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EMC

CISPR 25:2016 / 2021 CEV Limits

Conducted Emission – Voltage Method (The 2021 voltage method limits are identical to those of 2016)

This table compiles the Conducted Emission (CEV) voltage method limits (corresponding to Table 5/6) for automotive components per CISPR 25, including complete data for Class 1-5, suitable for EMC pre-compliance and certification reference.

Limit Visualization Curve
Class:
Filter Table by Class:
Levels in dB(µV). Scroll horizontally to view more.
Service / Band
Frequency MHz
Class 5 Class 4 Class 3 Class 2 Class 1
Peak QP Avg Peak QP Avg Peak QP Avg Peak QP Avg Peak QP Avg
BROADCAST
LW 0.15 to 0.30 70 57 50 80 67 60 90 77 70 100 87 80 110 97 90
MW 0.53 to 1.8 54 41 34 62 49 42 70 57 50 78 65 58 86 73 66
SW 5.9 to 6.2 53 40 33 59 46 39 65 52 45 71 58 51 77 64 57
FM 76 to 108 38 25 18 44 31 24 50 37 30 56 43 36 62 49 42
TV Band I 41 to 88 34 - 24 40 - 30 46 - 36 52 - 42 58 - 48
MOBILE SERVICES
CB 26 to 28 44 31 24 50 37 30 56 43 36 62 49 42 68 55 48
VHF 30 to 54 44 31 24 50 37 30 56 43 36 62 49 42 68 55 48
VHF 68 to 87 38 25 18 44 31 24 50 37 30 56 43 36 62 49 42

Need to convert units for this standard?

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Test Setup & Technical Overview

Detailed engineering guide for Conducted Emissions (CEV) by Voltage Method / LISN Method

Technical Overview: Voltage Method vs. Current Probe

The voltage method (CEV) and current probe method (CEC) are complementary techniques for assessing conducted emissions on power supply lines. While the current probe method (CEC) measures the noise currents, the voltage method (CEV) directly measures the disturbance voltage at the terminals of the Equipment Under Test (EUT).

The LISN/AN (Line Impedance Stabilization Network) acts as a standardized interface, providing a defined RF impedance. CEV is the primary regulatory compliance method for ensuring that component-level emissions do not conduct back into the vehicle's low-voltage electrical distribution system, whereas CEC is more focused on harness radiation characteristics.

Test Configuration & LISN Isolation

For a valid CEV measurement, the EUT is placed on a non-conductive, low-dielectric support 50 mm above the ground plane. A Line Impedance Stabilization Network (LISN) or Artificial Network (AN) is inserted in the power lines.

The LISN isolates the EUT and the measuring receiver from RF noise present on the external power supply, while offering a stable 50 Ω impedance for high-frequency signals. The wiring harness between the EUT and the LISN must be kept to 200 mm.

Interpretation of Limits (Class 1-5)

CISPR 25 specifies five limit classes to accommodate different vehicle environments and installation configurations:

  • Class 5: The most stringent class, typically mandated by OEMs for safety-critical components (ADAS, steering, braking) or devices located near sensitive radio antennas.
  • Class 4 & 3: Applied to standard body electronics, powertrain control units, and infotainment displays.
  • Class 2 & 1: The least severe limits, reserved for simple, transient, or non-critical loads (e.g., seat adjusters, window motors) that present minimal risk to the vehicle's RF receivers.

How to read the CISPR 25 CEV reference

User task

Use CEV to compare RF disturbance voltage at the applicable artificial network or LISN connection of a vehicle component. The page keeps Class 1–5, edition and receiver context visible rather than treating every conducted result as the same method.

Choose before comparing

Choose the 2016 or 2021 edition and the class before reading a margin. The cited 2016 reference context reaches 150 kHz–2500 MHz and the 2021 context reaches 150 kHz–5925 MHz; the visible rows are selected service bands rather than a continuous sweep. CEV is a dBµV voltage method at the LISN/AN; the applicable receiver band and RBW, including the 9 kHz rows shown in the 2021 data, follow the selected edition. No radiated distance applies.

What the displayed rows mean

Method and unit
CEV is the conducted voltage / LISN method and uses dBµV; it is not interchangeable with CEC current in dBµA.
Edition and RBW
The cited 2016 reference context reaches 150 kHz–2500 MHz and the 2021 context reaches 150 kHz–5925 MHz; the visible rows are selected service bands, not a continuous sweep. The data sets are selected independently, and the 2021 view exposes 9 kHz RBW entries where they are encoded.
Port and network
The EUT, harness, artificial network and detector settings must match the selected test plan; no antenna distance is attached to a CEV row.

Common misread

A LISN voltage value is not a current-probe value and is not a radiated field-strength result. Preserve the artificial-network configuration, edition, class, detector and RBW when using the table.

Reference boundary

EMCCalc summarizes public IEC Webstore records for the two editions and the encoded CEV data. The applicable purchased edition and complete vehicle-component test plan remain authoritative; protected standard text is not copied.

Content review date:

Source and verification

Primary source

IEC Webstore — CISPR 25:2016 Edition 4.0; 2016 voltage-method table set

IEC Webstore — CISPR 25:2021 Edition 5.0; 2021 voltage-method table set and RBW values

Applicability
Vehicle electronic/electrical components and modules for protection of on-board receivers; Class 1–5 data are selectable.
Read this limit with
  • Voltage method using the applicable LISN/AN
  • dBµV
  • Receiver bands and RBW are shown for the selected edition where encoded
  • EUT, harness, artificial network, and detector settings must follow the selected edition and test plan
  • No radiated-test distance applies
Last source-link and context review
Verification method
The source link, edition/section locator, and measurement context were reviewed against the values shown here. This reference is not a formal conformity assessment or certification.

Engineering reading

Choose the applicable vehicle/component scope, standard edition, class, method, receiver setting, and full test plan before using this lookup for a compliance decision.