Electrical contracting for an oil and gas facility involves the same core scope as any industrial project, which is design, supply, installation, testing and maintenance of power systems, but with stricter rules for hazardous areas, higher demands for reliability and much heavier documentation. A refinery, terminal or processing plant cannot afford an ignition source in the wrong place or an unplanned power loss, so the electrical contractor works to operator specifications, certified equipment and formal quality records at every step. This guide from Paklink LLC explains what changes in oil and gas, from hazardous area classification and certified equipment to switchgear, cabling, earthing, documentation and commissioning. If you are new to the wider subject, start with our full guide to industrial electrical contractors in Dubai.
In short:
- Hazardous areas set the rules: equipment must be certified for the zone, gas group and temperature class where it is installed.
- Reliability is designed in through redundant supplies, robust switchgear and protection that isolates faults without losing the plant.
- Documentation is part of the deliverable. Certificates, test records and equipment registers must be complete and traceable.
- Competent people and strict permit systems matter as much as the equipment.
What makes oil and gas electrical work different?
The difference is consequence. A fault in an office building causes inconvenience, but a fault or spark in a plant handling flammable gas or liquid can cause a fire or explosion, and a power loss can force a costly and unsafe shutdown. Four features set oil and gas apart:
| Feature | What it means in practice |
|---|---|
| Hazardous areas | Large parts of the site may contain flammable gas or vapor, so equipment must be explosion-protected and certified |
| Reliability | Supply arrangements are often redundant, with standby sources and protection designed to keep critical loads running |
| Specifications | Operators set detailed technical standards that often go beyond national codes |
| Documentation and quality | Every piece of equipment and every test is recorded, traceable and reviewed |
Compared with a typical commercial or general industrial project, the same switchgear, motor control centers and cabling are present, but the choices, checks and paperwork around them are more demanding.
What are hazardous areas, and how are they classified?
A hazardous area is a location where an explosive atmosphere may be present, and it is classified into zones according to how likely and how long that atmosphere is to exist. Classification is the starting point for all electrical design in these areas, because it decides which equipment is allowed.
For gas and vapor, the zones are:
| Zone | Likelihood of an explosive gas atmosphere |
|---|---|
| Zone 0 | Present continuously or for long periods |
| Zone 1 | Likely to occur in normal operation |
| Zone 2 | Not likely in normal operation, and if it occurs it lasts only a short time |
Dust areas use Zones 20, 21 and 22 with the same logic. The classification is prepared by qualified specialists, shown on hazardous area drawings and recorded in an equipment register. The contractor does not choose it, but must install exactly what the classification requires.
Three further ratings complete the picture:
- Gas group (IIA, IIB, IIC): how easily the gas ignites, with IIC the most demanding.
- Temperature class (T1 to T6): the maximum surface temperature equipment may reach, which must stay below the ignition temperature of the gas.
- Equipment protection level (Ga, Gb, Gc): the level of protection the equipment provides, matched to the zone.
An illustrative example of temperature class: if a gas ignites at 280°C, equipment must have a maximum surface temperature below that. The temperature classes set maxima of 450°C (T1), 300°C (T2), 200°C (T3), 135°C (T4), 100°C (T5) and 85°C (T6). T3 or a lower class would be acceptable here, while T2 would not, since its 300°C limit exceeds the ignition point. Always take the actual figures from the hazardous area classification and the equipment certificate.
Which standards and certifications apply?
The IEC 60079 series is the main international framework for equipment and installations in explosive atmospheres. Parts relevant to the contractor include:
| Standard | What it covers |
|---|---|
| IEC 60079-0 | General requirements for explosion-protected equipment |
| IEC 60079-10-1 | Classification of explosive gas atmospheres |
| IEC 60079-14 | Design, selection and erection of electrical installations |
| IEC 60079-17 | Inspection and maintenance of electrical installations |
| IEC 60079-19 | Repair, overhaul and reclamation of equipment |
You can browse the IEC family on the IEC website. Equipment is normally proven through a certification scheme. IECEx is the international scheme, and you can find out more at IECEx. ATEX is the European framework, and it is often named in specifications in the region. Check which schemes the operator accepts, because the specification decides, not general practice.
Beyond these, operators issue their own standards and data requirements, and contractors are typically assessed on safety record, quality management and competence before they are allowed to bid.
How is explosion-protected equipment built?
