Fixed Activation FAQ's

The low smoke zero halogen outer coat maintains flexibility at low temperatures and enables the detection cable to operate continuously in temperatures as low as -60⁰C. The maximum ambient operating temperature is determined by the alarm temperature and can be found in the installation manual.

The low smoke zero halogen outer coat has good resistance against ammonia, copper nitrate, hydrofluoric acid and acetic acid.

Please contact us if you have a question on the chemical compatibility of this material.

Thermocable’s ProReact Plus Digital LHD cable is both UL and ULC approved. This approval covers both the low smoke zero halogen outer coat and the optional stainless steel outer braid.

Low smoke zero halogen cables are being increasingly specified and used in environments where smoke and harmful emissions released in the event of a fire could endanger human life. ProReact Plus Digital LHD cable is a low smoke zero halogen, UV stable and hydrocarbon resistant alternative to traditional digital linear heat detection cable.

The low smoke zero halogen outer coat has good resistance against ammonia, copper nitrate, hydrofluoric acid and acetic acid.

Please contact us if you have a question on the chemical compatibility of this material.

This detection cable is available in 100 metre, 200 metre or 500 metre reel lengths as standard. Non-standard lengths can be supplied but will incur a small surcharge. Please note that the maximum available reel length is 500 metres per spool.

The ProReact EN Digital LHD cable (various alarm temperatures available), the ProReact Digital Sensor Control Unit (DSCU) and the ProReact Digital End of Line Unit (EOLU) are all listed as components on the system approval certificate.

Thermocable had to introduce hardware and software modifications to its existing ProReact Digital LHD range in order to meet the requirement of EN54-28. As a result, these two systems are materially different and are not cross-compatible. I.e., you cannot use ProReact Digital LHD cable with a ProReact Digital Sensor Control Unit (DSCU).

An unintended consequence of making these changes is the reduction in maximum zone length per zone of detection cable. This is 1,000 metres per zone for the ProReact EN Digital LHD system. However, please note that two zones of detection cable can be connected to a single ProReact Digital Sensor Control Unit.

Yes, to our knowledge we were the first manufacturer to have a full system (consisting of detection cable, an interface unit and end of line unit) certified according to EN54-28.

They provide a technical basis to assess the performance of construction products and they enable manufacturers to draw up declarations of performance and affix CE and UKCA marking. Products that are resistant to fire or react to fire fall under the definition of construction products in the European Union.

This European Standard applies to non-resettable line-type heat detectors consisting of a sensing element using an electrical sensor cable which can be connected to a sensor control unit or either directly or through an interface module to a control and indicating equipment intended for use in fire detection and fire alarm systems installed in and around buildings and civil engineering works.

Thermocable supports the Fire Industry Association’s guidance on the life expectancy of fire detection and alarm systems providing that its products have been installed as per the installation manual, are not exposed to temperatures outside of their ambient operating range and are tested regularly. The FIA states it is considered that heat detectors would not be expected to deteriorate even over extended periods well in excess of 10 years.

ProReact VHT Digital Linear Heat Detection cable can continuously operate in temperatures up to 170⁰C without deterring its performance.

The outer silicone jacket on the detection cable has good or better resistance to the following chemicals: ammonia, copper nitrate, fuel, gasoline, kerosene, diesel and acetic acid.

There is no minimum zone length for this linear heat detection cable.

ProReact VHT Digital Linear Heat Detection cable is a specialist detector designed for environments in which standard linear heat detection or other types of detectors would be unsuitable. Such applications include vehicle engine bays, commercial kitchens and manufacturing or industrial plants.

The ProReact Digital Interface Units are IP65 rated and measured as follows:
Height: 180mm x Width: 120mm x Depth: 60.5mm (H7.1in x W4.72in x D2.38in)

Yes. In certain applications it may be desirable or necessary to use non-sensing leader cable between a ProReact Digital interface unit and Digital LHD cable. For example, if the interface unit is located some distance away from the area protected by the Digital LHD cable. This may be required if the expected ambient temperature range, or other environmental conditions, where the Digital LHD cable is to be used is greater than the maximum ambient temperature range for the interface unit.

The maximum length of leader cable that can be used per zone is dependent upon the leader cable diameter. Please contact us if you require any further information.

Independent – This is when the interface unit is used as a two zone system. When a fault or overheat condition occurs on a Digital LHD zone, the corresponding fault or alarm output respectively is triggered. The two zones operate independently and both sets of outputs should be connected to a fire alarm control panel. If the zone is not required leave the 3.6kohm resistor in the zone input terminals as supplied. In this mode, the two zones can either contain identical rated temperature Digital LHD cables or two different rated temperature Digital LHD cables.

