Well, you’ve finally set up the PLC. The commissioning is done after a grueling 8-hour shift. Tomorrow, you think you’re just going to touch up the system. After 3 weeks, you get a call from the site: “Machine’s down, get here now!”

You only now realise — you’ve been called to commission other systems before implementing any documentation, comments, or testing edge cases.

You’re always going to be under pressure when designing and implementing PLC systems, especially during breakdowns. The company is losing thousands of rands per hour due to downtime. They need, and I mean it, need you to solve this NOW!

This typically leads to you building PLC systems that are “good enough” — they just need to work now. After the problem is solved, it’s solved.

Unfortunately, this leads to slip-ups, bugs, unmaintainable architecture, and most importantly, wasted time that could have been spent designing and implementing better features or systems. Now you’re stuck maintaining code that you can’t read, that doesn’t make sense, and often represents a cobbled-together system — not the actual representation of how the system works.

Factors Affecting Maintenance Costs

According to a 2020 study on software maintenance cost factors, maintenance activities account for a significant portion of software lifecycle effort and cost.

The main technical factors that affect the cost are:

• Software Complexity: The need to understand and extend software. In the case of PLCs, the harder it is to read and understand the code, the harder it is to extend and fix bugs. This adds costs.
• Developed Human Capacity: The expertise of a specific engineer, their experience in having solved multiple problems, and their understanding of the problem domain make it easier to maintain systems. In PLCs, competent engineers can more quickly perform troubleshooting and resolve use cases. This makes placing unskilled engineers in more difficult projects take longer to maintain, adding costs.
• Document Quality: Outlining system and maintenance documentation allows maintainers and extenders to easily add or fix bugs, reducing costs. In PLCs, a lack of documentation adds to software complexity and the need to understand the system from first principles, leading to engineers taking longer to troubleshoot the system and to fix the intended bugs, adding maintenance costs.
• Modern Programming Specifications: Good programming practices that aim at building modular systems, correct naming conventions, and documentation all affect the maintenance cost. Often in PLC systems, the system was written 5+ years ago. A lack of documentation, best practices, and creating coupled (dependent) components and subsystems make it harder to understand, extend, and troubleshoot – increasing costs.

Building Maintainable PLC Systems

To build maintainable PLC systems, you should aim to:

• Use clear and consistent naming conventions: Inputs, outputs, alarms, timers, and internal states should be named predictably and descriptively. This makes troubleshooting significantly easier during downtime situations.
• Keep logic modular and structured: Group related functionality together and avoid tightly coupling unrelated systems. A conveyor fault should not unexpectedly affect unrelated machine states.
• Document changes properly: Electrical drawings, PLC backups, I/O lists, and network configurations should always reflect the actual running system. Outdated documentation can make troubleshooting far more difficult than the fault itself.
• Write logic that reflects the physical process: PLC code should mirror how the machine actually operates. Engineers and technicians should be able to follow the sequence of operation logically.
• Avoid “temporary” fixes becoming permanent: Quick fixes made during breakdowns should later be reviewed and properly integrated into the system architecture.
• Implement diagnostics and alarming properly: Good fault messages and diagnostic bits reduce troubleshooting time and make failures easier to isolate.
• Test edge cases before deployment: Systems should not only work under ideal conditions, but also during sensor faults, communication loss, startup conditions, and unexpected operator actions.

Summary

Maintainable PLC systems are not built by accident. They come from engineers taking the time to structure logic properly, document systems, follow consistent standards, and think beyond just getting the machine running.

During breakdowns and commissioning, there will always be pressure to implement quick fixes and “good enough” solutions. Unfortunately, those shortcuts often become long-term maintenance problems that cost far more time and money later on.

A maintainable PLC system should not only work today, but it should still be understandable, extendable, and troubleshootable years later by another engineer standing on site during downtime.

The post Designing a Maintainable PLC System appeared first on Control Hub.

Programmable Logic Controllers (PLCs) are designed and manufactured to sustain constant operations in harsh industrial environments, making them rugged computing devices for a whole host of applications. From control systems on the International Space Station to safety devices on naval ships.

PLCs allow us to control and automate low-level operations by sending rudimentary signals as needed to activate sensors, read data, or simply record data in databases. This ensures reliable and consistent control output.

No rugged machine lasts forever, though; machines will tend to fail over time. A clock’s cogs are starting to rust, worn-out gaskets in the air compressor, and electronics are failing due to electromagnetic interference.

Why Should You Care?

PLCs are primarily deployed in mission-critical, predictable control systems.

Factories generate profits from producing goods on a factory line; stopping that line could mean the difference between a loss of thousands to millions of rands.