Explosion protection works by preventing ignition or containing it, and each method suits different equipment and zones. The common protection types are:
| Type | Marking | How it works | Typical use |
|---|---|---|---|
| Flameproof | Ex d | The enclosure withstands an internal explosion and stops it spreading | Motors, switches, junction boxes, lighting |
| Increased safety | Ex e | Extra measures prevent arcs, sparks and hot surfaces | Terminal boxes, motors, lighting |
| Intrinsic safety | Ex i | Energy in the circuit is limited too low to ignite gas | Instruments and sensors, including Zone 0 |
| Pressurized | Ex p | The enclosure is kept at a pressure that keeps gas out | Large panels and machines |
| Encapsulation | Ex m | Components are sealed in a compound | Small electronic parts |
Markings on the equipment show the protection type, gas group, temperature class and protection level. Learning to read them is a core skill on site, because installing equipment with the wrong marking is a safety failure, not a paperwork issue.
What switchgear and MCC specifications do these sites ask for?
Oil and gas sites usually specify robust, high-separation switchgear and well-documented motor control centers. The typical requirements are:
- High internal separation, such as Form 4 Type 7 construction in low voltage assemblies, so one compartment can be worked on while others stay live.
- Type-tested assemblies with verification evidence, built to IEC 61439 for low voltage and IEC 62271 for medium voltage.
- Arc fault protection, with internal arc classification where operators enter the switch room.
- Withdrawable construction for motor control centers, so failed starters can be swapped quickly.
- Intelligent motor control with communication to the plant control system, for monitoring and diagnostics.
- Design for the environment, including heat, dust and corrosive air, with proper room air conditioning.
Switchgear usually sits in a controlled, non-hazardous electrical room, so the main hazardous area attention goes to field equipment, cables and instruments. The power system itself is often supplied from package substations. Equipment details should always be read against the project specification.
How is power supply reliability built in?
Reliability comes from how the system is arranged, not only from how good each piece of equipment is. Common features include:
- Dual incoming supplies with a bus coupler and automatic changeover, so one failure does not take out the switchboard.
- Redundant transformers, often sized so one can carry the load if the other is out.
- Standby generators that start on loss of mains and feed essential loads.
- UPS and DC systems for control, protection and safety systems that must never lose power.
- A power management system that shares load, sheds non-essential loads and coordinates generators during disturbances.
- Protection coordination, so a fault trips the nearest device and the rest of the plant keeps running.
The contractor’s role is to build, test and prove these arrangements. Automatic changeover, load shedding and generator starting are all tested as part of commissioning, because they only matter if they work when needed.
How are cables, glands and containment chosen?
Cable choice in oil and gas weighs mechanical protection, fire performance and the hazardous area rules together. Typical requirements are:
| Item | Typical requirement |
|---|---|
| Power and control cables | Armored cable for mechanical protection, often flame-retardant and low smoke and halogen free in enclosed areas |
| Fire-resistant circuits | Cables that keep working during a fire for safety systems, selected to the relevant fire test standards |
| Cable glands | Certified for the protection type and area, installed and sealed correctly |
| Instrument cables | Segregated from power, with screening, and kept separate for intrinsically safe circuits |
| Containment | Material chosen for corrosion, such as galvanized or stainless steel, or GRP in aggressive environments |
Cable glands deserve particular attention. A wrong or badly fitted gland can undo the protection of an otherwise certified enclosure, which is why gland installation is normally inspected as a separate item. For help comparing containment choices, see our guide to cable trays vs conduits, which covers materials, supports and fire barriers.
How does process heating fit into oil and gas projects?
Many oil and gas processes need heat tracing, because viscous products, waxy fluids and chemicals must stay at a set temperature to keep flowing. In hazardous areas, heating cables and their terminations must be certified, and the surface temperature must stay below the ignition temperature of the gas. High-temperature process lines often use mineral insulated cable, which suits harsh conditions. Our guide to heat tracing and process heating in electrical projects explains how to size the supply, protect the circuits and control them.
What do earthing, lightning and static protection involve?
Earthing and bonding in oil and gas do more than protect against shock, because they also prevent static sparks. The main elements are:
- A low-resistance earthing system designed for the site’s fault currents and soil conditions.
- Equipotential bonding of pipework, vessels, structures and cable supports, so no dangerous potential differences exist.
- Static control through bonding of flanges, loading equipment and movable parts where static can build up.
- Lightning protection, usually designed to the IEC 62305 series, with surge protection on power and signal circuits.
- Clean earth arrangements for instruments and intrinsically safe circuits, as the design requires.
Earth testing is repeated at commissioning and at intervals afterwards, and the results go into the site records.
What documentation and quality records are required?
