A POSC is a short, standardised inspection performed before a shift or before operating equipment to confirm that the refrigeration unit, container condition, plugs, leads and safety systems are serviceable and safe to operate. It reduces risk by ensuring that obvious defects (corroded plugs, damaged seals, loose wiring, alarm faults) are identified before a reefer is energised or moved, preventing electrical incidents, cargo loss and unsafe handling. POSC is mandatory in many terminals as part of the shipper/carrier PTI policy and broader CTU/IMO guidance because early detection of faults reduces claims and maintains cold-chain integrity. Reference
A concise POSC should verify container identity, visual condition (dents, floor, drains), door seals, interior cleanliness, correct setpoint and probe function, refrigeration unit power lead and plug condition, socket integrity, visible refrigerant/oil leaks, fan rotation and airflow, audible abnormal noises, and telemetry/alarm communication. The check must be recorded (time/operator) and any defect tagged for maintenance. This standardised list prevents common failures—particularly plug/cable faults and sensor errors—which are frequent root causes of cargo damage. Reference
A PTI is an in-depth inspection performed on an empty unit before stuffing or release and may take several hours; it includes functional testing of refrigeration machinery, refrigerant levels, and full operational proof. A POSC (shift-start check) is a short, frequent verification to confirm safe operation—visual checks, plug integrity, setpoint, probe reading and alarms. Terminals must use PTI for acceptance and POSC for routine safety; both are complementary: PTI validates long-term fitness, POSC prevents immediate operational hazards. Reference
POSC should be carried out by authorised and trained reefer technicians or terminal staff who understand electrical safety, basic refrigeration function, alarm interpretation and isolation procedures. Training must cover plug/socket inspection, LOTO basics, how to read controller alarms and when to escalate to maintenance or the container owner. Competency records and refresher training are industry best practices, reducing human errors that lead to unplugged reefers or unsafe connections. Insurers and P&I clubs emphasise formal competence for staff doing these checks. Reference
The POSC must include visual inspection for cracked insulation, bent/melted pins, corrosion, water ingress and secure locking collars. Operators should check that the correct plug type matches the socket, that the socket housing is undamaged, and that circuit breakers show no prior trips. Any suspect lead or socket must be tagged out and removed from service until tested. These checks prevent arcing, overheating and electrical faults that can cause fires or cargo loss. Reference
POSC should verify the controller displays (setpoint vs actual), listen for abnormal compressor or fan noises, confirm airflow through the T-floor or ducts, observe condenser cleanliness where accessible, check for refrigerant smell or oil, and validate telemetry reporting. A short run-up (if safe) to observe a single compressor cycle can reveal failures. Prompt identification of sensor faults or failing compressors allows corrective maintenance before a temperature excursion occurs. Reference
POSC records must capture container number, time/date, operator ID, checklist results, starting temperatures, any alarms seen, and corrective actions taken. Electronic logs tied to the TOS and telemetry are best because they create tamper-evident records and speed audits. Retained documentation of POSC and PTI supports claims defence by showing due diligence and that a unit was handed over in a known condition. P&I and insurers recommend keeping records for the product’s shelf-life and legal claim periods. Reference
Immediate isolation and lock-out/tag-out are required when POSC finds exposed live conductors, burning or melting at the plug, persistent electrical arcing, visible refrigerant/oil leakage posing hazards, or structural damage risking collapse. If a controller indicates catastrophic faults (lost control, severe compressor failure), the unit should be powered down and quarantined until certified safe. LOTO protects technicians and prevents accidental re-energisation during repair. Follow the site LOTO procedures and notify supervisors and the container owner. Reference
POSC should confirm that telemetry is active and reporting correct setpoint, supply and return temperatures, alarm codes, and power status. If telemetry fails or shows stale data, technicians must perform manual checks (probe readings, visual inspection) and escalate. Verifying telemetry at POSC ensures that shore-side monitoring will detect future excursions—otherwise hidden faults may go unnoticed until cargo damage occurs. Integrating telemetry checks into POSC is now a best practice. Reference
