Protectowire Products

The WLM-System consists mainly of the following components:

1. WLM-Detector Wire

2. WLM-Interface-Modul

3. WLM-Accessories


WLM-Detector Wire

The WLM detector wire is available with different jacket materials and different alarm temperatures.  This makes it deployable for many different applications. Below we will introduce you to the different types of wires and to the main differences between them.

WLM is a resisitive contact device. The specific resistance is approx. 0,656 Ohm/m (1 ohm for every 5 feet).

All types have been tested for using them in environmental temperatures between -40°C/-40°F and the specific max. ambient temperature. The max. ambient temperature depends on the alarm temperature of the detector wire. Please have a look into the following table. WLM wire-family klein

Alarm Temperature Max. Ambient Temperature
 57°C/135°F, 68°C/155°F  38°C/100°F
 88°C/190°F 66°C/150°F
105°C/220°F  79°C/175°F
 138°C/280°F  93°C/200°F
 180°C/356°F (A & F)  105°C/221°F
 180°C/356°F (C)  121°C/250°F
 Type D  38°C/100°F


Detector Wire Type A

  • Jacket material: Vinyl
  • Typical appications: multi-purpose, Commercial and industrial applications
  • Alarm temperatures: 68°C/155°F, 88°C/190°F, 105°C/220°F, 138°C/280°F, 180°C/356°F
  • Umbra item number: 100357xxx (replace "xxx" with alarm temperature in °C)

Detector Wire Type C

  • Jacket material: Polypropylene (flame retardant)
  • Characteristic: good weathering properties and high temperature jacket performance
  • Alarm temperatures: 68°C/155°F, 88°C/190°F, 105°C/220°F, 138°C/280°F, 180°C/356°F
  • Umbra item number: 100045xxx (replace "xxx" with alarm temperature in °C)

Detector Wire Type D

The detector wire of type D uniquely consists of 3 conductors. Because of this the Type D wire combines two alarm temperatures having only one wire installed. It's especially suited for sensitive applications which require a pre-alarm before the activation of the extinguishing system. Applications like this can be realized with the type D employing only one detector wire.

  • Jacket material: Vinyl, durable
  • Typical applications: Applications requiring a pre-alarm
  • Alarm temperature: Pre-alarm 68°C/155°F, Alarm 93°C/200°F
  • Umbra item number: 100047

Detector Wire Type E

The detector wire of Type E is especially suited for cold storage facilities and applications requiring a low alarm temperature.

  • Jacket material: special flame-retardant polymer
  • Typical applications: multi-purpose, excellent low temperature properties
  • Alarm temperature: 57°C/135°F
  • Umbra item number: 100357057

Detector Wire Type F

  • Jacket material: high performance fluorpolymer
  • Characteristic: outstanding resistance against extreme environmental condisiotns and excellent abrasion resistance
  • Alarm temperatures: 68°C/155°F, 88°C/190°F, 105°C/220°F, 138°C/280°F, 180°C/356°F
  • Umbra item number: 100838xxx (replace "xxx" with alarm temperature in °C)

 All necessary information for planning and installation you will find in the product manual. Please let us know in case you need it.

You would like to become a trained installation partner of Umbra FSP for WLM heat detector? You need additional inforamtion about the product, its accessories or planning and installation? Please contact us!



WLM Interfaceeinheit 02b komplettThe WIM (WLM Interface Module) was developed for connecting the WLM detector wire to conventional fire alarm panels.

WIM interpretes the signals of the detector wire and generates the alarm signal for the fir alarm panel. WIM can be mounted close to the protected area and, thus, supports easy accessibility and the possibility to easily check the proper operability.

WIM is (by default) delivered by Umbra FSP as a ready-to-mount unit (see the picture above). The module can be mounted directly to the wall and can be connected with the fire alarm panel and with the WLM detector wire. The WIM is also available in the plain circuit board form.

WIM is available in two series: single line module and dual line module. The dual line module makes it possible to connect two different lines of WLM to just one module. The dual line module is mandatory when using the WLM Type D (pre-alarm detector wire). The dual line module is also available in a ready-to-mount and in a plain finish.

For technical information please contact us.




WireDectBefestigungtranspBased on the number of possible applications WLM detector wire is always to be mounted safely onto different surfaces.

The most important rule is: Do not clamp and compend the detector too much, but keep it safely in position! Tension should be reduced as much as possile.

The accessories shown in the picture below and on our are just samples from the complete range.

Please contact us, in case you have any special requirements or need additional information.

We use cookies on our website that are essential for the operation of the site.

You can decide for yourself whether you want to allow cookies or not. Please note that if you reject them, you may not be able to use all the functionalities of the site.