Double Aluminum Foil with PET Core (AL PET AL) for Shielding in Environmental Monitoring Cables
Double Aluminum Foil with PET Core (AL PET AL) for Shielding in Environmental Monitoring Cables
Environmental monitoring cables don't live in tidy lab conditions. They run along rivers, across farmland, inside pumping stations, on towers, and through outdoor cabinets-places where humidity, temperature swings, vibration, and electrical noise happen at the same time. From this field-first viewpoint, shielding is not just about passing an EMC test once; it's about keeping low-level sensor signals stable for years.
That's where Double Aluminum Foil with PET Core (AL PET AL) becomes a practical and reliable choice.
What AL PET AL actually is (in one line)
AL PET AL is a laminated tape structure: Aluminum foil + PET (polyester) film + Aluminum foil, applied helically or longitudinally around the cable core, usually with a drain wire to ensure a consistent ground connection.
Why environmental monitoring cables "feel" interference more than most
Many environmental sensors output weak signals (mV-level, µA-level, pulse trains, or low-voltage digital communication). In the field, common noise sources include:
- Variable frequency drives (VFD) in pumps and fans
- Solar inverters and switching power supplies
- Long parallel runs with power cables
- Lightning-induced surge environments and high E-field areas
- Radio transmitters near stations and towers
A shield that is electrically effective but mechanically fragile can fail silently-resulting in drifting readings, communication dropouts, or unstable baselines that look like "sensor issues" but are actually cable issues.
The distinctive advantage of AL PET AL: stability, not just shielding
1) Better continuity under bending and vibration
Single aluminum foil shields can crack over time if repeatedly flexed or exposed to vibration. The PET core acts like a mechanical backbone, improving tear resistance and helping the foil layers maintain integrity during installation and service.
Practical outcome: fewer micro-cracks → more consistent shielding over life, especially in outdoor runs and cabinet-to-sensor movement zones.
2) Stronger barrier behavior in humid, outdoor environments
Environmental monitoring often means condensation, wet conduits, and soil moisture. While the jacket is the primary moisture barrier, the shield layer also influences long-term stability. The PET layer reduces the chance of pinholes and handling damage, supporting more uniform coverage when the tape is wrapped.
Practical outcome: the shielding layer stays "whole" and less vulnerable to accidental nicks during stripping or pulling.
3) Improved high-frequency shielding performance
Foil shields are excellent for electric-field (E-field) and high-frequency interference. Using aluminum on both sides with a PET core helps maintain a uniform conductive surface and consistent overlap, which supports reliable attenuation of high-frequency noise.
Practical outcome: cleaner data signals near inverters, transmitters, and switching equipment.
Where AL PET AL fits best in environmental monitoring cable designs
AL PET AL is especially suitable for:
- Multi-pair signal cables (RS-485/Modbus sensor networks, pulse outputs)
- Low-level analog sensor lines (pH, ORP transmitters, turbidity, dissolved oxygen systems)
- Remote station wiring with long runs and mixed electrical infrastructure
- Hybrid cables carrying signal + low power (where coupling risk is higher)
If your environment also includes strong magnetic-field (H-field) interference (e.g., large motors very close), consider adding a braid or using foil + braid designs, because braid performs better for low-frequency magnetic fields.
design details customers should confirm (fast checklist)
When specifying AL PET AL shielding, confirm:
- Application type: individual pair shield, overall shield, or both
- Drain wire: tinned copper drain wire included (recommended for stable grounding)
- Coverage/overlap: shielding overlap and lay direction (affects consistency)
- Thickness of aluminum and PET: matched to flexibility and shielding needs
- Grounding method: single-point or multi-point grounding based on system design (avoid ground loops in sensitive analog systems)
A simple way to think about it
For environmental monitoring, AL PET AL is less about "maximum shielding on paper" and more about durable shielding that keeps working after years of pulling, bending, humidity, and maintenance cycles.