A POSC should be done at the start of every shift by operators who will be moving or monitoring reefers, and whenever a container is moved, plugged, or handed over. For high-risk cargo or after any maintenance, a POSC should be repeated. Frequency depends on terminal operations, but daily checks plus spot checks during peak activity are common to catch emergent faults quickly. Operator safety modules and terminal SOPs commonly mandate at-shift checks. Reference
POSC must include a quick interior check for cleanliness, odour, signs of pests or previous cargo taint, and that drains are clear. A contaminated or damp interior can compromise future loads and accelerate corrosion. If hygiene issues are identified, the unit should be quarantined for cleaning before stuffing. The CTU/IMO code and industry guidance require pre-stuffing sanitation as part of PTI, and POSC complements this requirement at operational handovers. Reference
POSC should visually inspect the door gasket condition, check that doors close and latch correctly, and confirm no visible deformation or damage to the frame that could allow air or water ingress. A simple check includes placing a folded paper strip in the seal to detect leaks or inspecting for bent hinges and floor defects. Compromised seals increase heat ingress and condensation risk and must be addressed before the unit is used for sensitive cargo. Reference
POSC is the day-to-day gatekeeper: if it reveals a recurring issue that PTI previously recorded as repaired, it should be escalated to engineering for root-cause analysis. POSC findings should feed maintenance schedules so that PTI and corrective work close the loop. Coordinated records between POSC and PTI prevent repeat failures and reduce downtime by ensuring that maintenance addresses operationally relevant faults. Reference
POSC for units using flammable (A2L) or high-pressure refrigerants (e.g., R-290, CO₂) must include checks for correct gas-type labelling, pressure-relief device condition, leak indicators and ATEX-rated plug integrity. Technicians need awareness of specific hazards and emergency steps (e.g., evacuation distances). POSC protocols should be updated, and staff retrained when new refrigerant technologies are introduced to ensure safety and compliance with local regulations. Guidance from manufacturers and regulators must be appended to POSC forms. Reference
Terminals should track POSC findings, classify defects, measure mean-time-to-repair, and feed the data back into training and procurement choices. Regular audits of POSC compliance, root-cause analysis of recurring faults, and KPI monitoring (e.g., per cent of POSC failures per 1,000 reefers) enable targeted interventions such as replacing unreliable leads, redesigning racks, or adjusting SOPs. Sharing anonymised incident data with carriers and manufacturers accelerates wider learning and improves industry standards. Reference
Reefer Runner is a fully wireless plug-and-play system that allows container terminals to track and manage refrigerated containers from end to end. It supplies continuous real-time readings — temperature, power state, energy use, alarms and performance — all visible within a TOS-integrated dashboard. This boosts operational visibility, cuts manual demands, reduces claim risks, enhances safety and maintains compliance.
Reefer Runner by Identec Solutions
Reefer containers commonly use three-phase 440-480 V power, and the sockets must be protected by adequately rated circuit breakers. According to ship classification rules, the ship must provide feeder circuits and breaker protection for all plug-in outlets to prevent overloads or short circuits. Reference
Interlocked connectors prevent “on-load” disconnection — power is only supplied when the plug is fully engaged and is automatically disconnected before the plug can be removed. This eliminates arcing risks, reducing the possibility of fire and shock during manual plug/unplug operations. Reference
Reefer plug systems typically conform to IEC 60309, an international standard for pin-and-sleeve industrial connectors. This standard ensures correct pin alignment, rated current capacity, IP protection, and compatibility across equipment. Reference
High-resistance connections—such as loose or corroded plugs and socket contacts—can generate excessive heat when carrying high current. This thermal build-up may reach thousands of degrees, potentially igniting surrounding materials and creating a serious fire hazard. Reference
Before powering up, operators should inspect cable insulation, check for cracks or corrosion in plugs, verify that sealing washers and glands are intact, ensure connections are tightened, and confirm socket housings remain watertight. This avoids loose or exposed conductors that may spark or short. Reference
Grounding ensures stray or fault currents have a safe path to earth, protecting personnel and electronics. If grounding is missing or degraded, there is a risk of electric shock or damage to sensitive refrigeration control systems. Proper grounding must be installed by qualified electricians and periodically verified. Reference
