> Pepperl+Fuchs Z928 Zener barrier for Ex sounder lines
> Source: https://pap.fi/en/tuote/zener-barrier-z928-palokellot/
> Full site in machine-readable form (in Finnish): https://pap.fi/llms-full.txt
> Pages in English: https://pap.fi/llms.txt

# Pepperl+Fuchs Z928 Zener barrier for fire bells

Product code 42076

Single-channel Zener barrier (Pepperl+Fuchs Z928) that separates the lines of intrinsically safe fire bells and sounders located in Ex areas from the safe area.

-   1 channel, AC version, series resistance max. 327 Ω
-   Ex ia output parameters: Uo 28 V, Io 93 mA, Po 650 mW
-   ATEX BAS 01 ATEX 7005, IECEx BAS 09.0142
-   Field devices for zones 0, 1 and 2
-   Fuse 50 mA, working voltage 26 V (10 µA)
-   12.5 mm wide, for 35 mm DIN rail

## Product description

Pepperl+Fuchs Z928 is a single-channel Zener barrier that prevents excessive energy from passing from the safe area into a hazardous area. In this product it is used on the alarm device lines of Ex areas: the alarm output of the fire alarm control panel is connected to the safe-side terminals of the barrier, and intrinsically safe fire bells or sounders to the Ex-side terminals.

### Operation

The Zener diodes of the barrier are reverse-biased. In normal operation their breakdown voltage is not reached, but if a fault occurs on the safe side and the voltage rises, the diodes start to conduct and the 50 mA fuse blows. In the AC version the diodes are connected back to back, so the barrier is suitable for both AC and DC signals. The nominal resistance is 300 Ω and the series resistance at most 327 Ω.

### Approvals and Ex values

The barrier has the ATEX type-examination certificate BAS 01 ATEX 7005 and IECEx certification, as well as FM and UL approvals. The output values are Uo 28 V, Io 93 mA and Po 650 mW, and the field devices can be located in zones 0, 1 and 2. The barrier itself can be installed in zone 2 (Ex nA / Ex ec). For example, the datasheets of the E2S IS-A105N and IS-mA1 alarm devices give permitted input values of 28 V / 93 mA / 660 mW. The system as a whole must always be verified against the Ex parameters of the devices and the cable.

### Installation

The barrier is mounted on a 35 mm DIN rail (EN 60715), and the module width is 12.5 mm. The Ex-side conductors are connected to terminals 1–2 and the safe-side conductors to terminals 7–8. Conductors may be at most 2 × 2.5 mm².

## Technical data

- **Product code:** 42076
- **Manufacturer:** Pepperl+Fuchs
- **Product group:** Fire alarm systems › Field devices › Alarm devices
- **Dimensions:** 12.5 × 115 × 116 mm (W × H × D)
- **Weight:** Approx. 150 g
- **IP rating:** IP20
- **Operating temperature:** −20…+60 °C
- **Humidity:** Max. 75% RH, non-condensing
- **Channels:** 1 (AC version)
- **Resistance:** Nominal 300 Ω, series resistance max. 327 Ω
- **Fuse:** 50 mA
- **Operating voltage:** Working voltage 26 V (10 µA), supply loop max. 26.3 V
- **Ex output parameters:** Uo 28 V, Io 93 mA, Po 650 mW; Um 250 V
- **ATEX classification:** II (1)GD, I (M1) \[Ex ia Ga\] IIC, \[Ex ia Da\] IIIC, \[Ex ia Ma\] I; II 3G Ex nA IIC T4 Gc
- **ATEX certificate:** BAS 01 ATEX 7005; TÜV 99 ATEX 1484 X
- **IECEx certificate:** IECEx BAS 09.0142, IECEx BAS 17.0091X
- **Connection:** Screw terminals, max. 2 × 2.5 mm²; Ex side 1–2, safe side 7–8
- **Mounting:** 35 mm DIN rail (EN 60715)
- **Standards:** EN IEC 60079-0, EN IEC 60079-11, EN IEC 60079-7; FM, UL (cULus)

## Documents

Original manufacturer documents (PDF).

### Technical datasheets

-   [Technical datasheet: Zener barrier Z928 for fire bells](https://pap.fi/liitteet/valmistajat/files__071857_eng.pdf) PDF · English · 676 kB

### Installation guides

-   [Installation guide (series): Pepperl+Fuchs Z-System Zener barriers](https://pap.fi/liitteet/valmistajat/files__tdoct0185j_eng.pdf) PDF · English · 1.2 MB

### Certificates and declarations

-   [EU declaration of conformity, no. DOC-0060G](https://pap.fi/liitteet/valmistajat/files__tdoc0060g_fin.pdf) PDF · multilingual · 187 kB