Documentation is a deliverable, and often the thing that decides whether work is accepted. A typical package includes:
- Hazardous area classification drawings and equipment schedules
- Certificates for explosion-protected equipment, with traceability to each installed item
- Inspection and test plans agreed before work starts
- Material certificates and traceability records
- Test and inspection records, including cable and earthing tests
- Calibration records for test instruments
- As-built drawings, cable schedules and loop diagrams
- Operation and maintenance manuals and spare parts lists
- Punch lists showing open items and how they were closed
Good contractors build this record as they go, not at the end. Missing certificates and untraceable equipment cause far more delays at handover than technical faults do.
How do testing, commissioning and handover differ?
The stages are the same as any project, but they are more formal and more heavily witnessed. A typical sequence runs as follows:
- Factory acceptance tests (FAT). Key equipment such as switchgear and panels is tested at the manufacturer, often with the client present.
- Installation inspection. Equipment, glands, cables and earthing are checked against the classification and the specification, including an initial inspection of hazardous area installations.
- Pre-commissioning checks. Insulation, continuity and earth tests, protection relay tests and instrument loop checks.
- Site acceptance tests (SAT) and functional tests. Interlocks, changeover schemes, alarms and control sequences are proven.
- Mechanical completion and punch list. Open items are listed, closed and signed off.
- Energization and commissioning. The supply is switched on in a controlled sequence under permits.
- Handover. The documentation package and training are delivered, and the client accepts the system.
What safety practices apply on site?
Safety systems are formal and strict, and they apply to every person on site. The main ones are:
- Permit-to-work for all hazardous jobs, stating scope, hazards and controls.
- Hot work permits for any task that could create a spark or flame, with gas testing before work starts.
- Lockout and tagout to isolate and prove equipment dead before work.
- Competence. Staff working on explosion-protected equipment are expected to hold recognized competence, for example under schemes such as CompEx, and to be trained for the site.
- Site induction and toolbox talks, repeated as the work changes.
- Confined space and working at height controls where they apply.
Operators look closely at a contractor’s safety record when they prequalify bidders, so safety performance directly affects the work a contractor can win.
How do you maintain electrical equipment in hazardous areas?
Maintenance keeps equipment safe, and it must not undo the protection built into it. IEC 60079-17 describes inspection regimes with initial, periodic and sample inspections, and IEC 60079-19 covers repair and overhaul. Good practice includes:
- Keeping an up-to-date equipment register that links each item to its certificate and location
- Inspecting enclosures, glands, seals and earthing at planned intervals
- Using certified repair facilities and original parts for explosion-protected equipment
- Controlling modifications, because an unauthorized change can void certification
- Using thermal imaging and electrical testing to find loose connections and hot spots, where safe to do so under permit
A general preventive maintenance program applies here too, and the hazardous area rules add certification and record requirements on top.
What mistakes do oil and gas electrical projects commonly make?
Most problems come from process and paperwork, not from the technology. Six mistakes appear repeatedly:
- Installing equipment that does not match the classification, such as the wrong temperature class or gas group
- Poorly fitted cable glands, which undo the protection of the enclosure
- Missing or untraceable certificates, which stall handover
- Late design changes, which break the match between the drawings, the equipment and the records
- Untested changeover and load shedding, so reliability features fail when needed
- Underestimating documentation, and trying to build the dossier after the work is done
Planning an electrical scope for an oil and gas facility?
If you are preparing a tender, reviewing a specification or looking for a contractor team that understands hazardous area work, talk to the team at Paklink LLC about your site, standards and programmed. You can also read about our oil and gas electrical contracting in Dubai.
Frequently asked questions
What is a hazardous area in oil and gas?
It is a location where flammable gas, vapor or dust may be present in amounts that could cause an explosion, so electrical equipment must be explosion-protected and certified for the zone.
What do Zone 0, Zone 1 and Zone 2 mean?
They describe how likely an explosive gas atmosphere is. Zone 0 is present continuously or for long periods, Zone 1 is likely in normal operation, and Zone 2 is not likely in normal operation and short-lived if it occurs.
What is the difference between IECEx and ATEX?
IECEx is an international certification scheme for equipment in explosive atmospheres. ATEX is the European framework. Specifications name the scheme they accept, so check the project requirements.
What does Ex d mean on equipment?
Ex d means flameproof protection. The enclosure can withstand an internal explosion and stop it from igniting the atmosphere outside.
Why is Form 4 Type 7 switchgear common in oil and gas?
It gives a very high level of internal separation, so one compartment can be maintained while others stay live. That reduces downtime and improves safety in plants that cannot easily shut down.
What documents does an oil and gas electrical contractor have to provide?
Typically equipment certificates, inspection and test records, material traceability, calibration records, as-built drawings, cable schedules, manuals and punch list closure.
Who classifies hazardous areas? Qualified specialists prepare the classification as part of the design. The electrical contractor installs equipment to match it, and does not set the classification.