Interlock – this mode is for applications which require a fail-safe guarantee that an alarm is only triggered when an overheat condition has been detected. This mode may also be known as coincidence detection. In this case, the same rated temperature Digital LHD cable should be attached to both zones of the interface unit. The alarm output is only activated when both Digital LHD cables trigger an alarm due to an overheat condition. If one Digital LHD cable zone input registers an alarm but the second does not, the alarm output will not be activated. This is to prevent an alarm if a mechanical or other issue has triggered one Digital LHD cable and not an overheat condition.

Please see below the information for the fire and fault outputs:
Fault condition
2x Form C volt-free relay contacts (resistive, common)
Max V – 30Vac or 42.4Vdc
Max Current – 2A
Max Switching Power – 60W, 62.5VA

Fire condition
2x Optoisolated phototransistor output (resistive, common)
Max V – 35Vdc
Max Current – 80mA
Max Power Dissipation – 150mW

The recommended ambient operating temperature range is between -20°C and +50°C (-4°F – +122°F).

Thermocable’s ProReact Digital Interface Monitor Module and the ProReact Digital Sensor Control Unit require a 24V power supply.

Operating Voltage Range – 0-30Vac, 0-42Vdc
Resistance – Approx. 100Ω/km (30.4Ω/kft) per leg
Velocity of Propagation – Approx. 55%
Capacitance – 88 – 150pF/m
Inductance – 540 – 1050nH/m

Yes, intrinsically safe barriers must be installed between a hazardous area and safe area. More information can be found in our hazardous area installation guides.

Please find a summary of the compatibility by material below. More information can be supplied on request.
PVC is resistant to ammonia, copper nitrate, fuel oil and diesel fuel
Nylon is resistant to butane, fuel oils, gasoline, methyl ethyl ketone, diesel, ethyl alcohol and ethanol
Polypropylene is resistant to ammonia, copper nitrate, hydrofluoric acid, diesel and acetic acid
Stainless Steel is resistant to ammonia nitrate, , butane, copper nitrate, fuel, gasoline, methyl ethyl ketone, diesel, ethyl alcohol and ethanol

All Thermocable’s ProReact Digital Linear Heat Detection Cable has a minimum ambient operating temperature of -40⁰C (-40⁰F) and can operate between 0-100% relative humidity.
Please find the recommended maximum ambient operating temperatures below:

Two zones of ProReact Digital Linear Heat Detection cable can be connected to a ProReact Digital Interface Monitor Module.

There are no restrictions in place for the minimum amount of detection cable installed per zone or system.

Each zone of ProReact Digital Linear Heat Detection cable can contain up to 3,000 metres. Two zones of detection cable can be connected into a ProReact Digital Interface Monitor Module allowing the maximum length of detection cable per system to be up to 6,000 metres.

The maximum ambient operating temperature of digital linear heat detection cable must be adhered to during transport and storage. Thermocable make this information clear on its packaging for the avoidance of doubt. Detailed information on the ambient operating temperature of linear heat detection products should be listed within the installation manual.

Functional testing of digital linear heat detection by heating a section of cable up until an alarm is initiated is an effective method but can be costly as the section of cable must be replaced following the test.

Alternatively, it is possible to undertake a test using Thermocable’s ProReact Digital EOL unit with Test Facility (SKU: A1385). This unit allowed a functional test to be carried out on the zone of digital LHD cable to verify normal, trouble and alarm functions of the system by simulating a break in the cable or a overheat condition.

Please get in touch with us if you require further clarification on testing a digital linear heat detection system.

Yes, each zone (or “run”) of digital linear heat detection cable should be connected to an end of line unit.

Yes, this is possible. Please note that two lengths of digital linear heat detection cable should be connected using a junction box.

Thermocable typically supplies its ProReact Digital Linear Heat Detection cable on its standard reel lengths of 100m, 200, 500m or 1,000m where available. Alternatively, non-standard lengths can be supplied at an additional cost on request.

Thermocable has referred to the colour coding for heat detectors within NFPA 72 when designing its products. The colour of its ProReact Digital Linear Heat Detection cable is as follows:

Alarm temperature of 79⁰C and below – Red
Alarm temperature between 80⁰C and 121⁰C – White
Alarm temperature between 122⁰C and 162⁰C – Blue
Alarm temperature between 163⁰C and 204⁰C – Red
Alarm temperature between 205⁰C and 259⁰C – Green

An optional black nylon outer coat and / or a stainless steel outer braid can be added to the majority of our detection cables.

Digital linear heat detection cable is often referred to as non-resettable as a physical change takes place in the detection cable once the alarm temperature is reached and the cable must be replaced following a fire or overheat condition. It is constructed of two metal core wires that come into contact at a certain temperature and, in doing so, create a short circuit. This triggers a resulting alarm on the interface unit or fire control panel.