On mission-critical systems, such as nuclear power plants that were commissioned in the 90’s in the US, PLCs enable predictable control of safety systems. A PLC failure in a nuclear power plant could mean overheating of the cooling system, a lack of pressure regulation in the reactor core, or a failure of an emergency shutdown to trigger. Consequences that could level a city and cause mass fatalities.

In most software disciplines, a slip-up could just mean the user isn’t happy with a graphical glitch. In PLCs, a failure could mean a loss of human life, thousands of rands of profit down the drain.

Signs of Failure

Immediate Signs: LEDs

PLC manufacturers flash their hardware to show red lights on CPUs, communication cards, fuse blocks, and I/O cards. If you see a red light on any of these hardware components, you could be facing general issues with the hardware itself.

It is also advisable to inspect Ethernet ports and communication interfaces for link and activity lights. A lack of communication lights could indicate damaged cabling, failed communication cards, switch failures, or incorrect network configuration.

Some PLCs may also display fault indicators directly on the CPU itself. Intermittent fault lights or faults that temporarily disappear after cycling power can potentially indicate degrading hardware, unstable power supplies, or communication issues.

Burning smells, excessive heat inside the cabinet, or visible discoloration around terminals and connectors can also indicate failing electrical components or damaged hardware.

• Fuse blocks: Check if the fuse was blown and retry the setup. It was just the fuse, and the machine should start up again.
• I/O cards: Inputs changing state without outputs reacting correctly can indicate faults with output cards, field wiring, or PLC logic.
• Analog modules: Incorrect analog readings that do not match field measurements can indicate sensor faults, scaling issues, wiring faults, or analog input card failures.

It is important to remember that the PLC itself is not always the source of the issue. In industrial environments, field devices, sensors, wiring, actuators, and communication equipment are often more exposed to environmental conditions and can fail more frequently than the PLC CPU itself.

Network Issues

PLCs and the devices connected in networks can fail over time, either due to faults, misconfiguration, changes in the network, or failed components.

Often in PLC configurations inside panels, components can fail due to static discharges or electromagnetic interference. You’d need to slowly identify which router, PLC, switch, computer, or cabling is affecting the network.

It can often be traced back to devices not picking up any data, not being able to make any API requests, losing communication with HMIs or remote I/O devices, or being unable to access the network altogether.

Repeated communication dropouts, intermittent Ethernet connectivity, or devices randomly disconnecting from the network can also indicate degrading communication hardware or damaged Ethernet cabling.

In some situations, outputs may remain active when they should not be, or equipment may fail to respond even though sensors appear to be operating correctly. This can indicate communication faults, failed I/O modules, or logic-related issues.

Need assistance troubleshooting Ethernet communication on PLC systems? Check out our troubleshooting Ethernet on PLCs guide.

The post Signs of a Failing PLC appeared first on Control Hub.

Some applications require a PLC to communicate with different modules or devices via Ethernet.
This makes it easier to transfer data or send commands to different machines/devices.

Due to a lack of maintenance or incorrect configuration, Ethernet connections can fail. You’d need to troubleshoot at the correct source to figure out how to resolve the specific issue. Always identify what the issue is before attempting to solve it; you can’t solve a problem you haven’t defined.

Process of Elimination

The best course of action is to systematically check where the issue is:

1. Check Ethernet Interface: Check the physical lights on the Ethernet interface. If no lights appear, the interface could be faulty.
2. Check Ethernet Cable: Take a known working device and see if the cable works in another device.
3. Check PLC Communication: Check if the PLC can communicate with another device, and attempt to ping the device.

Check Ethernet Interface

Ethernet interfaces have built-in LEDs to indicate link status and network activity. If no lights appear on the physical interface, you could potentially have a network issue stemming from broken Ethernet cabling, powered-down devices, broken Ethernet interfaces, or in some cases, incorrect network configuration.

Look for physical damage on the board. Is there any burnt residue near or on the port? If not, move on; it could mean other factors.

If physical damage is present, you can either replace the communication module or attempt a repair by physically desoldering and resoldering a replacement Ethernet port to the PCB. In the case of a PLC Ethernet interface, it is possible to repair, but no guarantees can be made that it will work due to manufacturer-specific hardware and firmware implementations on the PLC. You will be repairing at your own risk.

After replacing or fixing the Ethernet interface on either the I/O or the PLC, or both, reconnect the system and see if the system is operational again.

Check Ethernet Cable

Ethernet cables can break over time due to excessive bending of the cabling, mishandling of equipment, or potential machine breakdowns.

Replace with appropriately rated Ethernet cabling if the cabling has been damaged. Reconnect the cabling to the relevant interfaces and see if communication is restored. If not, you could have a misconfiguration issue.

Check PLC Communication

For the PLC and the I/O device to be able to communicate over Ethernet, a physical connection through an Ethernet cable has to be made. Both of these devices then get assigned an IP address.