Because reefer compressors draw large inrush currents at start-up, using a breaker with incorrect characteristics can be dangerous. Undersized breakers will trip too often, while oversized ones may not interrupt fault currents quickly, risking fires or damage. The right choice (e.g., type C or D) ensures safe operation. Reference
Using Y-splitters or extension cords to increase reefer capacity risks overloading socket panels. Overloaded cords or sockets can overheat, garments may deteriorate, and fires may start. Proper load planning and avoiding overuse of splitters are essential. Reference
Cables and sockets should have high IP ratings (e.g., IP 67), corrosion-resistant materials, sealed gland connectors, and mechanical strain relief. These features protect against salt spray, moisture, and mechanical damage and ensure longevity in a terminal’s demanding environment. Reference
Properly coiling and securing power cables prevents them from swinging, snagging, or being cut when containers move. Safety-optimised solutions, such as automatic cable reels, avoid exposed hanging cables, reducing the risk of shock, trip hazards, or mechanical damage. Reference
Staff must understand the risks associated with high-voltage plugs, the importance of interlocks, how to verify connections, and what to do in case of a fault. Without this training, operators may unintentionally create dangerous conditions by connecting or disconnecting under load, leaving loose or corroded plugs in use, or ignoring insulation damage. Reference
Sealing washers prevent water ingress into plug housings. If they are missing or deteriorated, moisture can corrode contacts, raise resistance, and lead to overheating or arcing—particularly in marine or humid terminal environments. Regular inspection of these washers is critical. Reference
Overloading a socket can lead to excessive current draw, overheating of wiring or connectors, and potential fires. It can also stress upstream circuit breakers and damage terminal equipment. Electrical connections must always respect the rated capacity of plugs, sockets and distribution panels. Reference
To prevent shock risk or arc-flash, plugs should only be disconnected after the power is de-energised or locked out. Mechanical interlocks prevent the disconnecting live. In addition, personnel should use PPE, have appropriate LOTO procedures, and ensure that only trained staff perform the disconnect. Reference
A robust maintenance regime should include periodic inspection of sockets and plugs for wear or corrosion, testing of cable insulation, torque-checking connections, confirming interlock function, verifying grounding, and replacing any damaged components promptly. Documented inspections and corrective actions reduce the likelihood of failures that could cause shocks or fires. Reference
When reliable and effortless monitoring of refrigerated containers becomes a priority, an automated, one-dashboard approach is ideal. Reefer Runner delivers this through a simple, scalable system tailored for container terminals.
Reefer Runner by Identec Solutions
Reefer racks pose a heightened fire risk because of the electrical connections, high-current power leads, and potential overloading of sockets. Poorly maintained plugs or insulation failure can generate heat under load, while tight stacking and limited airflow may prevent heat dissipation. Once a module ignites, fire can spread rapidly through cable insulation and container walls. Also, faulty or corroded electrical connections contribute significantly to fire risk in stacked reefers. According to P&I and loss-prevention reports, many electrical fires in reefer units originate from connection points. Reference
Terminal design must ensure sufficient separation, ventilation paths, and safe access for fire response in reefer racks. Walk tunnels or ladder access allow safe inspection and emergency intervention. Structural rack design should incorporate fire-resistant materials, appropriate rack spacing, and cable management. Some rack designers provide safety tunnels or grating for personnel and fire suppression access, helping crews reach overheated modules quickly without risk of structural collapse. Reference
Power leads and connectors are the most common ignition points for reefer fires. Over time, insulation degrades, sealing washers corrode or are lost, and plugs loosen from vibration. These defects increase contact resistance, generate heat, and can ultimately ignite nearby materials. Recommended loss-prevention measures call for routine visual and thermal inspections to identify hot spots before they self-ignite. Reference
Proper grounding ensures that fault currents have a safe path to earth, reducing the risk of arcing and uncontrolled heating. Without effective grounding, even minor insulation damage can lead to dangerous fault currents that ignite insulation or nearby combustible materials. Ensuring every reefer socket and stack has a verified ground path is a foundational requirement in fire-safe electrical design for reefer racks. Reference
