INDUSTRY COMPONENT

X-Capacitor (Line-to-Line)

X-capacitor for line-to-line EMI suppression in industrial EMC filters

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Component Specifications

Definition
An X-capacitor (also called line-to-line capacitor) is a safety-rated capacitor connected between live conductors (line-to-line or line-to-neutral) in electrical circuits. It suppresses differential-mode electromagnetic interference (EMI) by providing a low-impedance path for high-frequency noise currents to return to their source, preventing propagation through power lines. These capacitors must meet stringent safety standards due to their connection across AC mains.
Working Principle
Operates by capacitive reactance (Xc = 1/(2πfC)), which decreases with increasing frequency. At high frequencies (EMI range), the capacitor presents low impedance, shunting noise currents away from sensitive equipment. For differential-mode noise (between lines), X-capacitors provide a preferential path for noise currents to circulate locally rather than radiating or coupling into other circuits.
Materials
Metallized polypropylene film (MKP) or ceramic dielectric (Class X1/X2 rated), with self-healing properties; epoxy resin encapsulation; copper or tinned copper leads; flame-retardant plastic case (UL94 V-0 rated).
Technical Parameters
  • Tolerance ±10% to ±20%
  • Rated Voltage 250VAC to 440VAC (X2: 275VAC, X1: 760VAC)
  • Impulse Voltage 2.5kV to 4kV (X2), 4kV to 6kV (X1)
  • Leakage Current <0.5mA at 230VAC/50Hz
  • Safety Standards IEC 60384-14, UL 60384-14
  • Capacitance Range 0.001μF to 10μF
  • Temperature Range -40°C to +110°C
  • Dissipation Factor <0.001 at 1kHz
  • Insulation Resistance >10,000MΩ
Standards
IEC 60384-14, UL 60384-14, EN 60384-14, GB/T 6346.14

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for X-Capacitor (Line-to-Line).

X capacitor line-to-line capacitor EMI filter capacitor EMC filter component differential-mode noise suppression safety capacitor IEC 60384-14 industrial capacitor X-Capacitor (Line-to-Line) X-Capacitor (Line-to-Line) in Electrical Equipment Manufacturing

Parent Products

This component is used in the following industrial products

Input Filter (EMC Filter)

An electromagnetic compatibility filter designed to suppress conducted electromagnetic interference (EMI) entering or leaving a device via the DC input power lines.

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Engineering Analysis

Risks & Mitigation
  • Electrical shock if improperly rated or installed
  • Fire hazard from short-circuit failure
  • EMC non-compliance if underspecified
  • Reduced filter performance from aging or temperature drift
  • Leakage current exceeding safety limits
FMEA Triads
Trigger: Overvoltage transients (lightning, switching surges)
Failure: Dielectric breakdown leading to short-circuit
Mitigation: Use X1-class capacitors for high-impedance environments; incorporate surge protection devices (MOVs); design with derated voltage (e.g., 275VAC capacitor for 230VAC line)
Trigger: Thermal stress from high ambient temperature or ripple current
Failure: Capacitance drift or open-circuit failure
Mitigation: Select capacitors with high-temperature rating (≥105°C); ensure adequate ventilation; calculate and limit ripple current; use capacitors with low ESR
Trigger: Mechanical damage during assembly
Failure: Cracked casing leading to moisture ingress and corrosion
Mitigation: Follow manufacturer's mounting guidelines (lead bending radius); use strain relief; apply conformal coating in humid environments; implement visual inspection

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
Capacitance tolerance typically ±10% or ±20%; voltage derating of 20-50% recommended for reliability; leakage current must comply with IEC 60950-1 (<0.25mA for IT equipment)
Test Method
Safety testing per IEC 60384-14 (endurance, humidity, solderability); electrical testing (capacitance, dissipation factor, insulation resistance at 500VDC); impulse voltage test (10 pulses at specified voltage); flammability test (UL94 V-0)

Procurement Evaluation Criteria

Not customer reviews or live demand data. These dimensions support RFQ preparation and supplier evaluation.

Technical documentation
4/5
Manufacturing capability
4/5
Inspection readiness
5/5
Supplier transparency
3/5

These scores are example evaluation dimensions, not real customer ratings, country-specific buyer feedback, or live inquiry activity.

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Frequently Asked Questions

What is the difference between X and Y capacitors?

X-capacitors are connected line-to-line or line-to-neutral to suppress differential-mode EMI, while Y-capacitors are connected line-to-ground to suppress common-mode EMI. X-capacitors have lower safety requirements for failure (short-circuit risk), whereas Y-capacitors must fail open-circuit to prevent electric shock.

How do I select an X-capacitor for an EMC filter?

Consider: 1) Required capacitance based on EMI frequency spectrum, 2) AC mains voltage rating (e.g., 250VAC for 230V systems), 3) Safety class (X2 for general applications, X1 for high-impedance or industrial environments), 4) Temperature stability for operating conditions, and 5) Compliance with regional safety standards (IEC/UL/EN).

What happens if an X-capacitor fails?

X-capacitors are designed to fail safely, typically as a short-circuit initially, which may blow a fuse or trip a circuit breaker. Modern metallized film capacitors have self-healing properties that can clear minor faults, but sustained overvoltage or overheating can lead to permanent short-circuit or open-circuit failure, reducing EMI suppression effectiveness.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

Data Basis

CNFX manufacturer profiles, technical classification, publicly available product information, and ongoing plausibility checks.

Preliminary Technical Classification
This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

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