Both devices have to have an IP address on the same network to communicate with each other. On already commissioned PLC installations, there should be an IP address for the PLC near the installation inside a cabinet. You can connect a laptop and simply attempt to ping that IP address. If that does come through, then you know the cabling and the PLC’s IP configuration are correct. If not, the PLC could be incorrectly set up.

This goes for the I/O device too; attempt to ping the I/O device with a laptop Ethernet connection. If a ping does come through, communication is established. If not, the I/O device could be misconfigured.

Also verify that subnet masks are configured correctly and that no duplicate IP addresses exist on the network.

Finally, connect both the PLC and the I/O device and see if communication is restored. If communication is restored, the issue has likely been resolved. Otherwise, IP configuration could still be a problem. Go over both IP configurations and try again.

Summary

Essentially, check the Ethernet cable, check if the PLC can communicate with another device, and check the physical interfaces on both the PLC and I/O. You should be able to go from there and replace the cabling or interface if you know how to solder.

If any of the mentioned equipment, Ethernet cabling, and interfaces still have a warranty, it is advisable to use them. Do not attempt to repair equipment under warranty, as you have a chance to void the warranty.

The post Troubleshooting Ethernet on PLCs appeared first on Control Hub.

SAN 10142-1 Specification

Overview

According to the ECA, the South African National Standards (SANS 10142-1) were officially written and set as the standard for premises electrical installations in 2001. The specification has undergone multiple iterations and has now set forth multiple rules, regulations, and guidelines for low-voltage installation.

Regarding acquiring the full specification, the SANS 10142-1 can be purchased on the official ECA website. Please find it here. If you’d like to get an overview of the specification, please read up on the history of the specification.

Low Voltage Installations

In accordance with SANS 10142-1, every residential and industrial low voltage electrical installation in South Africa is required to have a main switch disconnector on each distribution board, providing an immediately accessible means to disconnect the entire installation in an emergency, for maintenance, or in the event of a fault — as mandated under the Occupational Health and Safety Act.

The important of the SAN 10142-1 Specification

According to the SANS 10142-1 specification, residential and industrial electrical installations must have a distribution board (your DB) that provides an easily accessible means of disconnecting the main power supply to the house, industrial area, or specific niche installation, such as solar systems, in the event of an emergency.

This allows you, electricians, and any accredited electrical installer to easily disconnect power to troubleshoot faults without having to disconnect multiple sources of power.

Without this single source of truth, isolating faults and potential power hazards would be prevalent, increasing the resolution time and risk to anyone working on the installation.

Main Switch Circuit Breaker

Photo by proudlyswazi on Unsplash

In the case of your home (residential), this main switch disconnector is the main switch circuit breaker.

That signature trip that you hear when loadshedding is over, or when you’ve got both the kettle and tumble dryer pulling a electrical load, is when the circuit breaker protects your electrical systems.

The main switch circuit breaker, based on the type of circuit breaker, will physically disconnect the contacts and sever the electrical connection to your home’s electrical circuit, protecting the entire home’s electrical systems from overcurrent, undervoltage, shock current, and even electrical arcs.

Where is the circuit breaker located?

As per the SANS 10142-1 specification, the main switch circuit breaker must be mounted:

• Main or First Distribution board (db): In the distribution board or adjacent to the distribution board in the same room as the distribution board itself. The circuit breaker itself must be labeled as “Main Switch”.
• Sub-distribution board: Same specification as a main distribution board although the circuit breaker must be labelled as “sub-main switch” or “main switch” if the board is labelled “sub-board”.
• Alternative Supply: Same specification as main distribution board although the circuit breaker must be labelled as “main switch” and must have a notice displayed at it stating that an alternative supply is connected to the installation. Where the alternative supply only feeds certain circuits, a power-on indicator (visible or audible) must also be provided on the distribution board, along with a notice stating that the standby power main switch must also be switched off in an emergency.
• Danger Notice: A danger notice must be provided near or on the circuit breaker that provides instructions that the breaker be switched off in the “event of inadvent contact or leakage”.

Most likely, you’ll find your main switch circuit breaker near or in the distribution board, with a danger notice and labelled as “main switch” for your home (residentual).

Regarding non-residentual installations or other international electrical installations, typical locations would be in the distribution board, near distribution boards, electrical panels, or near electrical meters.

Summary

Main Switch circuit breakers are required as per the SANS 10142-1 specification in low-voltage installations to provide an easy means of powering off the entire installation, making it easier to troubleshoot faults and safer by allowing a single point of power shutoff in emergency cases.

As a homeowner or installer, you can find the main switch circuit breaker near or in a distribution board in residential low-voltage installations.