Overloading power circuits—especially through practices like using Y-splitters—can exceed the designed rating of sockets or cables, creating overheating and potential fire. To prevent this, load planning must avoid unsafely stacking or connecting reefers beyond circuit capacity, and terminals must restrict the use of multiple units on a single supply. Maintaining and adhering to rated power distribution prevents dangerous overloads. Reference
Early fire detection in reefer racks can rely on thermal surveillance (e.g., infrared cameras) or sensors that alert when a connection is overheating. Since reefers produce little visible smoke until significant damage, thermal monitoring or regular hot-spot scanning is more effective. Integration of these systems with terminal fire-alarm infrastructure allows safety teams to act quickly in response to abnormal temperatures before flame develops. Reference
Personnel must be trained to recognise pre-fire warning signs such as hot connectors, burnt insulation smell, or arcing. They should know how to safely disengage power, perform isolation, and initiate fire protocols. Training on proper cable routing, correct plug seating, and maintenance routines helps staff prevent conditions that commonly lead to fire. According to guidelines, human error plays a major role, so frequent training and refresher courses are vital. Reference
Effective preventive maintenance includes torque-checking plug collars, verifying sealing washers, inspecting for insulation degradation, testing grounding continuity, replacing aged leads, and cleaning socket housings. Thermographic (IR) inspections can detect overheating connections. Documented schedules and corrective action plans must be in place to address any defects before they evolve into ignition sources. Reference
Terminals should equip reefer racks with accessible fire-fighting provisions, such as boundary cooling, fire suppression agents (e.g., water or CO₂), and fire detection linked to central alarm panels. Emergency procedures must include safe isolation of power and safe access pathways (e.g., walk-through tunnels). Terminals must also coordinate with port or shipboard fire teams and define clear fire-fighting zones. Reference
Proper ventilation helps dissipate heat from plugs, leads, and container surfaces, preventing local hotspots from building up. Without airflow, overheating connections may reach ignition temperature more easily. Terminal rack designs should therefore include adequate ventilation gaps and avoid tightly packed stacks without airflow paths. Reference
Stacks that are too tall raise the risk of fire escalation because it becomes more difficult to detect or access hot connections at higher tiers. High stacks also complicate firefighting (access for personnel, water or suppression agents). Limitations on stack height and mandatory safe access (e.g., platforms, ladders) help mitigate the risk of uncontrolled fire spread. Reference
Risk assessments must evaluate electrical load profiles, circuit capacity, predicted peak draw, insulation age, connector condition, and stack configuration. Safety teams should simulate fault conditions (e.g., connector heating, overload) and model worst-case fire scenarios. These assessments should guide maintenance frequency, monitoring strategies, and rack design improvements. The IIMS loss-prevention guidance recommends such structured risk planning. Reference
Poor yard operations—such as incorrectly plugging reefers, using Y-splitters, or handling damaged cables—can significantly elevate fire risk. Additionally, stacking reefers without considering power-circuit capacity or failing to rotate or inspect connected reefers can lead to hotspots. A strong safety culture, SOPs for stacking, and strict enforcement of power connection rules are essential to prevent ignition sources. Reference
Emerging fire-suppression technologies like the HydroPen system (which allows firefighting inside a container via “drill-and-spray”) can help contain fires within reefers before they spread to adjacent units. Early detection combined with rapid deployment of suppression tools enhances safety in dense stacks. According to fire-safety news, such systems are gaining traction in container-stack fire prevention. Reference
Terminals should design reefer blocks with buffer zones or fire-break lanes that limit fire spread, as well as ensure that high-risk reefers (e.g., older units, high power draw) are not all clustered together. Strategic planning can enforce separation and allow safe fire-fighting access. Combining this with robust surveillance helps detect and mitigate fire-prone conditions early. Reference
Purpose-built to integrate with your terminal’s wider IT framework, Reefer Runner soon becomes operationally indispensable. The system is as simple as it gets: no training needed, plug-and-play with the TOS, quick installation and scalable design.
