By TEBAOFLEX Jyen. Originally published on December 5, 2025.
A festoon system carries power and signals in hanging loops supported by moving trolleys. Choosing between NGFLGÖU-type flat rubber cable, screened NGFLCGÖU-type constructions, KYFLCY-type screened PVC cable and a PUR alternative requires both a cable specification and a compatible trolley layout. The family name is not a complete statement of temperature, bend radius or EMC performance.
Select the cable and trolley system together
Conductix describes festoon cables as selected and validated for their trolley application. Both flat and round arrangements exist. A cable being flexible, screened or suitable for an energy chain does not by itself qualify it for every festoon route; repeated bending direction, loop movement and clamping need to match the design.
Conductix-Wampfler — cables for festoon systems
Compare the construction families
- Flat rubber construction: check the specified insulation and sheath compounds, voltage, conductor arrangement and moving-temperature range. Do not infer every rubber cable has the same cold-flex rating.
- Screened flat rubber construction: identify whether screens are applied to individual cores, groups or the whole assembly, and verify the required shielding and repeated-flex performance.
- Screened flat PVC construction: confirm the actual compound’s movement and temperature limits, environmental resistance and permitted bending plane. “PVC” alone does not define a universal outdoor prohibition or a specific minimum temperature.
- PUR alternatives: check the complete construction and approved application. A polyurethane jacket does not establish the insulation temperature rating, energy-chain endurance, smoke performance or resistance to every chemical.
Thickness, width and bending plane
For a flat cable, bending behavior depends on its orientation and construction. A manufacturer may express the allowed radius as a multiple of cable thickness for the intended bending plane. That instruction cannot be transferred to edgewise bending or to a different flat cable, and must not be confused with a diameter-based rule for a round cable.
For illustration only, if a particular approved design required a radius of 5h and its specified thickness were 18.5 mm, the arithmetic would give 92.5 mm. The assumed 5h factor is not a universal rating for NGFLGÖU, and this example does not approve a trolley saddle. Check the exact cable and support geometry.
Cable stacking: do not apply a universal bottom-heavy rule
Conductix’s I-beam festoon engineering guidance places larger power cables at the top of the documented flat-cable package, supporting heat dissipation and the intended load distribution. This contradicts a blanket instruction to put every heavy power cable against the bottom saddle. Use the approved arrangement for the actual trolley and clamp system; different supports and clamps need their own instructions.
Conductix-Wampfler — I-beam festoon engineering guidelines
Check package stability, clamping contact, symmetry about the trolley and individual cable lengths. Do not add arbitrary side clearance or allow cables to slide in a clamp intended to hold them. Equally, do not rigidly restrain a layer that the specified clamp arrangement is designed to leave movable.
Loop depth and ordered cable length
Start with the usable travel length, available storage zone, trolley dimensions, number of loops, allowable loop depth, towing arrangement and termination tails. Confirm maximum extension and parked configuration, including movement clearances and whether different layers need different lengths.
A simple formula based only on loop depth and a fixed 1.15 slack factor cannot establish a complete layout. It omits support spacing, trolley accumulation, cable and clamp geometry and the designed extension limit. Obtain a layout drawing and cable cutting schedule for the actual system before ordering or cutting cable.
EMC requires more than braid coverage
Where inverter motor power and sensitive signals share a moving route, follow the drive and control-system manufacturers’ EMC requirements. Consider separation, shield continuity, termination geometry and bonding across the complete route. A screened cable does not guarantee zero capacitive coupling or eliminate every nuisance trip.
Screen design also has to survive the intended movement. Do not assume that every foil screen fails after a fixed cycle count, or that every overall braid fails immediately on a flat cable. Request qualification evidence for the exact construction and duty.
Halogen-free is not the same claim as low smoke
A halogen-free material claim does not establish the smoke emission, flame propagation or circuit integrity of the finished cable. State the required tests and acceptance criteria separately. Chemical resistance must identify the actual fluid, concentration, temperature and exposure duration; a general jacket-material description is insufficient.
IEC 60754-1 — halogen acid gas testing of cable materials
IEC 61034-2 — smoke density testing of cables
Acceptance checklist — no batch results are claimed
- Construction drawing and voltage/conductor identification, with dimensions and tolerances.
- Documented moving-temperature range, bending plane, minimum radius and application qualification.
- Trolley layout, package arrangement, clamp instructions and cutting schedule.
- Electrical and shielding requirements agreed for the drive and signal circuits.
- Relevant electrical, flexing and environmental test evidence with conditions and criteria recorded; distinguish product qualification from routine checks on a supplied length.
Before replacing a festoon pack
Inspect the existing route for incorrect loop length, damaged supports, seized trolleys, unsuitable clamping, contamination and misalignment as well as cable damage. Replacing only the cable may leave the cause of damage unchanged. Any revised package should be checked against the equipment manufacturer’s requirements before service.
For a project-specific datasheet and an agreed inspection plan, contact TEBAOFLEX. WhatsApp: +86 185 9591 3361. Provide the equipment duty, cable route and applicable project specifications.