The  main switch circuit breaker’s  purpose is to disconnect power to the entire electrical installation in cases of electrical surges, overcurrent, or electrical arcs. Protecting the underlying electrical system

Need a circuit breaker for your next project? Browse our full range and find the right fit.

The post The Main Switch Circuit Breaker: Your Home’s Electrical Lifeline appeared first on Control Hub.

Whether you’re adding a conduit entry, fitting a cable gland, or mounting an industrial socket, cutting a clean hole in a distribution board is one of those tasks that looks simple but can go wrong fast. A ragged edge, a cracked enclosure, or a misaligned hole can compromise the board’s IP rating, create safety hazards, and give the impression of unprofessionalism.

What’s an IP rating?

As defined by the IEC, an ingress protection (IP) rating grades the degree to which an enclosure resists the intrusion of dust or liquids, indicating how well an enclosure will resist access to foreign particles in various environments.

The IEC defines two numerals in the IP (IPxy) rating to provide a quick overview:

• Solid particle protection (first numeral): A rating from 0 (no protection) to 6 (full dust-tight) indicating whether the enclosure resists solid particle ingress. It essentially checks whether any dust or dirt can enter the container over time.
• Liquid ingress protection (second numeral): A rating from 0 (no protection) to 9 (high-pressure hot water at different angles) indicating whether the enclosure resists liquid ingress. It essentially checks whether  any high-pressure jetted warm liquids enter the internals of the container.

IP rating example

Commonly, IP ratings are found on manufactured phone specifications to grade how well the case would resist water or dust entering the mobile device. A good example would be the latest iPhone 17 Pro. The phone has an IP rating of IP68.

The IP rating of IP68, according to the IEC’s definition of ingress protection (IP), classifies the iPhone 17’s container as stopping any solid particles  and being able to be submerged for an extended period of time.

Similarly, when cutting through your enclosures, you’d want to keep the enclosure’s IP rating intact. This ensures minimal ingress of dust or liquids that could damage electronics and cause electrical shorts.

Risks from Poor Cuts

A distribution board is designed and manufactured to protect electrical components from dust, moisture, and general impact. Incorrectly cutting into the distribution board could risk:

• Cracking plastic enclosures: This makes the enclosure structurally weaker and more resistant to impacts.
• Deforming metal panels: This makes it difficult to evenly fit fittings and other glands.
• Compromising the IP rating: An oversized or rough hole allows moisture and dust into the panel, increasing the risks of fires.
• Cutting cables: Roughly cut holes leave behind sharp burrs; friction over time could cause the cables to snag and damage them.
• Voiding Certification: Distribution boards have to be inspected by relevant construction and electrical laws; the modified enclosure may not pass inspection.

Avoiding these risks is paramount for safe, certified installations. Reducing the overall time and money spent on re-evaluating the installation, cut once, and move on.

Step 1: Identify the Board Material

Distribution Boards can be manufactured to have different materials, ranging from steel to plastic. Different tools are needed for cutting into these materials.

Plastic: Step Drill Bit

Plastic distribution boards are common in residential and light commercial installations. Plastic, generally, is far easier to work with, although it is prone to cracking under too much force or drilling/cutting with the wrong bits.

Step drills remain the best option for cutting through these plastic enclosures, self-starting without a pilot hole and gradually applying cutting pressure. This leads to a clean round hole with minimal cracking or plastic distortion.

It’s advisable to start off slow and allow the bit to do its work; applying too much pressure typically results in greater heat, which melts and distorts the plastic.

Steel and Metal: Knockout Punch

For steel panels and metal distribution boards, a knockout punch is the professional’s choice. It shears cleanly through the metal in a single controlled action, leaving a smooth burr-free edge that seats fittings perfectly. Unlike drilling, it produces no sparks, no heat distortion, and no rough edges that could damage cables.

For smaller holes in thinner steel, a step drill bit or hole saw can also work well, but for anything above 20mm in a steel enclosure, a knockout punch will give you a far cleaner result.

When to Use a Hole Saw

Hole saws are useful when you need larger diameter holes. For example, fitting a large cable gland or a CEE industrial socket. They work on both plastic and metal, but require more care to keep the cut straight and clean. Always use the correct blade type for your material: bi-metal for steel, carbon, or HSS for plastic.

Step 2: Mark and Measure Carefully

Measure twice, cut once. Measuring and carefully cutting avoids expensive mistakes and allows you to plan how to effectively cut in limited, cramped spaces.

1. Use a center punch to mark your drill point, reducing the chances of wandering from your target.
2. For plastic enclosures, simply use a pencil or marker. Using a center punch on plastic can crack the surface; avoid it.
3. Use a hole template or fitting to trace the exact diameter needed.
4. Double check, make sure your hole won’t interfere with internal bushbars, terminals, or DIN rails.

