1. THUM Adapter Impact on Hazardous Area Classification
Strategies for THUM Adapter Installation

2. Companies Separate Hazardous Areas of a Plant Based on Risk
Class I, Div 2 Area
IEC Zone 2
Hazardous gases are only present under fault conditions
Unclassified Area
Hazardous gases are not present
Class I, Div 1 Area
IEC Zones 1 and 0
Hazardous gases may be present under normal operating conditions
Companies separate hazardous areas of a plant based on risk. Our customers do this and are very familiar with these terms. When talking to the customer, it is important to make sure that you are grounded in the same terms when you discuss approvals for the THUM.
Unclassified areas are areas where hazardous gases are not present. Typically, 25 to 50 percent of their measurement devices are here.
IEC Zone 2 areas are areas where hazardous gases are only present under fault conditions. An example of this is the space around a tank. In most cases, gases will not be present here but if there were a leak in the tank, the gases could be present in this fault condition. This area accounts for 50 to 75 percent of customer measurement devices.
IEC Zone 1 or 0 areas are areas where hazardous gases may be present under normal operating conditions. An example of this is vents that are on tanks. These areas are more restricted and customers try to keep these areas to a minimum. As such, they are typically less than 5 percent of measurement devices.
Bottom Line: Customers want
to limit Div 1 areas due to safety
and environmental concerns

3. What is the Difference Between Intrinsic Safety and Explosionproof Ratings
The energy stored in a device is incapable of causing the ignition of a flammable atmosphere
An IS barrier is needed between the power supply and the device
Depending on specific rating, suitable for Div 1 and 2 as well as Zones 0, 1, and 2
Explosionproof / flameproof
If a hazardous gas is ignited, the explosion is contained within an enclosure
Typically, wiring is in rigid metal conduit or rugged cable which is sealed at the device and at the Div or Zone boundaries
Suitable for Div 1 and 2 as well as Zones 1 and 2. Not generally suitable for Zone 0
Division IEC
Div 1 Zone 0
Zone 1
Div 2 Zone 2
Unclassified Unclassified

4. THUM Can Connect to Any Device With Some Limitations
Class I, Div 2 Area
IEC Zone 2
Install THUM on any device that has a compatible Div. 2 rating.
Unclassified Area
Install THUM on any device
Class 1, Div 1 Area
IEC Zone 1 / 0
Install THUM on any device that has a compatible intrinsic safety rating
or remotely, connect to any device that has an explosion proof rating
The THUM adapter can connect to most devices. There are some limitations on how the THUM adapter can be installed based on the approvals area and rating of the wired device.
In an unclassified area, you can install the THUM on any device. In Class 1 Div 2 or IEC Zone 2 areas, you can install the THUM on any device that has a compatible Div 2 or Zone 2 rating. In Class 1 Div 1 or IEC Zone 1 or 0 areas, you can either install the THUM on any device that has a compatible intrinsic safety rating or you can remotely connect the THUM to any device that has an explosion proof rating. In this case, you would wire the THUM outside of the IEC Zone 1 or 0 area. We will now look at each case a little more in depth.

5. Unclassified Area Mounting Options Special Requirements
Direct or Remote mount
Special Requirements
None
In an unclassified area there are no special requirements for mounting the THUM adapter. It can be both direct or remote mounted.
Power
Supply

6. Div 2 / Zone 2 Area – Typical Method
Hazardous Area
Div 2
Unclassified Area
Power
Supply
Conduit
In a div 2 or Zone 2 the THUM adapter can be either direct or remote mounted. Standard Div 2 / Zone 2 wiring methods must be followed. These typically include conduit or armored cable. If the THUM is remote mounted the wiring between the THUM and the device also needs to use standard Div 2 / Zone 2 practices. You must also ensure that the wired device has the appropriate Div 2 / Zone 2 ratings.
Mounting Options
Direct or Remote mount
Conduit Seal
Special Requirements
Use standard Div 2 / Zone 2 wiring methods
e.g. conduit, armored cable

