DEC 5 | 20 mH Symmetrical Decoupling

DEC 5 - 6.6 kV Decoupling Network for Symmetrical Lines

20 mH current-compensated inductors for symmetrical signal-line testing.

The Haefely DEC 5 separates auxiliary equipment from an EUT during transient immunity testing on unshielded symmetrical lines. It supports up to four wires and impulses up to 6.6 kV, using 20 mh current-compensated inductors; two inductors with two coils each. Coupling is performed by a separate network, allowing protection and decoupling to match the signal circuit.

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DEC 5 Datasheet V2026.06

SPECIFICATIONS

HAEFELY EMC ACCESSORIES

DEC 5 - 6.6 kV Decoupling Network for Symmetrical Lines

20 mH current-compensated inductors for symmetrical signal-line testing.

Overview and application

Manual protection selection makes the connected protection elements visible.
The decoupling network does not generate or couple the test impulse; use it with a suitable coupling network and generator.
Select EUT voltage, current and signal bandwidth together; the decoupling path can affect normal communication.
Manufacturer-listed coupling networks: PCD 120, PCD 121 and PCD 122.

Technical specifications

Specification	Details
Function	Decoupling and auxiliary-equipment protection; coupling supplied separately
Line type / capacity	Unshielded symmetrical data and control lines; up to 4 wires
Supported impulse shapes	1.2/50 us - 8/20 us combination wave; 100 kHz ring wave; 10/700 us - 5/320 us telecom wave
Maximum impulse amplitude	6.6 kV peak
Decoupling elements	20 mH current-compensated inductors; two inductors with two coils each
Protection elements	Gas arrestors and avalanche breakdown diodes (ABDs)
Protection selection	Manual; operation without protection elements is also possible
EUT voltage with gas arrestors	Maximum 72 V DC or 50 V AC RMS
EUT voltage with ABDs	Maximum 144 V DC or 100 V AC RMS
Maximum EUT line current	1 A
EUT signal bandwidth	Up to some 100 kHz / some 100 kBaud
Connections	Safety banana sockets
Dimensions (W x D x H)	300 x 160 x 200 mm (11.8 x 6.3 x 7.9 in)
Weight	Approximately 9 kg net (19.8 lb)

Included components

DEC 5 decoupling network
Cable set
Four short-circuit bridges
User manual

Generator, EUT, auxiliary equipment and other coupling/decoupling networks are separate system equipment unless explicitly included above.

Standards and system configuration

IEC/EN 61000-4-5 Edition 2 Figure 14; Edition 3 Figure 10.
IEC/EN 61000-4-12 Edition 2 Figure 12; Edition 3 Figure 9.
ITU K.44:2003 Figures A.5-1 and A.6.1-1 through A.6.1-5.

Compare data-line coupling and decoupling networks

Product	Function	Signal circuit	Test waveform	Key ratings
PCD 121	Coupling	Symmetrical; 2 pairs / 4 wires	Combination wave	6.6 kV; selectable gas arrestor / ABD coupling
PCD 126A	Coupling	4 wires; asymmetrical surge; symmetrical or asymmetrical ring wave	Combination wave; 100 kHz ring wave	6.6 kV; capacitors, ABDs, gas arrestors or direct
DEC 5	Decoupling	Symmetrical; 4 wires	Combination, telecom and ring wave	6.6 kV; 20 mH compensated; 1 A
DEC 6	Decoupling	Symmetrical; 4 wires	Combination, telecom and ring wave	6.6 kV; 200 ohm; 0.1 A
DEC 7	Decoupling	Asymmetrical; 4 wires	Combination and ring wave	6.6 kV; 20 mH uncompensated; 1.5 A
PCD-1000-4	Coupling + decoupling	Balanced Ethernet; 1 / 2 / 4 pairs; 1000Base-T	Combination wave	4 kV / 150 A surge; 65 V DC / 1 A line; IEEE 802.3af PoE

Combination wave: 1.2/50 us voltage and 8/20 us current. Telecom wave: 10/700 us voltage and 5/320 us current. Ratings depend on the selected coupling/protection elements; review each product specification before configuring the system.

PCD 121 and PCD 126A provide coupling only. DEC 5, DEC 6 and DEC 7 provide decoupling/protection only. PCD-1000-4 combines both functions for high-speed Ethernet. IP4B is an EFT/burst clamp and is intentionally excluded from this matrix.