We’ve reviewed projects that had everything going for them good equipment, capable contractors, realistic schedules and still ran into serious problems during construction. In most of those cases, the cabling was the culprit. Trays that were sized without looking at what would actually run through them. Routes that crossed every major pipe rack in the plant. Instrumentation cables bundled with power cables because nobody had drawn a segregation boundary. None of it was negligent. It was just not planned carefully enough, early enough.
That’s the work iFluids Engineering does. We plan cable routing properly, at the right stage, and produce the drawings and schedules that a contractor can actually build from. Not concept sketches that someone interprets on site. Not cable lists with no route references. Proper, coordinated, standards-compliant cable routing design from the first tray layout to the as-built record.
If you’ve landed on this page because something has gone sideways on an existing project, we can help with that too. But the bigger opportunity is always upstream.
What exactly is a conceptual cable routing layout?
It’s the document that answers, at a high level, where all the cables go. Not every cable, not at this stage. The highways. The main tray routes carrying HV and LV power across the facility. The separate routes for instrumentation and control cables. Where those routes intersect with structural steel, pipe racks, buildings, and roads, and how they get past them. Where the junction boxes and marshalling panels will sit to break long runs into manageable sections.
A conceptual cable routing layout is the routing philosophy made visible. It is the document you use to get agreement before you commit to detail.
It deliberately does not go into the detail of individual cables. That comes later, in the wire routing diagram and cable schedule. The conceptual layout is for establishing routes that work routes that are physically possible, segregated correctly, sized for what will run through them, and agreed with the client before the detailed design machine starts moving.
Projects that skip this stage and go straight to detailed design almost always end up revisiting the same decisions halfway through once the piping model has matured, once the structural design is fixed, once procurement has already started. At that point, rerouting a main cable tray run is not a drawing change. It is a project event. The conceptual cable routing layout exists to prevent that.
Why cable routing layout matters and where it goes wrong
Cable routing is one of those disciplines where the consequences of getting it wrong are largely invisible until they are not. The project looks fine. Cables are being pulled. Trays are going up. And then commissioning starts and half the instrumentation readings are unreliable because instrumentation cables were run in the same tray as variable speed drives. Or maintenance finds that tracing a single fault means disturbing six other cables because nothing was routed with access in mind. Or the client wants to add a new pump and discovers there is no spare capacity in any of the trays serving that area.
None of those are dramatic failures. They are the slow, expensive kind — the ones that accumulate over the life of the facility.
Recognized for excellence.
PROJECTS DELIVERED ACROSS THE GLOBE
Signal interference
Power cables generate electromagnetic interference. Instrumentation cables carrying low-level signals, thermocouple signals, 4–20mA loops, pulse outputs from flow meters are sensitive to it. Run them together without separation and the signals degrade. Sometimes subtly, sometimes enough to render a measurement useless. A proper cable management layout defines the separation required between cable classes and specifies what happens at crossings, which are unavoidable on any real project.
Compliance isn’t optional
IEC 60364, BS 7671, NEC, NFPA 70, IEC 60092 for marine work every project has a governing standard, and it has specific requirements that the cable routing design has to meet. Bend radius limits, fill ratios, earthing requirements, fire barrier penetration details, cable support spacing. These are not suggestions. A routing design that ignores them generates non-conformances during construction inspection and creates liability exposure for the plant operator.
Maintenance time is a real cost
A plant where cables are routed logically, labelled consistently, and installed to match the wire routing diagram is a plant where fault finding takes minutes. A plant where the installed cabling has drifted from any drawing that exists where cables were rerouted on site without documentation, where labels have faded or were never applied is a plant where maintenance teams spend hours on problems that should take twenty minutes. Over ten years of operation, that difference is significant.
Cable isn’t cheap
Nor is tray, nor are the men installing it. A cable routing design that finds the shortest defensible route for each cable, shares tray runs where segregation rules allow, and positions intermediate boxes intelligently can reduce total cable quantities by 10 to 20 percent on a mid-size project. On a large petrochemical plant, that is hundreds of thousands of pounds worth of material and labour. It is not over-engineering. It is doing the job properly.
