Terminal lighting must be grounded when it concerns Class I luminaires, metal housings, or installations in wet, corrosive, or explosion-hazard environments. This applies in virtually all professional terminal environments. Grounding is not optional: it is a legal requirement and a direct safety measure that prevents dangerous voltage differences. In this article, we answer the most frequently asked questions about grounding terminal lighting, from risks and standards to execution and inspection frequency.

What are the risks if terminal lighting is not grounded?

A wiring or fixture defect combined with a missing earth connection can lead to hazardous touch voltages on metal parts. This poses a direct risk of electric shock to employees. In wet or damp environments, such as terminals and quays, this risk increases significantly — and fire or equipment damage caused by electric arcs is also a looming threat.

Terminals are environments with a lot of moving equipment, vibrations, and severe weather conditions. A damaged connection cable or a loose cable gland can already be enough to energize a luminaire. Without grounding, that voltage has nowhere to go except through a person touching the pole or the luminaire.

In addition to the direct danger to individuals, there are also operational risks to consider:

• Lighting failure due to damaged components after an earth fault
• Damage to adjacent electrical systems caused by electric arcs
• Liability in the event of incidents when grounding is demonstrably absent
• Failed inspections or audits

Which standards and regulations determine the mandatory grounding requirement?

The basis is provided by NEN 1010: the Dutch standard for low-voltage installations, which prescribes when and how protective earthing must be applied. Additionally, for maritime and port environments, the NEN-EN 60079 series applies for explosive atmospheres and the IEC 60364 series for electrical installations in special environments.

For terminals and ports, the requirements from the Working Conditions Act are also relevant. The employer is obligated to guarantee a safe working environment, which has direct consequences for the electrical installations on the site. Inspections by a recognized inspection body, such as a NEN 3140 inspection, verify, among other things, whether all lighting is properly grounded.

By marine lighting specific requirements from classification societies such as Lloyd's Register or Bureau Veritas also apply, depending on the location and type of installation. These bodies enforce strict requirements for the earthing of all electrical systems on board and onshore.

Which types of terminal lighting must always be earthed?

In short: all Class I luminaires. These are luminaires where protection against electric shock relies on the earth connection. In practice, this applies to virtually all metal luminaires at terminals, including LED floodlights work lights on masts, working lights on cranes, and lighting in loading and unloading areas.

The following types of terminal lighting always require proper grounding:

• LED floodlights with metal housing on light poles and gantry structures
• Crane and harbour crane lighting on conductive structures
• Valves in potentially explosive ATEX zones
• Lighting in wet or damp areas (IP65 or higher)
• Luminaires on steel poles or structures with conductive contact

Class II luminaires (double insulation) technically do not need to be earthed, but for this type as well, the mounting structure itself may need to be earthed. In practice, almost exclusively class I luminaires are used at terminals due to the harsh environmental requirements. More information about suitable luminaires can be found on the page about Harbors and terminals lighting.

How is the earthing of terminal lighting correctly carried out?

Proper grounding consists of a continuous connection from the luminaire through the installation to the earthing point of the supplying distribution board. Every link in that chain must be electrically reliable and meet the required cross-section for the earth conductor.

Correct execution proceeds step by step:

1. Determine the earth conductor cross-section based on the phase conductor and the short-circuit current. This is specified in NEN 1010, Table 54.2.
2. Connect the fixture via a green or yellow-green earth conductor to the earth terminal in the junction box.
3. Ensure continuity by running the earth conductor continuously through cable glands, cable trays and distribution boards.
4. Earth the mast or structure on which the luminaire is mounted, separately to the main earthing terminal of the installation.
5. Measure the earth resistance after installation and document the values for the inspection.
6. Have the installation inspected by a certified electrical installer in accordance with NEN 3140.

For installations in corrosive environments, such as dock areas with marine air, the use of stainless steel cable glands and earth clamps is strongly recommended. Standard galvanized connections can corrode within a few years to such an extent that the earth connection loses its function.

