Hazardous Area Products - Frequently Asked Questions

Q. Are CTC hazardous-rated sensors approved for use in portable applications? 

A. No. All CTC hazardous-rated sensors are designed exclusively for permanent stud mounting. Portable or handheld use is not approved and would violate the terms of the certification. For every hazardous-rated sensor, an installation control drawing is posted on its product webpage. This drawing outlines the approved mounting method and must be followed to maintain compliance with the certification. 

Q: Can I use a magnet mounting base to install a CTC hazardous-rated sensor, even if I don’t plan to remove it? 

A: No. CTC hazardous-rated sensors are certified for permanent stud mounting only. Magnet mounts are not approved for permanent installations. Always follow the approved installation method detailed in the sensor’s control drawing to ensure safety and maintain certification. 

Q. How do I know what cabling and accessories are approved for use with CTC hazardous-rated sensors? 

A. CTC has developed comprehensive tools and documentation to simplify the selection of approved compatible hardware: 

• Each hazardous-area approved sensor datasheet clearly lists approved cables. If an intrinsically safe barrier is required, that will also be noted on the datasheet. Our System Wizard will also advise on the maximum allowable cable length, which is clearly listed in the ordering details for integral cable versions and is also noted on the system wizard when configuring compatible cables.
  
  
• When you add a sensor to your cart on CTC's website, you'll be prompted with a question asking if you want to build a complete system. If you choose to do so, our System Wizard will walk you through selecting on ly approved and compatible accessories, including cables, enclosures, and barriers, to ensure that your system meets hazardous area requirements.

Q. Can I mix CTC sensors with third-party cables or connectors in hazardous areas? 

A. No. Using non-approved cables or accessories invalidates the certification of the entire system. CTC hazardous-rated sensors must only be used with approved accessories listed on the datasheet or configured through the System Wizard. This ensures certification compliance, safe operation, and system reliability.

Q: Do I need armored cable for hazardous area applications? 

A. No, you do not specifically need armored cable for hazardous area applications. You can use any of the approved cables listed for the sensor on its datasheet — most of which are available in both armored and standard cable versions.

Armored cable is recommended only when there is a concern about physical damage to the cable, such as exposure to debris, abrasion, or other worksite hazards. Otherwise, standard approved cable is sufficient to maintain hazardous location compliance.

Always refer to the sensor's datasheet or use CTC's System Wizard to select approved cable types appropriate for your installation environment.

Q: Does CTC offer hazardous-rated junction boxes?

A. No, CTC does not manufacture hazardous-rated junction boxes. However, CTC standard junction boxes can still be used, as long as they are located outside of the hazardous zone.

To remain compliant:

• An approved cabling method must be used between the hazardous area sensor and the junction box.
  
  
• The System Wizard will guide you in selecting the right cable, determine if an intrinsically safe barrier is required, and show you the maximum allowable cable length.
  
  
• All terminations into junction boxes must be in the safe (non-hazardous) zone.

Q: How do I know how many barriers I need per sensor for multi-axis hazardous-rated sensors?

A. CTC intrinsically safe sensors require the use of our IS111-1B barrier, which is a dual channel barrier.

• For dual output sensors, typically one dual channel barrier is sufficient.
  
  
• For triaxial sensors, you will generally need two dual channel barriers - one to cover two outputs, and a second to cover the third output.

The exact number of required barriers for each sensor is always clearly listed on the sensor's datasheet and control drawing, along with wiring diagrams that ensure safe and compliant installation.

Q: Why do I need an intrinsically safe (IS) barrier for some sensors and not others?

A. Intrinsically safe (IS) sensors are designed for use in Zone 0/1 or Division 1 environments - areas where explosive atmospheres are continuously or frequently present. In these high-risk zones, IS barriers are required to limit the electrical energy entering the hazardous area. This prevents sparks or heat that could ignite flammable gases, vapors, or dust.

On the other hand, Zone 2 or Division 2 areas are considered less hazardous. Explosive atmospheres are not normally present, and if they are, it's only for short periods. Sensors rated for these environments are often non-incendive, meaning they are safe to use without barriers, provided they're installed per the control drawing, with approved cabling, and to local code requirements.

To summarize:

• IS sensors (Zone 0/1, Division 1) - require barriers to control energy levels.
  
  
• Zone 2, Division 2 sensors - do not require barriers, but must still be installed correctly with approved cabling.

Always refer to the sensor's control drawing and applicable standards to ensure safe and compliant installation.

Q: Why do I need an intrinsically safe (IS) barrier for some sensors and not others?

A. Intrinsically safe (IS) sensors are designed for use in Zone 0/1 or Division 1 environments - areas where explosive atmospheres are continuously or frequently present. In these high-risk zones, IS barriers are required to limit the electrical energy entering the hazardous area. This prevents sparks or heat that could ignite flammable gases, vapors, or dust.

On the other hand, Zone 2 or Division 2 areas are considered less hazardous. Explosive atmospheres are not normally present, and if they are, it's only for short periods. Sensors rated for these environments are often non-incendive, meaning they are safe to use without barriers, provided they're installed per the control drawing, with approved cabling, and to local code requirements.