Future changes happen
Every facility gets modified. New equipment gets added, process changes need additional instrumentation, communication infrastructure gets upgraded. If the tray routes are already running at or near capacity, if the routing is too tangled to add a cable without disturbing a dozen others, those modifications become expensive and disruptive. Planning in spare capacity from the outset is cheap. Retrofitting it is not.
How we approach cable routing layout design
We don’t have a proprietary framework with a name. We have a process that works, refined across a lot of projects in a lot of sectors.
We understand the project before we draw anything
Load lists, P&IDs, equipment arrangement drawings, hazardous area drawings, applicable codes and standards, client engineering preferences. We gather this before the first tray route gets sketched. The number of routing problems that trace back to assumptions made because someone didn’t read the hazardous area drawing is higher than it should be.
We develop the conceptual layout and get it agreed
With the project information in hand, we produce the conceptual cable routing layout, the primary tray routes, conduit highways, segregation zones, major junction box positions. We present it to the client for review and agreement. Once the routing philosophy is locked, the detailed work proceeds without constant direction changes. This step is worth its cost many times over on any project of real complexity.
We produce the detailed wire routing diagrams and cable schedule
The detailed wire routing diagram shows exactly where each cable runs: which tray or conduit, which route, which junction boxes it passes through, where it terminates at both ends. Alongside it, the cable schedule lists every cable on the project tag, type, voltage rating, conductor size, route reference, length, drum number. The contractor works from both documents. One without the other is not enough.
We check for clashes and fix the numbers
On 3D-modelled projects, we route through the model and run clash detection. We also check tray fill ratios power cable trays to 40%, instrumentation and control trays to around 50%. Leaving headroom costs almost nothing at design stage and avoids a great deal of pain when the first modification project comes along.
We issue for construction, and we document what was actually built
The IFC package has the routing drawings, cable schedule, installation notes, and any hold points the contractor needs to observe. After construction, we produce the as-built cable management layout, the record of what was actually installed. That document is what the next engineer who works on this facility will rely on. It deserves to be accurate.
What we deliver
Our cable routing work covers the full project lifecycle. Here is what that looks like in practice.
Conceptual cable routing layout
The high-level routing schematic: primary tray routes, conduit highways, segregation zones, major junction box positions. Used for client sign-off, cost estimation, and multi-discipline coordination before detailed design begins. This is the document that prevents the expensive rework.
Detailed wire routing diagram
Construction ready routing drawings showing every cable’s route through the facility tray and conduit references, junction box positions, penetration details, termination points. Built to the applicable standard and reviewed before issue.
Cable management layout and tray design
Tray sizing, ladder rack selection, fill calculations, support spacing, cable cleat requirements, fire stop details at penetrations. The mechanical side of the cable routing design. It is also the side most commonly underspecified on projects that run into installation problems.
Cable schedule and drum schedule
A complete cable register every cable, every detail, procurement ready. The drum schedule tells the contractor how to order cable so that joints are minimized and lengths aren’t wasted. It is one of the most useful documents on a construction site, and one of the most frequently missing on projects that didn’t plan properly.
3D cable routing
For projects using AVEVA E3D, Bentley OpenPlant, or AutoCAD Plant 3D, we route cables in the model and run automated clash detection. Material take-offs come directly from the model. On large or complex projects with dense multi-discipline interfaces, the 3D approach earns its cost quickly.
Cable routing for machinery and skid packages
Wire harness layouts inside control panels, drag chain routes for moving machine axes, conduit arrangements within enclosures, connector placement. Designed with the Machinery Directive and EMC requirements in mind, and documented with wire routing diagrams the installation team can actually follow.
Structured cabling for offices and commercial buildings
TIA-568 and ISO 11801 compliant structured cabling design: telecommunications room layouts, fibre backbone routes, horizontal cable distribution, patch panel schedules. Not a side service, we have designed structured cabling for large commercial fit-outs and we know the difference between a cabling layout that works on day one and one that works for the ten years after that too.
Offshore and subsea cable routing
Hazardous area cable routing on FPSOs and offshore platforms is a different discipline in important respects. We work to NORSOK, API, and IEC 60092. Ex-rated cable selection, firewall penetration details, ATEX zone segregation, and the structural constraints of a floating installation. We also know how much more expensive it is to fix routing mistakes offshore than onshore.