When is grounding especially critical for terminal lighting?

There are situations where the probability of an earth fault is higher, or where the consequences of an incident are more severe. On terminals, these are the zones where water, corrosion, vibrations, or explosion hazards coincide with electrical installations.

Specific situations where extra attention to grounding is required:

• Quay areas and loading platforms where salty air damages insulation and connections
• ATEX zones around tank storage, fueling points or chemical plants
• Crane lighting on electrically driven gantry cranes and port cranes, where vibrations shake cable connections loose
• Temporary lighting installations during construction or expansion projects on the site
• Installations after renovation or expansion, whereby new luminaires are connected to existing earth loops

Especially with lighting for extreme corrosion is the earthing connection a point of concern, because corrosion can interrupt the electrical continuity of the earth conductor without this being immediately visible.

How often must the grounding of terminal lighting be checked?

At least every three years, the grounding must be checked as part of the periodic electrical inspection in accordance with NEN 3140. In environments with increased wear and tear, such as quay areas with marine air or heavy-use zones, an annual visual inspection and a biennial measurement are recommended.

During an inspection, the following aspects are evaluated:

• Visual condition of earth conductors, terminals, and cable glands
• Measurement of the earth conductor and earth resistance
• Continuity of the earth connection from the luminaire to the main earthing terminal
• Condition of corrosion-prone joints in outdoor installations

In addition to periodic inspections, it is advisable to check the grounding immediately after any incident—such as a pole collision, storm damage, or an electrical malfunction. Furthermore, after replacing luminaires or making modifications to the installation, the grounding must be verified before the installation is put back into service.

Stricter inspection requirements apply to installations in ATEX zones. NEN-EN 60079-17 prescribes that electrical installations in hazardous areas must be regularly inspected, with earthing being a mandatory part of the inspection routine. Always consult a certified inspection body with demonstrable experience in explosion safety for this purpose.

Examples from practice: DFDS Terminal Lighting

A clear example of how grounding and material selection come together in practice is the project carried out for DFDS — a major player in ro-ro terminal logistics. The challenges were multifaceted: the terminal operates day and night, which meant that the installation of fixtures had to take place without a complete shutdown. Furthermore, the location is situated directly on the water, with constant exposure to salty sea air — one of the most aggressively corrosive environments for electrical installations.

The chosen luminaires had to meet high IP ratings and are equipped with stainless steel fasteners and cable glands, exactly as recommended for quayside areas. Crucially, the earth connections were already included in the design during the engineering phase, so that each luminaire on the steel structures could be correctly connected to the main earthing point. This prevented expensive adjustments afterwards and ensured an inspection without any comments.

The lesson learned from this project is directly applicable to the subject of this article: grounding must not be an afterthought. By integrating grounding as early as the design phase—including the right choice of materials for corrosive environments—you prevent costly corrections after completion and ensure long-term safety. More projects like this can be viewed at DFDS Seaways Vlaardingen Project Page.

How JEL Products Helps with Grounding and Terminal Lighting

JEL Products not only supplies high-quality LED fixtures for terminals and ports, but also provides support throughout the entire process of implementing lighting solutions in demanding environments. This always includes attention to technical requirements, such as grounding, IP rating, and material selection for corrosive environments.

Specifically, JEL Products offers:

• Fixtures with certified housings, suitable for Class I installations in wet and corrosive environments
• ATEX-certified lighting solutions for hazardous areas at terminals
• Stainless steel versions for dock areas subject to extreme corrosion
• Complete lighting design including technical specifications for the electrical installation
• Guidance from engineering to commissioning, ensuring that earthing and inspection are correctly guaranteed

Whether it concerns lighting for harbor cranes, area lighting, or specialized custom solutions, the full technical context is always considered, including earthing and material selection. Feel free to contact us via the contact page for a no-obligation discussion about your situation.

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