7. Div 1 / Zone 1 Area – THUM Outside Hazardous Area Method #1
Hazardous Area - Div 2
Unclassified Area
Hazardous Area
Div 1
Unclassified Area
Power
Supply
Conduit Seal
Conduit Seal
Conduit Seal
For Div 1 or Zone 1 Areas where the wired device is using explosion proof or flameproof approvals the THUM adapter needs to be remotely mounted outside of the Div 1 or Zone 1 area. The THUM adapter can be mounted in either a Div 2 / Zone 2 or an unclassified area. The wiring between the THUM adapter and the wired device needs to be standard Div 1 Zone 1 wiring. There also needs to be a conduit seal between the THUM adapter and the wired device.
Mounting Options
Remote mount only
Conduit Seal
Special Requirements
Use standard Div 1 / Zone 1 wiring methods into and out of hazardous area
e.g. conduit with seal, armored cable, etc
Conduit seal locations may vary based on installation and local requirements

8. Div 1 / Zone 1 Area – THUM Outside Hazardous Area Method #2
Hazardous Area - Div 2
Unclassified Area
Hazardous Area
Div 1
Unclassified Area
Power
Supply
For Div 1 or Zone 1 Areas where the wired device is using explosion proof or flameproof approvals the THUM adapter needs to be remotely mounted outside of the Div 1 or Zone 1 area. The THUM adapter can be mounted in either a Div 2 / Zone 2 or an unclassified area. The wiring between the THUM adapter and the wired device needs to be standard Div 1 Zone 1 wiring. There also needs to be a conduit seal between the THUM adapter and the wired device.
Conduit Seal
Conduit Seal
Conduit Seal
Mounting Options
Remote mount only
Conduit Seal
Special Requirements
Use standard Div 1 / Zone 1 wiring methods into and out of hazardous area
e.g. conduit with seal, armored cable, etc
Conduit seal locations may vary based on installation and local requirements

9. Div 2 / Zone 2 Area – Explosionproof/ Flameproof device THUM remains in Hazardous Area Method
Unclassified Area
Power
Supply
Conduit Seal
Conduit Seal
Conduit Seal
Sometimes devices that are only explosionproof or flameproof rate get installed into a Div 2 or Zone 2 area. In these cases the THUM adapter will need to be remote mounted. Since the THUM adapter is Div 2 and Zone 2 rated it does not need to be removed from the Div 2/ Zone 2 area. The wiring that is used will need to meet Div 1 / Zone 1 approvals. A conduit seal will need to be installed between the THUM adapter and wired device.
Mounting Options
Remote mount only
Special Requirements
Use standard Div 1 / Zone 1 wiring methods
e.g. conduit with seal, armored cable, etc
Conduit seal locations may vary based on installation and local requirements

10. THUM installation rules
Above is a chart to help determine the installation requirements for the THUM adapter. Select the column that matches your installation the best and under THUM installation requirements you determine the requirements.
“Transmitter protection” refers to the type of protection that wired device carries. These include explosion proof and Intrinsic Safety.
“Environment” is the Class or Zone that the wired device is located in. These are either Div 1, Div 2, Zone 0, Zone 1, or Zone 2.
“Transmitter Label” refers to the approvals that are called out on the wired devices labels. Some wired devices that are either Explosion proof or Flame proof also carry Div 2 approvals. An easy place to find the approvals that the wired device has is on its labels.
“Transmitter Installation” refers to how the transmitter was installed. In some cases devices that are located in a Div 1 or Zone 2 environment may be installed according to Div 1 or Zone 1 requirements.
“THUM Installation Requirements” are the requirements that you will need to follow to install a THUM adapter onto a wired device in the selected column. If it says Attach directly the THUM adapter can be remotely mounted.

11. Summary THUMs can be attached to just about any device
Device ratings may require additional considerations
Most customers already have similar solutions in place
If you have questions about a specific application, call your support personnel
Note
The information contained in this document is provided for informational purposes only. The installation and operations of electrical equipment must be in accordance with local and national codes and regulations that apply to your facility and satisfy the authorities that have jurisdiction for your location. For installations in the U.S., refer to the National Electrical Code© NFPA 70.
By using direct and remote mounting the THUM adapter can be connected to almost any device. In certain hazardous areas there may need to be additional considerations such as remote mounting and using approved wiring methods. Most of our customers already have similar solutions for many of these cases installed.
Remember that there are many different local and national regulations that can apply to facilities. Customers tend to have resources at their facilities that now the local and national regulations that apply to their facilities, and how their site meets these regulations. The information in this document is for informational purposes only.