Where do cables go inside machinery?
It depends on what the machine does and whether anything moves.
For static machinery Pumps, compressors, heat exchangers, the principles are straightforward. Route along the structural frame where possible. Use conduit or armoured cable wherever there is any risk of physical contact or mechanical damage. Keep power cables away from signal cables, ideally on opposite sides of the frame. Clamp at regular intervals and eliminate free-hanging spans, vibration finds them eventually.
For machines with moving axes, robotic arms, CNC machines, indexing tables the routing problem is fundamentally different. The cables have to move repeatedly, for years, without fatiguing. This is what drag chains and cable carriers are for. The cable runs through a chain that flexes as the axis moves, maintaining a defined bend radius throughout its travel. Selecting the wrong cable type here one not rated for continuous flexing is a reliable way to get intermittent faults that are hard to diagnose and expensive to fix.
Cables inside machinery need a defined home — a path, a clamp point, a length. Anything left loose will eventually fatigue, chafe, or get caught in something
Our wire routing diagrams for machinery show connector positions, cable entry points, clamp locations, minimum bend radii, drag chain specifications, and the intended path through the machine. The installer should not be making routing decisions on the spot.
When to start, and when to revise
Getting the timing right on development
The conceptual cable routing layout belongs at the end of FEED or the start of detail design when the equipment arrangement is reasonably stable and an electrical load list exists, but before other disciplines have committed to designs that will constrain your routing options. Start earlier than that and you’ll likely do the work twice. Start later and you’ll be making routing decisions that should have been made weeks ago, under time pressure, without the benefit of multi-discipline coordination.
The detailed cable routing design and cable schedule need to be complete before you issue cables for procurement. If you’re ordering cable without finalised routing, you’re guessing at lengths. On a large project, those guesses cost real money. IFC drawings should be with the contractor four to six weeks before cable installation is scheduled to begin and not the week before.
When the routing design needs to be revised
Cable routing drawings are live documents. Revise them when:
- Equipment moves — even a small shift in pump position changes cable lengths and may change the tray route entirely.
- Scope is added — new instruments, additional drives, communication infrastructure added mid-project all need to be routed, added to the schedule, and drawn.
- A site clash is resolved — if a tray route has to move to clear a pipe, the drawing moves with it. Field changes that never make it back to the master drawing are how as-built discrepancies are born.
- Standards change — a code revision during a long project warrants a formal review, not a quiet assumption that the existing design is still compliant.
The as-built drawing is the final revision. It should reflect what was installed, not what was planned. Produce it while the installation team can still answer questions, not six months later.
Software for cable routing design — an honest view
| Tool | Description |
| AutoCAD Electrical | It produces solid wire routing diagrams without a huge setup cost. Not glamorous, but reliable |
| EPLAN Electric P8 | Excellent for dense control panel work and complex cable management. |
| AVEVA E3D | The standard on large EPC and offshore projects where electrical, piping, and structure all live in the same 3D model. |
| Bentley OpenPlant / BRCM | Strong where the rest of the engineering is already in the Bentley ecosystem. P&ID and electrical integration is genuinely useful. |
| Revit MEP | The right choice for commercial building structured cabling, especially when the architectural and MEP models are already in Revit. |
| draw.io / Visio | Perfectly adequate for routing philosophy drawings that need client sign-off. |
| CADISON E&I Designer | A Credible mid-market option with decent template libraries |
One thing worth saying plainly: the tool is secondary to the process. We’ve seen excellent cable routing produced in AutoCAD by engineers who knew what they were doing, and we’ve seen expensive 3D models that were impressive to look at but couldn’t be used to answer a basic question about a cable route. The software doesn’t make the decisions. The engineer does.
Who designs it, and who approves it
The design side
The cable routing layout is led by an Electrical Engineer or an Instrumentation and Controls Engineer, depending on the scope. That person makes the routing decisions which paths, which segregation strategy, which standards apply, where the junction boxes go. CAD designers and 3D modellers execute those decisions in the chosen software. They are not the ones choosing the routing philosophy.
On larger projects, a Discipline Coordinator manages the interface between the electrical team and the structural, piping, and HVAC groups. Tray routes that haven’t been coordinated with everything else in the model are the source of most site clashes. The Coordinator’s job is to catch them before they reach site.
