rather than a universal legal checklist.

Where Should Electrical Hazard Signs Be Positioned?

Correct placement helps ensure warnings are recognised before people encounter the hazard.

At Plant Room Entrances

Where an electrical hazard warning is required, displaying it at the entrance can help people recognise the risk before entering.

On Switchgear Enclosures

Relevant warnings may be positioned on switchgear doors, panels or equipment enclosures.

The sign should be visible before people access the equipment.

At Restricted Access Points

Where entry is controlled, access restriction notices should be positioned where people can see them before entering.

Near Relevant Equipment

Some hazards may require more specific warnings at individual pieces of equipment.

For example, a high-voltage enclosure may require a warning that differs from a general plant room entrance notice.

Consider Multiple Entrances

Large plant rooms may have more than one entrance.

Check whether each relevant approach requires suitable signage.

Avoid Obstructions

Signs should not be hidden by:

• Open doors.

• Machinery.

• Pipework.

• Stored materials.

• Other notices.

Buying tip: Walk through the normal approach routes before deciding how many signs to order.

What Size Electrical Hazard Signs Do You Need?

Plant rooms and switchgear areas vary considerably in size.

A warning on a small control panel may be viewed from close range, while a sign at the entrance to a large industrial switchgear room may need to be recognised from further away.

Smaller Signs

May be suitable for equipment panels, cabinets and close-range warnings.

Medium Signs

May be appropriate for plant room doors, equipment enclosures and internal entrances.

Larger Signs

May be needed where the warning must be recognised from a greater distance.

Factors to Consider

• Viewing distance.

• Mounting height.

• Available space.

• Lighting conditions.

• Sign legibility.

• Environmental conditions.

There is no single sign size suitable for every plant room or switchgear installation.

Choosing Electrical Hazard Sign Materials

The correct material depends on the mounting surface and environment.

Self-Adhesive Vinyl Signs

Self-adhesive signs may be suitable for compatible smooth, clean surfaces such as equipment panels and cabinet doors.

Rigid Plastic Signs

Rigid plastic signs may be useful for walls, plant room entrances and other locations requiring a mounted signboard.

Other Materials

Selected electrical warning signs at The Sign Shed are available in additional materials, including recycled plastic, Foamex and aluminium composite.

Check the individual product specifications for available sizes, materials and fixing options.

What About Outdoor Switchgear?

Outdoor installations may require materials and fixings suitable for exposure to weather and other environmental conditions.

Don't assume every sign material is suitable for outdoor use.

Electrical Hazard Signs for Different Buildings

Different building types may require different approaches to electrical signage.

Offices & Commercial Buildings

Commercial buildings may contain electrical plant rooms serving lighting, heating, ventilation and other services.

Signs can help communicate electrical hazards and identify restricted areas.

Factories & Industrial Premises

Industrial sites may contain electrical distribution equipment, motor control centres, transformers and specialist switchgear.

Signage should reflect the specific hazards and remain visible in busy working environments.

Warehouses & Distribution Centres

Warehouses may contain electrical plant rooms, control equipment and distribution boards.

Suitable warning and access notices can help communicate hazards to maintenance staff and other workers.

Hospitals & Healthcare Facilities

Healthcare buildings may have electrical installations supporting critical services.

Clear identification and appropriate warning signs can help maintenance teams locate equipment and recognise relevant hazards.

Schools, Colleges & Universities

Educational premises may contain electrical plant rooms and switchgear areas near areas used by pupils, students or visitors.

Access restrictions and suitable warnings should reflect the installation and who may encounter the area.

Are Electrical Hazard Signs Legally Required in Plant Rooms?

UK electrical safety is governed by several legal requirements.

The Electricity at Work Regulations 1989 establish duties relating to electrical systems and work activities.

The Health and Safety (Safety Signs and Signals) Regulations 1996 require appropriate safety signs where significant risks remain after other relevant controls have been taken.

BS EN ISO 7010 includes recognised graphical symbols for safety signs, including the W012 electrical hazard warning symbol.

However, there is no universal requirement for every plant room or switchgear area to display exactly the same combination of signs.

The appropriate signage depends on the installation, hazards and applicable requirements.

