Capability
High-temperature silicone cable assemblies
Silicone stays supple from −60 °C to 200 °C and survives millions of bend cycles, which is why it wires ovens, heaters, moulding lines and robot joints. This page says where we use it, where we do not, and what we reach for instead — because the wrong jacket in the right place is a field failure with a long lead time.
Where silicone is the right answer
Two properties do the work: it does not harden with heat, and it does not work-harden with flexing. Most other jackets fail on one or the other.
- Oven, heater and appliance wiring at 200 °C continuous — still strippable after years pressed against a hot frame
- High-strand battery links for inverters and energy storage, flexible enough to route inside a tight enclosure
- Twisted pair for robot joints and end-effectors, rated for millions of bend cycles inside a drag chain
- Screened multicore for encoder and sensor leads on moving axes, where a PVC jacket cracks at the bend point
- Machines that run hot — moulding, heat-sealing and drying lines — where PVC softens against the frame
- Circuits that must stay insulated while hot and halogen-free: silicone chars to an insulating ash rather than feeding the fire
Where it is not — and what we use instead
Silicone swells in oil and cutting fluid, its soft jacket cuts easily on an edge, and it stops at 200 °C. Each of those has a better answer, and specifying silicone anyway is how a harness comes back.
- Oil, coolant, fuel
- PUR. Tough against abrasion and machine fluids, and the standard jacket for a drag chain that also sees coolant. Silicone in cutting fluid swells and splits.
- Above 200 °C
- PTFE, to 260 °C continuous, with a thinner wall and full chemical inertness — the choice for sensor, heater and thermocouple wiring inside the hot zone.
- Abrasion and edges
- Silicone where it flexes, with sleeving, conduit or a grommet at every point it passes a metal edge. A silicone jacket without edge protection is a wear point.
- A formal fire class
- LSZH where the specification names a smoke and halogen class (EN 45545, enclosed public spaces). Silicone is halogen-free and low-smoke, but it is not what the certificate names.
Construction details that matter at temperature
The wire’s rating is only the start. A 200 °C wire crimped into a contact rated for 105 °C, in a housing rated for 105 °C, is a 105 °C harness. So every part of a high-temperature assembly is specified to the same figure: contacts with plating and spring temper rated for the heat, housings in a high-temperature moulding, and heat-shrink and markers that will still be legible and still be attached after the first thousand hours.
Conductors are high strand count where the assembly flexes, because conductor fatigue — not jacket failure — is what ends the life of a flexing cable. The termination is strain-relieved so the bend happens in the cable, never at the crimp.
Tell us the continuous temperature and the peak, separately. A jacket that is fine at 180 °C continuous may not survive a 240 °C cleaning cycle, and the drawing rarely says which one the figure is.
Specification summary
- Silicone
- −60 °C to 200 °C continuous; high-flex; halogen-free. Single core, screened multicore and twisted pair.
- PTFE
- 260 °C continuous; thin wall; chemically inert. Single core, twisted pair, screened multipair, coaxial and ribbon.
- Terminations
- Crimp contacts rated for the temperature; ring and lug terminals for battery links; RF connectors on PTFE-dielectric coaxial
- Standards
- IPC/WHMA-A-620 workmanship; UL 758 AWM wire where the end product is itself UL listed; RoHS and REACH declarations on request
- Testing
- Crimp height and pull force; 100% continuity with short and mis-wire checks; insulation resistance and hipot where the circuit carries mains
Typical applications
- Robotics — joint and end-effector wiring in continuous-flex silicone twisted pair
- Lighting and LED — driver leads where fixture temperatures run high
- Medical and laboratory devices — silicone and PTFE where sterilisation cycles are involved
- Electric vehicles and energy storage — silicone high-strand battery links and BMS sense looms
- Industrial ovens, moulding and heat-sealing lines — screened multicore in silicone for sensors and drives running hot
- Test cells and process instruments — PTFE single core, twisted pair and multipair inside the hot zone
- Defence and aerospace ground equipment — PTFE insulation with a first-article report on every new part number
What to send for a quote
For a high-temperature assembly, three facts matter more than the rest: the continuous and peak temperatures, whether the assembly flexes and how often, and which fluids it will see. With those, and the connector callouts and lengths, we can specify the construction and price it. Anything else on the list below helps.
- Drawing or sketchEven a hand sketch with lengths marked is enough to start
- Wire list or scheduleFrom-to, circuit numbers, gauge and colour if you have it
- Connector part numbersHousing and contact numbers, or a photo of the mating part
- Cable specificationType, gauge, core count, screening, temperature rating
- Lengths and toleranceOverall length, branch lengths, breakout positions
- Quantity and schedulePrototype count, first batch and expected annual volume
- EnvironmentTemperature, flexing, moisture, chemicals, vibration
- Approvals requiredAny flammability, smoke or sector-specific requirement
We quote in INR, EUR or USD and ship under EXW, FCA, FOB, CIF or DAP (Incoterms® 2020), with the rule fixed on the quotation.
Questions we are asked
- How hot can a silicone cable assembly run?
- 200 °C continuous, and it stays flexible down to −60 °C. Above 200 °C we move to PTFE, which is rated to 260 °C continuous, and the contacts and housing have to be rated for the same figure or the assembly is not.
- Is silicone suitable where there is oil or coolant?
- No. Silicone swells in oil, fuel and cutting fluid. Where the assembly sees machine fluids we specify PUR, which is abrasion- and oil-resistant, or PTFE where the temperature also demands it.
- Silicone or PTFE — which should the drawing call for?
- Silicone where the assembly flexes or the priority is a supple jacket at up to 200 °C. PTFE where the temperature is higher, the wall has to be thin, or the cable meets chemicals. PTFE has poor flex life in a chain, so it is the wrong answer for a moving axis however hot it runs.
- Can you build silicone assemblies for enclosed spaces where halogen-free is required?
- Yes. Silicone is halogen-free and low-smoke, and chars to an insulating ash. Where a specification names a formal class — EN 45545 for rail, for example — we build in LSZH, because that is the construction the certificate refers to.
- Do you build drag-chain and continuous-flex assemblies?
- Yes. Silicone twisted pair and screened multicore where the axis runs hot or the priority is flex life; PUR where the chain also sees coolant and abrasion. In both cases the conductors are high strand count and the termination is strain-relieved so the bend never reaches the crimp.
- Do you supply outside India?
- Yes. We quote in INR, EUR or USD, ship under EXW, FCA, FOB, CIF or DAP (Incoterms® 2020), and issue RoHS and REACH declarations for the parts used.