How to calculate cable outer diameter?
No simple universal formula. Estimate by: lay-up diameter of cores (geometry), plus tape (0.05-0.1mm), shield (braid ~0.3-0.8mm), sheath (1.0-1.8mm per standards).
Best to refer to manufacturer’s datasheet or measure.
What are the types of cable shielding? Pros and cons?
Foil shield: 100% coverage, good for high frequency, poor flex life, easily torn.
Braid shield: 60-95% coverage, good flexibility, good for low frequency, higher cost.
Spiral/serve shield: intermediate.
Foil + braid: double shielding, best performance.
How to simply test if a cable is halogen-free?
Simple method: wrap a small piece of insulation on a copper wire and burn with an alcohol flame. Green flame indicates halogen (chlorine).
Lab test per IEC 60754 for accuracy. Halogen-free materials burn with little smoke and no green flame.
What does “halogen-free” mean for cables? Why is it important?
Halogen-free means the cable materials contain no fluorine, chlorine, bromine, iodine, astatine. Burning produces no corrosive/toxic gases like HCl, HBr, HF.
Critical for human safety and electronics in confined spaces (aircraft, subways, data centers).
Per IEC 60754, ≤2 mg/g acid gas release qualifies as halogen-free.
What do smoke density classes s1, s2, s3 mean for cables?
Per EN 50399 or IEC 61034, measure light transmittance during burning.
- s1: ≥80% (lowest smoke)
- s2: 60-80%
- s3: <60% (highest smoke)
Hospitals, subways require s1. CPR class often combined, e.g., Cca-s1.
Source: EN 50399 / IEC 61034.
What does “UL AWM” mean on a cable label?
AWM stands for Appliance Wiring Material, a UL certification category for internal wiring of electronic devices and appliances.
It specifies temperature rating (e.g., 105°C), voltage (e.g., 300V), gauge (e.g., AWG 18), and flame rating (e.g., VW-1).
Not for building wiring, only for internal appliance use.
inquiry