To summarize:

• IS sensors (Zone 0/1, Division 1) - require barriers to control energy levels.
  
  
• Zone 2, Division 2 sensors - do not require barriers, but must still be installed correctly with approved cabling.

Always refer to the sensor's control drawing and applicable standards to ensure safe and compliant installation.

Q: Where can I find certification documents for a specific sensor?

A. Certification documents, including the formal certificate, installation control drawing, and manual, are available for every hazardous-rated sensors that CTC offers. These can typically be found on the sensor's product page, under the buttons on the right side of the page. There will be specific buttons for installation drawing, product manual, and ratings and approvals.

Q: Where can I find the approved markings for a specific sensor?

A. The approved hazardous area markings for a specific CTC sensor are listed directly on the product datasheet in the top right corner. These markings indicate the certification type (e.g. ATEX, IECEx, or CSA), zone or division classification, protection method, and temperature rating. 

In addition to the datasheet, the same markings are referenced in the official certification documents, which are available on the Products section of the CTC website, under the Certifications link. Always ensure that the markings on your installed sensor matches the requirements of your installation environment.

Q: My sensor has multiple approved certifications - how do I know which one applies to my application?

A. If a sensor has been certified by multiple agencies (e.g. ATEX, IECEx, CSA), you should select the certification that aligns with the specific hazardous area classification and regulatory authority in your region or facility.

For example:

• ATEX is typically required in the European Union
  
  
• IECEx is used internationally and often accepted in global projects
  
  
• CSA (North American certifications) are used for installations in the United States and Canada, covering Class/Division or Class/Zone classifications.

Each certificate outlines the specific area classification (e.g. Zone 1, Division 1), protection method (e.g. Ex ia, Ex nA), and temperature rating. It is only necessary to reference the standards of the specific certificate that would cover your application.

Q: What are the differences between Classes, Divisions, and Zones in hazardous area classifications?

A. Hazardous area classifications define the types of explosive atmospheres that may be present in a work environment and how often those conditions occur. Two main systems are used globally: the Class/Division System (primarily used in North America), and the Zone System (used internationally, including Europe and other global regions). 

Here's a breakdown:

• Class/Division System (used in U.S. and Canada)
  
  
  • Classes define the type of hazard:
    • Class I - Flammable gases or vapors
    • Class II - Combustible dusts
    • Class III - Ignitable fibers or flyings
      
      
  • Divisions define how often the hazard is present:
    • Division 1 - The hazardous material is present during normal operations
    • Division 2 - The hazardous material is present only under abnormal conditions (e.g. leaks)
      
      

• Zone System (used globally, based on IEC and ATEX standards)
  
  
  • Zones define the frequency and duration of the hazardous atmosphere:
    • Zone 0 - Explosive atmosphere is continuously present or present for long periods
    • Zone 1 - Explosive atmosphere is likely to occur in normal operation
    • Zone 2 - Explosive atmosphere is unlikely to occur in normal operation, and if it occurs, it's for a short time
      
      
  • Dust Zones follow a similar pattern:
    • Zone 20 - Continuous presence of combustible dust
    • Zone 21 - Likely presence during normal operations
    • Zone 22 - Unlikely or short-term presence

Q: Does CTC offer hazardous rated sensors with mining protections?

A. CTC does offer mining-rated protection under international standards, including:

• ATEX: Ex ia I Ma
  
  
• IECEx: Ex ia I Ma
  
  
• ANZEx: Ex ia I Ma 

These certifications mean that select CTC sensors are approved for use in underground mining environments (Group I), with the highest level of intrinsic safety protection ("ia") and the most robust Equipment Protection Level ("Ma"), suitable for continuous presence in hazardous mining atmospheres such as methane gas or coal dust.

CTC does not currently hold mining approvals for North America, such as MSHA (Mine Safety and Health Administration) certifications.

Q: What are temperature codes and why do they matter for hazardous area sensors?

A. Temperature codes (T-codes) indicate the maximum surface temperature a device can reach under fault or normal conditions. This is critical because different flammable gases, dusts, and vapors ignite at different temperatures. The T-code ensures the sensor will never get hot enough to ignite the hazardous atmosphere it's in.

T-Code Maximum Surface Temperature:

• T1: 450 °C
  
  
• T2: 300 °C
  
  
• T3: 200 °C
  
  
• T4: 135 °C
  
  
• T5: 100 °C
  
  
• T6: 85 °C

The lower the T-code number, the higher the allowable temperature. For example, T4 is safer than T3 in terms of ignition potential. For a T4 rating, it means equipment will never exceed 135 °C, making it suitable for environments with lower ignition temperatures.

Let's say a flammable gas in your area has an autoignition temperature of 180 C:

• T3 Rated Equipment (200 °C): would exceed that, posing an ignition risk
  
  
• T4 Rated Equipment (135 °C): stays safely below that threshold, making it the safer choice