Step 3: Secure the Enclosure

Never try to cut holes into distribution boards that can be moved with live components inside.

Always:

1. Work on uninstalled enclosures.
2. Secure it to a workbench so it doesn’t move during the cutting process.
3. Remove all the internal components that could potentially be damaged by swarf or plastic debris.
4. If cutting into a fixed or installed board, switch off and isolate the supply first.

Step 4: Cut the Hole

For Plastic with a Step Drill Bit:

1. Start at low speed and let the tip find its position.
2. Increase speed gradually once cutting has started.
3. Stop at the correct step diameter.
4. Clear debris regularly to prevent heat buildup.

For Metal with a Knockout Punch:

1. Drill a small pilot hole at your marked centre point.
2. Insert the draw stud through the pilot hole.
3. Thread the punch on one side and the die on the other.
4. Tighten the draw stud with a wrench until the punch shears cleanly through the metal.
5. Remove the slug

For Larger Holes with a Hole Saw:

1. Use a centre punch on metal to start the pilot drill.
2. Run at moderate speed with steady, even pressure.
3. Use cutting lubricant on metal to reduce heat and extend blade life.
4. Back out regularly to clear swarf and cool the blade.

Step 5: Clean Up the Edge

Even the cleanest cut benefits from a quick finish:

• Deburr metal edges with a deburring tool or fine file. Sharp edges will cut through cable insulation over time, deburr them.
• Smooth plastic edges lightly with fine sandpaper if needed.
• Check the fit of your fitting, gland, or socket before final installation. The fitting should seat flush with no rocking.

Step 6: Maintain the IP Rating

This is where many installers fall short. Cutting the hole is only half the job — sealing it correctly is what maintains the enclosure’s protection rating.

• Always use a cable gland rated to the same or higher IP level as the enclosure.
• Ensure glands are tightened correctly.
• For unused holes, fit blanking plugs. An open hole immediately drops your IP rating to zero.
• Check the gland manufacturer’s recommended hole size.

Summary

Cutting a clean hole in a distribution board comes down to three things:

1. The right tool for the material
2. Careful marking
3. A proper finish

Rushing any of these steps risks damaging an expensive enclosure or creating a safety issue down the line.

Whether you’re reaching for a step drill, a knockout punch, or a hole saw, the goal is always the same: a clean, correctly sized hole that seats your fitting perfectly and keeps your IP rating intact.

Looking for the right tools for your next panel installation?

Browse our range of step drill bits, knockout punches, hole saws, cable glands, and blanking plugs.

The post How to Cut Clean Holes in a Distribution Board Without Damaging It appeared first on Control Hub.

Ever had a circuit breaker in your hand, flicking the switch for the satisfying click, and then stopped to wonder – why?

Why does the breaker toggle have a colour? Red, black, blue, what does it mean?

Circuit Breakers

Circuit breakers are electrical safety devices designed to protect circuits from excessive current, known as overcurrent.

They automatically interrupt the flow of electricity when a fault occurs, helping prevent damage to equipment and wiring, and reducing the risk of fire.

When a fault occurs, the breaker will “trip”, moving the toggle from the ON position to the OFF position, disconnecting the electrical circuit.

Toggle Colour

All circuit breakers have a maximum fault current that they can safely interrupt without failure, known as the breaking capacity.

Some manufacturers may use different toggle colours to distinguish between product ranges, which can include breakers with different breaking capacities (typically expressed in kA).

However, this is not standardized across the industry. Colour should not be relied upon as a definitive indicator of a breaker’s rating.

All circuit breakers clearly display their breaking capacity on the device itself. When in doubt, always refer to the markings on the breaker or the manufacturer’s technical documentation for guidance.

Summary

Circuit breakers provide a simple yet effective way of protecting electrical circuits, primarily governed by their rated current and breaking capacity.

While some manufacturers may use colour coding as a visual aid, it should only be used for quick identification—not as a substitute for technical specifications.

Before installation or system design, always verify the breaker’s ratings using the printed information or official product documentation.

When selecting a circuit breaker, it’s important to choose the correct rated current and breaking capacity. You can browse suitable options in our circuit breaker range.

The post Why Circuit Breaker Toggles Have Different Colours (And What They Mean) appeared first on Control Hub.

When an electrical system fails, the instinct is to look at components, the drive, the relay, the sensor. Components are tangible, testable, replaceable. But the data tells a different story. In the majority of electrical failures, the component itself is intact. What failed was the connection between components. The point where two things meet turned out to be the weakest point in the system.

The Connection Is the System

Every circuit is only as reliable as its least reliable junction. A cable rated for 600V and 30 years of service delivers exactly that, right up to the terminal block where it was under-torqued during installation. A sensor rated to IP67 fails because the connector it plugs into was never rated for the environment it operates in.

