Control Cable Selection Guide: Shielded vs Unshielded, Braid vs Foil
Created on 06.09
If you are connecting sensors, PLCs, motors, or instrumentation devices, you need control cable — not power cable.
But control cable comes in many variations. Unshielded. Foil shielded. Braid shielded. With drain wire. Without drain wire.
This guide explains the differences and helps you choose the right one for your application.
First: What Makes a Control Cable Different from Power Cable?
Power cable does one thing: carry electricity from point A to point B. Voltage is high. Current is high. Signal quality does not matter.
Control cable does something different: carry low-voltage signals (24V, 110V, 230V) between devices. Signal integrity matters. Interference is a problem.
Feature | Power Cable | Control Cable |
Voltage | High (0.6/1kV and up) | Low (300/500V typical) |
Conductor size | Large (10mm² and up) | Small (0.5mm² to 6mm²) |
Number of cores | Few (1-5 cores) | Many (2 to 100 cores) |
Shielding | Rarely | Often |
Signal integrity | Not important | Critical |
If your cable connects to a PLC, VFD, sensor, or instrument — you probably need control cable.
Shielded vs Unshielded: When to Use Which
Shielding is a conductive layer (copper tape, aluminum foil, or copper braid) wrapped around the insulated conductors. Its job is to block electrical noise (electromagnetic interference, or EMI).
Unshielded control cable (CY or LiYY type)
- No shielding layer
- Lower cost
- Easier to terminate
- Suitable for clean electrical environments (no nearby VFDs, motors, or high-voltage cables)
Shielded control cable (CY or LiYCY type)
- Has shielding + often a drain wire
- Blocks external electrical noise
- Higher cost
- Slightly more difficult to terminate
- Suitable for industrial environments with VFDs, motors, relays, or parallel cable runs
Environment | Recommendation |
Clean office / control room | Unshielded is fine |
Panel wiring with no nearby VFDs | Unshielded is fine |
Running parallel to power cables | Shielded required |
Near VFD output cables | Shielded required |
Near welding equipment | Shielded required |
Signal cables (4-20mA, thermocouple) | Shielded required |
Rule of thumb: If you are not sure whether you need shielding — choose shielded. The cost difference is small compared to troubleshooting noise problems later.
Braid Shield vs Foil Shield: What is the Difference?
Both types block interference, but they work differently.
Foil Shield (Aluminum + Polyester Tape)
Property | Foil Shield |
Construction | Thin aluminum layer bonded to polyester film |
Coverage | 100% (no gaps) |
Flexibility | Poor — can crack with repeated bending |
Termination | Requires drain wire (cannot solder to foil) |
Low-frequency noise | Good |
High-frequency noise | Excellent |
Cost | Lower |
Braid Shield (Copper Wire Mesh)
Property | Braid Shield |
Construction | Copper wires woven into a mesh |
Coverage | 70-95% (small gaps remain) |
Flexibility | Excellent — withstands repeated flexing |
Termination | Can be soldered or clamped |
Low-frequency noise | Excellent |
High-frequency noise | Good (less than foil) |
Cost | Higher |
When to choose which:
Application | Best Shield |
Fixed installation (cable does not move) | Foil shield (100% coverage, lower cost) |
Robotic / moving application | Braid shield (flexibility matters more) |
VFD output (high-frequency noise) | Foil shield or combination (foil + braid) |
General industrial (some movement) | Braid shield |
Sensitive instrumentation | Combination shield (foil + braid) |
For most general industrial control applications, braid shield is the safer choice. It handles installation bending better and is more durable.
Core Identification: Colors vs Numbers
Contact
Looking for a reliable cable manufacturer? Send us your requirements today. Our export sales team will reply within 12 business hours with a professional quotation.
To help us prepare an accurate quotation, you may reply to our email with:
• Cable Type • Voltage • Conductor Size
• Quantity • Destination Country
Need a quotation urgently? Contact us directly via WhatsApp:+86 15838292863