The approval side
Before any cable routing drawing is issued for construction, it goes through a formal review. The Lead Electrical Engineer signs off that the design is correct and code compliant. The Project Manager or Discipline Lead confirms it is within scope and on schedule. The Client’s Owner’s Engineer issues the IFC stamp the formal instruction to the contractor that this drawing is approved for installation.
On offshore projects, in hazardous areas, or anywhere a third-party certification body is involved their review and approval is required before installation can start.
Sectors we work in
The Engineering principles of cable routing are consistent. The standards, the environmental conditions, and the project constraints vary considerably. Here’s where we have direct experience.
| Oil & Gas — Onshore & Offshore Hazardous area classification, Ex-rated cable selection, NORSOK and API compliance, FPSO topsides and jacket layouts | Power Generation & Utilities HV and LV routing, cable tunnel and trench design, substation cable layouts, solar and wind farm cabling. |
| Petrochemical & Refinery High cable density, multi-discipline 3D coordination, ATEX zone routing, large-scale EPC delivery | Commercial & Office Buildings Structured cabling design, TIA-568 and ISO 11801 compliance, data and voice infrastructure, fit-out documentation. |
| Manufacturing & Heavy Industry Machine cable routing, control panel wire layouts, drag chain design, skid package documentation | Pharmaceutical & Life Sciences GMP-compliant layouts, clean room cable management, validation-ready drawings and schedules. |
Talk to us about your project
Cable routing layout is much harder to fix after the fact than to get right from the start. If you have a project coming up at FEED, mid-design, or heading into construction and you want a second opinion on the routing strategy or a team to deliver the full design package, we’re happy to talk through what that looks like. No sales pitch. Just a conversation about what your project actually needs.
Frequently Asked Questions
Start with the plot plan and mark your major sources and loads — switchrooms, MCCs, field panels, and the equipment they serve. Draw the shortest logical path between them, then look at what’s in the way: pipe racks, structural steel, buildings, roads, HVAC runs, anything that might block or constrain a tray route. Adjust. Then define your segregation boundaries — which routes carry power, which carry instrumentation, where they need to stay apart and by how much. Mark your intermediate junction box positions to break long runs. What you end up with is the primary route map — the conceptual cable routing layout. Do this at drawing stage before committing to detailed CAD. A line on a plot plan sketch takes seconds to move. A modelled tray run does not.
The biggest single lever is junction box positioning. A well-placed marshalling box in the middle of a dense instrument cluster can shorten a dozen cable runs significantly. Beyond that: share tray routes where segregation rules allow, avoid unnecessary direction changes (every bend costs material and installation time), and review the longest cable runs specifically — it is surprisingly common for a route that looks reasonable on a plot plan to add 30% in length navigating around obstructions in 3D. In a 3D model, check automated length outputs on critical long cables early, while equipment positions can still be adjusted.
Because the decisions you make at the conceptual stage are cheap to change and expensive to change later. If you establish the primary tray routes during FEED, structural engineers can design supports against them, civil engineers can plan cable trenches and ducts, and procurement can order tray material. If you skip the conceptual stage, those same decisions get made mid-detail-design — after other disciplines have already progressed based on assumptions that may turn out to be wrong. Rerouting a main tray at that point is not a drawing change. It’s a delay.
At the conceptual stage, draw.io is fast, and entirely adequate for a routing schematic that needs client sign-off. For detailed wire routing diagrams on industrial projects, AutoCAD Electrical is the most widely accepted. For large EPC projects where electrical has to live in the same 3D model as piping and structure, AVEVA E3D or Bentley OpenPlant is the right environment. For commercial building structured cabling in an existing BIM project, Revit MEP
Along the structural frame wherever possible, in wire ducts or conduit where protection is needed. Power cables and signal cables on separate paths — opposite sides of the frame is ideal. For moving axes, cables go into drag chains or cable carriers rated for continuous flexing — not standard cables in a loose bundle. Every cable should be supported at regular intervals with no free-hanging spans. Minimum bend radius maintained at every bend, and nothing positioned where it can be caught by normal machine operation or interfere with maintenance access. A wire routing diagram showing all of this should exist before the machine is wired, not after.