Connections are, by nature, transition points. They’re where different materials meet, where mechanical forces concentrate, where environmental exposure is highest, and where installation quality has the most direct impact on long-term performance. This is why connection failures account for a disproportionate share of electrical faults, not because they’re poorly designed, but because they’re uniquely vulnerable to everything that happens after design.

A system is only as strong as its weakest point, and that point is almost always where two things meet.

Four Causes That Appear in Almost Every Failure Analysis

1. Loose Terminations

Vibration is the silent untightener. A correctly torqued terminal that starts at specification can work loose over months of mechanical vibration from adjacent machinery, thermal cycling, or cable movement. As the clamping force reduces, contact resistance increases, and with it, heat. Heat accelerates oxidation of contact surfaces, which increases resistance further. This self-reinforcing cycle is why loose connections rarely stay at “minor issue”, they progress.

2. Incorrect Crimping

A crimp is a cold weld between conductor and terminal. Done correctly with the right tool and die, it creates a gas-tight, mechanically sound joint that will outlast the cable. Done incorrectly, wrong tool, wrong die, misaligned conductor, under or over-crimped , and the joint has voids that trap moisture, microscopic gaps that oxidise, and reduced mechanical strength that fails under load or vibration. The external appearance of a bad crimp is often indistinguishable from a good one.

3. Poor-Quality Connectors

Not all connectors are equal, and the difference is rarely visible at purchase. Low-quality connectors use thinner plating that wears through faster, base materials that corrode more readily, and contact geometries that deliver lower normal force, meaning less reliable electrical contact under load. Under the same operating conditions, a budget connector can fail in months where a properly specified industrial connector would have run for years.

4. Environmental Exposure

Moisture, dust, vibration, and chemical exposure all attack connections from the outside. Moisture bridges contacts and accelerates galvanic corrosion, particularly at dissimilar metal junctions. Conductive dust builds resistive films across open contacts. Chemical exposure, oils, cleaning agents, process gases, degrades both the contact surfaces and the polymer housings that hold them in alignment. An unprotected connector in a washdown or chemical-adjacent environment is not a long-term solution, regardless of initial quality.

The Failure Progression

How a Small Issue Becomes a Shutdown

Connection failures rarely announce themselves. They develop gradually through a predictable chain, one that’s entirely preventable if caught early, and increasingly expensive the further along the chain it runs.

Failure Progression Chain

• 1. Poor contact: Loose terminal, bad crimp, or oxidised surface creates a resistive junction
• 2. Heat Builds: Resistance generates localised heat, accelerating oxidation and material degradation.
• 3. Failure: Open circuit, arc fault, or downstream component damage, often with no warnin

The insidious part of this progression is its invisibility. Increased resistance at a terminal doesn’t trigger an alarm. The heat it generates may not be enough to trip a thermal sensor. The system continues operating, degraded, but apparently functional, until the failure threshold is crossed. At that point the fault presents as a sudden, unexplained failure rather than the gradual deterioration it actually was.

What Good Connection Practice Actually Looks Like

The fundamentals are well established. The gap between knowing them and consistently applying them across an entire installation is where failures are born.

Good Connection Practices:

• Specify connectors for the environment: IP rating, temperature range, chemical compatibility, and vibration resistance should all be matched to actual operating conditions, not selected from the lowest-cost catalogue option that meets the nominal voltage and current spec.
• Use calibrated crimp tooling: The correct die for the terminal and conductor cross-section is non-negotiable. Ratchet-style crimp tools that cannot be released before the cycle completes are the minimum standard for production environments.
• Apply and verify torque values: Terminal manufacturer torque specifications exist for a reason. Torque-controlled drivers and documented torque checks at commissioning are the only reliable way to know terminals are correctly clamped.
• Include connections in your inspection regime: Thermal imaging of electrical panels during operation is one of the most cost-effective predictive maintenance tools available. Hotspots at terminals and connectors are detectable well before failure , often months in advance.
• Retorque after the first thermal cycle: Many terminal manufacturers recommend a re-torque check after initial load cycles. Thermal expansion and settling can reduce clamp force in the first weeks of operation, catching this early prevents the progressive loosening cycle entirely.

Good Connections Are Not
Just About Installation.

They’re about every decision made before, during, and after, the specification, the tooling, the torque, and the inspection that catches the problem before it becomes a failure.

The post The Real Reason Electrical Connections Fail appeared first on Control Hub.

The assumption is almost universal in industry: PLCs are rugged hardware. They’re built to run in harsh plants, tolerate electrical noise, and survive decades in panel boards. That reputation for toughness, however, refers to PLCs in operation, correctly installed, properly ventilated, and within spec. A PLC sitting in a warehouse is a different story entirely.