Reefer Runner by Identec Solutions
Disconnecting a reefer plug under load can cause arcing, which may damage contacts, generate heat, or ignite debris. Safe design practices require that the circuit be de-energised before removing the plug. According to international container-stowage guidance, the interlock mechanism should break the circuit during removal so that live parts remain disconnected before the plug is withdrawn. Reference
Workers should wear insulated gloves, safety glasses or a face shield, and arc-flash rated clothing when handling reefer connections. Electrical safety guidance from international labour organisations stipulates that properly trained staff should use insulated protective gear to reduce the risk of electric shock or arc-flash during plug/unplug operations. Reference
An interlock prevents the socket from being live unless the plug is fully seated. When the plug is pulled, the interlock cuts power before disconnection, greatly reducing the risk of arcs or sparks. ESL Power recommends using designs that detect the ground pin before energising, ensuring safe engagement. Reference
First, inspect the plug, cable, and socket for damage or moisture. Confirm power is isolated. Align the plug properly, fully engage it, then lock the collar. Only then, energise the circuit and verify power-up (controller, telemetry, alarms). This sequence ensures a safe, secure, and trusted electrical connection. Reference
To unplug, first power down or isolate the circuit, unlock the collar, and then withdraw the plug carefully. Never pull the plug out by the cord. If the connection is tight, twist gently to avoid damaging contacts. Following the correct procedure prevents arcing and prolongs the life of the plug/socket system. Reference
Loose or poorly coiled power cables dangling around container stacks can be damaged by handling equipment, lifting operations, or environmental exposure. Damage to the cable insulation or plug can lead to electrical faults, shocks, or fire. Guidelines from risk assessments stress the importance of proper cable management before and after use. Reference
Before every plug-in, inspect for worn or cracked insulation, melting or discolouration of plug housing/pins, corrosion, water ingress, and tightness of locking collar. These checks help catch early signs of faulty connections that could lead to overheating or electrical failure. Reference
If the supply voltage or phase does not match the reefer’s rated requirements, do not force the connection. Engage a qualified electrician to provide the correct circuit or transformer. Mismatched voltage or phase can cause motor stress, electrical damage, or overheating. Reference
Terminals should audit plug-in/out procedures monthly or quarterly, depending on volume. Audits should check worker compliance with procedures, proper use of PPE, record-keeping, and equipment condition. Frequent audits help identify unsafe habits early and reinforce safety culture. Reference
Because handling high-voltage reefer connections involves risk of shock, arcing, fire, or damage, staff must be trained in correct procedures, the function of interlocks, safe de-energisation, and personal protection. Well-trained personnel reduce risk and contribute to terminal safety, as highlighted in international electrical-safety guidelines. Reference
If the controller does not show correct readings, or alarms, or if there is no power, immediately isolate the circuit. Do not reenergize until a qualified technician has inspected the plug, socket, and power source. Faulty connections or wiring may be at fault and must be addressed before reuse. Reference
After restow, always verify that the plug is secure, then isolate power before unplugging. Because movement can strain or loosen the connection, additional care is required. Such checks ensure no arc occurs and prevent cable and connector damage. Reference
Clear communication ensures that power is not switched on or off unexpectedly, and that staff know when a plug is engaged or scheduled for removal. This coordination prevents energising during mechanical operations or when people are handling the plug, reducing the risk of shock or damage. Reference
If sparks, smoke or arcing are seen, isolate the circuit immediately, notify electrical safety personnel, and evacuate the area if needed. Use lock-out/tag-out to prevent re-energisation, and follow fire-prevention protocols. Document the incident and use it in safety debriefs to prevent recurrence. Reference
Terminals should log plug-in/out events, noting container ID, socket ID, time, operator, and any anomalies (e.g., resistance, heat, visible damage). These records help trace recurring issues and demonstrate compliance with safety audits and insurers. Reference
Get a live, accurate picture of each reefer container in your yard, whatever its make or specification. Implement a wireless network that links every reefer data port to one central system and ensures complete, compliant documentation.
Reefer Runner by Identec Solutions
Technology & Equipment: Reefer Container Types | Refrigeration and Airflow Systems | Power Supply and Electrical Systems | Energy Efficiency and Power Optimisation | Sensors, Controls, and IoT Integration | Monitoring and Automation Systems | Maintenance, Lifecycle, and Reliability | Standards, Compliance, and Certification
Transport & Modalities: Overview of Refrigerated Transport | Reefer Vessels and Maritime Operations | Stowage | Intermodal and Inland Reefer Transport | Trade Routes and Global Flows | Cold Corridor and Regional Infrastructure | Reefer Flow Management and Balancing |
Chronology & Operations: Chronology of the Cold Chain | Initial Cargo Conditioning | Pre-Cooling | Staging, Storage, and Cold Integrity | Reefer Handling at Terminals | Empty Reefer and Return Operations | Reefer Maintenance and Technical Inspections |
Monitoring, Data & KPIs: Reefer Monitoring Systems and Infrastructure | Parameters and Data Collection | Alarm Management and Response | Data Management and Analytics | Performance and KPI Measurement |
Cargo & Commodity Handling: Cargo Categories and Industry Applications | Cargo Preparation and Pre-Loading | Packaging and Protection Technologies | Dangerous and Sensitive Goods Handling | Quality Assurance and Traceability |
Sustainability & Environmental Impact: Energy Efficiency and Power Optimisation | Carbon Footprint and Emission Tracking | Packaging and Waste Reduction | Infrastructure Efficiency and Green Design |
Safety: Operational and Equipment Safety | Cargo Handling and Physical Safety | Chemical and Refrigerant Safety | Personnel and Procedural Safety | Training and Continuous Improvement |