Do Electrical Warning Signs Make a Plant Room Compliant?

No.

Electrical warning signs should support suitable safety arrangements, including:

• Appropriate electrical installation and maintenance.

• Risk assessments.

• Safe isolation procedures.

• Access controls.

• Competent electrical work.

• Safe systems of work.

• Training and supervision.

Signs alone do not prevent contact with dangerous electrical equipment.

Common Mistakes When Buying Plant Room Electrical Signs

Avoid these frequent mistakes:

1. Assuming every switchgear room contains high-voltage equipment.

2. Using generic warnings where a more specific message is necessary.

3. Installing signs only inside a plant room.

4. Forgetting secondary entrances.

5. Choosing signs that are too small for the viewing distance.

6. Using unsuitable materials for the environment.

7. Relying on Authorised Personnel Only signs without physical access controls.

8. Allowing stored materials to obscure warnings.

9. Treating maintenance notices as a substitute for safe isolation.

10. Failing to review signage after electrical upgrades.

Plant Room & Switchgear Sign Buying Checklist

Use this checklist before placing an order.

Identify the Installation

• Electrical equipment identified.

• Operating voltages confirmed.

• Electrical hazards assessed.

• Access arrangements reviewed.

• Maintenance activities considered.

Choose the Signs

• Danger Electricity warnings considered.

• High Voltage signs selected where appropriate.

• Electric Shock or Danger of Death notices reviewed.

• Access restriction signs assessed.

• Keep Clear notices considered.

• Isolation and maintenance notices reviewed.

Select Products

• Sign sizes confirmed.

• Materials suitable for the environment.

• Mounting locations identified.

• Viewing distances checked.

• Quantities calculated.

Installation & Maintenance

• Signs visible before entering hazardous areas.

• All relevant entrances considered.

• Equipment-specific warnings checked.

• Damaged signs replaced.

• Signage reviewed after installation changes.

Frequently Asked Questions

What Electrical Hazard Signs Are Needed in a Plant Room?

The correct signs depend on the equipment and hazards present. They may include Danger Electricity, High Voltage, access restriction and maintenance notices.

Do Switchgear Rooms Need High Voltage Signs?

Only where the warning accurately reflects the installation. Many switchgear rooms contain low-voltage equipment.

What Is the Electrical Hazard Warning Symbol?

The recognised electrical hazard warning symbol is a black lightning bolt inside a yellow triangle, identified as W012 in BS EN ISO 7010.

Should Plant Rooms Have Authorised Personnel Only Signs?

Such signs may be appropriate where access restrictions are necessary. They should support suitable physical access controls.

Where Should Electrical Warning Signs Be Displayed?

They should be positioned where people can recognise the hazard before approaching or entering the relevant area.

Do Plant Rooms Need Keep Clear Signs?

Keep Clear notices may be useful where access to electrical equipment must remain unobstructed. The need depends on the installation and working arrangements.

What Size Electrical Hazard Sign Should I Buy?

Choose a size suitable for the viewing distance, mounting position, lighting and available space.

Can Electrical Hazard Signs Be Used Outdoors?

Selected products may be suitable for outdoor use where the material and fixing method are appropriate for the conditions.

Are Do Not Switch On Signs Suitable for Switchgear Maintenance?

They may be used as part of suitable maintenance arrangements, but a sign alone does not isolate electrical equipment.

Buy Electrical Hazard Signs for Plant Rooms from The Sign Shed

Whether you're fitting out a new plant room, updating switchgear warnings or replacing damaged notices across several buildings, choosing suitable electrical hazard signs helps communicate risks clearly.

At The Sign Shed, we supply a wide range of Electrical Hazard Signs for UK commercial buildings, factories, warehouses, hospitals, schools and industrial premises.

Our collection includes:

• Danger Electricity Signs.

• High Voltage Warning Signs.

• Danger of Death Signs.

• Electric Shock Risk Signs.

• Electrical Cupboard Signs.

• Electrical Isolation Notices.

Choose from a selection of sizes and materials to suit different applications.

Made in Britain, with automatic bulk savings available on eligible orders.

Shop Electrical Hazard Signs at The Sign Shed and find suitable warnings for your plant rooms and switchgear areas.