The Damage Nobody Sees Coming

Every year, industrial facilities commission new equipment, pull PLCs from storage, and encounter the same bewildering problem: a unit that tested fine at the supplier fails on first startup. Or worse, it starts up, runs for a short period under load, and then fails unpredictably in the weeks that follow.

The root cause, in a significant number of these cases, is not a manufacturing defect. It’s what happened in the warehouse. Improper storage degrades precision electronics silently and progressively, leaving no visible evidence and no obvious fault code, just a component that’s already past its prime before it ever enters service.

A PLC doesn’t need to be running to be damaged. The warehouse environment can begin degrading sensitive electronics long before the unit is ever switched on.

The Four Silent Threats in Storage

1. Humidity & Condensation

Moisture infiltrates circuit boards and corrodes copper traces, component leads, and connector pins, damage that may not manifest until the board heats up under load. A single condensation event can bridge conductors or initiate corrosion that progresses invisibly for months.

2. Electrostatic Discharge

The human body can carry thousands of volts of static charge. A single unprotected handling event can punch through gate oxides in CMOS components, causing immediate failure or, more dangerously, latent damage that weakens the device without killing it outright.

3. Temperature Extremes

Thermal cycling, repeated heating and cooling across a wide range, stresses solder joints, expands and contracts component housings, and can crack PCB substrates. A PLC stored in an uncontrolled outdoor container or near a roof in summer is accumulating stress with every day that passes.

4. Dust & Contamination

Conductive dust particles settling on open boards or inside unsealed enclosures create resistive or capacitive paths between conductors. Fine metallic dust, common in fabrication environments, is particularly destructive, creating short-circuit paths that are invisible to the naked eye.

Latent damage is the most dangerous kind

 A PLC with ESD damage or corrosion-weakened solder joints may start up and pass initial testing, only to fail weeks later under thermal load or vibration. By that point, the storage origin of the failure is rarely suspected, and the unit is often replaced rather than root caused.

How to Store PLCs Correctly

None of the requirements for proper PLC storage are exotic or expensive. They’re basic environmental disciplines that protect a significant capital investment. The problem isn’t a lack of available solutions, it’s that the risk is invisible until it isn’t.

Essential Storage Factors:

• Controlled Temperature: Store between 0°C and 40°C, away from heat sources, roof exposure, and direct sunlight. Avoid spaces with large daily temperature swings.
• Dry Conditions: Maintain relative humidity below 60%. Use desiccant packs inside packaging for long-term storage. Never store on concrete floors where moisture can wick upward.
• Anti-Static Protection: Keep units in original anti-static bags or ESD-rated packaging. Handle with grounded wrist straps. Never place on or near synthetic surfaces or foam that hasn’t been ESD-rated.
• Sealed Packaging: Original manufacturer packaging is designed to protect against all of the above threats. Once opened, reseal in clean polyethylene bags with desiccant before returning to storage.

For high-value or long-term storage, spares held for critical systems, consider a dedicated electronics storage cabinet with humidity control. The cost of a storage cabinet is trivial compared to the cost of a failed PLC on a production-critical line.

The Broader Principle: Failure Doesn’t Wait for Commissioning

The conventional model of industrial reliability focuses on operating conditions, temperature in service, vibration loads, duty cycles. These matter enormously. But the clock starts running the moment equipment leaves the manufacturer, and every phase of its journey before commissioning is an opportunity for degradation.

Transport shocks, improper stacking, uncontrolled storage environments, unprotected handling, each one places stress on precision electronics that were designed to operate within specific bounds. When those bounds are violated in the warehouse, the consequences show up on the production floor.

Treating PLCs and other sensitive control hardware with the same rigour in storage as in service isn’t overcautious. It’s the minimum standard for protecting capital equipment and ensuring that what gets commissioned is what was purchased: a fully capable, uncompromised unit.

Industrial Equipment Can Fail
Before It’s Ever Switched On.

The warehouse is not a neutral environment. Treat your control hardware accordingly and protect your commissioning day from the damage that started months before it.

The post What Happens When PLCs Are Stored Incorrectly appeared first on Control Hub.

In most industrial plants, cabling is treated as a commodity, a background decision, something you “just need to connect things.” The problem with that mindset? It holds until 3am on a Tuesday, when a failed cable shuts down an entire production line and that “saved” R200 becomes a R200,000 downtime event.

The Invisible Backbone of Every Plant

Walk through any manufacturing facility and you’ll find them everywhere, bundled, routed, clipped, and largely ignored. Cables. Miles of them. They carry signals, power, and data between every sensor, drive, motor, and controller in the building. And yet, they are almost universally treated as an afterthought.

The engineering hours go into specifying the right PLC, the right VFD, the right motor. The cable connecting them? “We’ll figure that out during procurement.” It’s a decision made on price alone, with no reference to the actual operating environment the cable will live in.

This is one of the most common, and most costly, silent mistakes in industrial maintenance.

Cable selection is not about getting power from point A to point B. It’s about ensuring reliability under the real conditions your plant actually runs in.

Real Conditions Are Brutal

The test lab doesn’t care about your installation. Your plant does. Consider what a cable experiences in a real industrial environment:

• Sustained heat: Cables near motors, furnaces, or in poorly ventilated conduits can see temperatures that degrade standard PVC insulation over months, not years.
• Constant vibration: Machinery transmits vibration through frames, panels, and cable trays. Over time, this fatigues conductors at termination points.
• Chemical and oil exposure: Coolants, hydraulic fluid, cutting oil, and cleaning agents attack non-rated cable jackets, causing swelling, cracking, and insulation breakdown.
• UV and outdoor exposure: standard cables used in outdoor runs degrade rapidly under UV, with jackets becoming brittle and cracking within 12-18 months.
• Repeated flexing and movement: Drag chains, robotic arms, and moving carriages bend cables thousands of times daily. Standard cables were never built for this.

Three Mistakes That Cost Plants Every Year

1: General-Purpose Cable in Harsh Environments

This is the most prevalent error. A general-purpose cable is designed for mild, static, indoor environments. Put it near a hydraulic press, a coolant nozzle, or a heat-generating drive cabinet, and the clock starts ticking immediately.

Oil-resistant cables, UV-stabilised outer jackets, and high-temperature-rated insulation exist precisely because standard cable fails in these conditions. These are not premium upsells, they are the right tool for the job.

2: Ignoring Movement and Bending Radius

In any application involving a drag chain, a sliding gantry, a robot arm, or any moving axis, cable selection becomes critical engineering. Every bend cycle stresses the conductor and the insulation. Standard fixed-installation cables fail prematurely, often within weeks, in high-cycle applications. Flex-rated cables are constructed with finely stranded conductors, specially formulated jackets, and controlled pitch lay specifically to survive millions of bend cycles. Using the wrong cable here isn’t a cost saving, it’s a guaranteed maintenance problem.

3: Underspecifying to Save on Upfront Cost

The economics feel compelling in the moment: the specified cable costs R180 per metre, the alternative is R60 per metre, and there are 200 metres to run. You save R24,000. What this calculation never includes is the labour cost of replacement, the production losses during downtime, the emergency procurement premium when you need cable urgently, and the cascading damage when a cable fault takes out a connected drive or sensor.

The true cost of a failed cable is rarely just the cable itself:

• High Voltage Management reported that 42% of unplanned downtime costs are equipment-origin. Implementing a rigorous cable management strategy ensures your infrastructure isn’t part of that statistic.
• Heavy Vehicle Inspection & Maintenace reported that reactive maintenance can costs 3–9 times more than planned maintenance. Proactive cabling oversight is the simplest way to avoid these massive emergency premiums.
• ABB’s survey revealed that on average, it costs $125K per hour of unplanned outage. High-quality cabling standards are a low-cost insurance policy against these high-stakes outages.

How to Think About Cable Selection Correctly

The right framework is not “what’s the cheapest cable that meets the nominal spec?” It’s: “What environment will this cable actually operate in, and what does that demand from it?”

This means thinking through temperature rating, chemical exposure, mechanical stress, movement cycles, UV exposure, and installation method before specifying. It means reading the application, not just the datasheet line for conductor size and voltage rating.

For critical applications, servo drives, drag chains, outdoor runs, chemical-adjacent installations, specify cables that are tested and rated for exactly those conditions. The certification markings on industrial cable (oil-resistance, flex-cycle ratings, UV stability, temperature range) aren’t marketing language. They represent real test data that tells you whether the cable will survive your environment.

For standard panel wiring and fixed runs in benign environments, general-purpose cable is entirely appropriate. The discipline is in accurately reading the environment and matching the spec to reality.

The Reliability Argument

Every component in your system has a role in the overall reliability number. Engineers obsess over drive MTBF, sensor ratings, and bearing life, but rarely apply the same rigour to cable selection. Yet a cable is the connective tissue of your system. When it fails, everything it connects fails with it.

A correctly specified cable for its environment will outlast the equipment it serves. An incorrectly specified one will be replaced repeatedly, and each replacement carries the full cost of labour, downtime, and opportunistic damage. The cable is not a cost to be minimised. It is a reliability investment to be specified correctly.

A Cable Is Not Just a Cost

It’s a structural part of your system reliability. Specify it like one, and your plant will thank you in uptime, not in emergency callouts.

The post Why Your Cable Choice Matters Far More Than You Think appeared first on Control Hub.