Non-Incendive Devices

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Mike3333

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I am working in a Class 1 Div 2 area and have looked at Non-Incendive devices for this area, and have a few questions regarding the installation. The device in question is a temperature transmitter which is loop powered by 9.5 Vdc to 28 Vdc.

The transmitter Entity Parameters are: Vmax=28Vdc, Imax=100mA, C=0.037uF and L=0mH. I am not sure if the transmitter is powered, or if the device is truely just loop powered; however, I assume the following: If the transmitter has sperate power wires (4-Wires), if I fuse this circuit at or less than 100mA, I cover the Imax. Also, my power supply is rated at 24 Vdc, which I assume covers the Vmax. If my device is a true loop powered device (2-Wires) the analog module I am using is rated at 60mA @ 24Vdc, which I assume covers both the Vmax, and Imax of the entity parameters. If these answers are true, I still have the following questions:

Questions:
1. Can my device be powered by a power supply (24 Vdc), which powers all other non rated devices in my control system?
2. Can the wires for this device share the way wire way inside my control cabinet (MCP) and a wire duct above my MCP, prior to entering a single conduit to the rated device?
3. Can I simply recreate the manufacture's drawing into my control system drawing set, or does this OEM drawing get affixed to my drawing set?
4. If I can recreate the OEM drawing, what information has to be included?

Thanks for taking a look at my questions!

MIke
 
Nonincendive Circuits are generally covered in Section 501. 10(B)(3). It isn?t as comprehensive as Article 504 for intrinsically safe systems and there are several cross-references to other Sections and Articles which makes it a bit hard to follow.

Personally, I?m not qualified to say the device you have described actually is nonincendive; however, the OEM documents you have referred to should have a control drawing (a defined term in 500.2) that will answer most of your questions. The control drawing will self identify under ANSI/ISA 12.12.01 requirements. (It will need to meet the ANSI/ISA 12.12.01 requirements in order to be listed)

The control drawing does not necessarily need to be duplicated on your own drawings but it should be clearly referenced.

Circuit isolation requirements are described in Section 501. 10(B)(3). They are minimal but they do exist.
 
Thanks for your reply. I'm still confused with regard to my above questions, and I'm just looking for a little clairification. I believe this code was indtroduced to make engineering easier and less costly, but there seems to be a lack of application samples to verify my thinking. I would prefer to not over design (C1D1), or use barriers if there is a safe way to move in that direction. Again, thanks for your reply! Mike
 
With respect to the specific questions in the OP

1. As I said, I?m not qualified but the control drawing that you are required to secure from the manufacturer should answer your question.
2.Assuming this definitely is a nonincendive device the wires can share raceways/wireways subject to any restrictions from the control drawing and the three additional restrictions that are listed at the bottom of 501.10(B)(3).
3. I did answer that directly in my original reply.
4. If you DO recreate the control drawing, I would recommend recreating it in its entirety and note that it WAS a recreation.
 
Thanks! It helps if I actually look at the "Right" code sections you suggested. So now I assume if the device is FM approved as a non-incendive device, and I wire it as stated in the OEM electrical documention, I can run the field wires as stated in 501.10(B)(3) and be compliant....

Thanks for the insight!
 
Mike3333 said:
I am working in a Class 1 Div 2 area and have looked at Non-Incendive devices for this area, and have a few questions regarding the installation. The device in question is a temperature transmitter which is loop powered by 9.5 Vdc to 28 Vdc.

The transmitter Entity Parameters are: Vmax=28Vdc, Imax=100mA, C=0.037uF and L=0mH. I am not sure if the transmitter is powered, or if the device is truely just loop powered; however, I assume the following: If the transmitter has sperate power wires (4-Wires), if I fuse this circuit at or less than 100mA, I cover the Imax. Also, my power supply is rated at 24 Vdc, which I assume covers the Vmax. If my device is a true loop powered device (2-Wires) the analog module I am using is rated at 60mA @ 24Vdc, which I assume covers both the Vmax, and Imax of the entity parameters. If these answers are true, I still have the following questions:

Questions:
1. Can my device be powered by a power supply (24 Vdc), which powers all other non rated devices in my control system?
2. Can the wires for this device share the way wire way inside my control cabinet (MCP) and a wire duct above my MCP, prior to entering a single conduit to the rated device?
3. Can I simply recreate the manufacture's drawing into my control system drawing set, or does this OEM drawing get affixed to my drawing set?
4. If I can recreate the OEM drawing, what information has to be included?

Thanks for taking a look at my questions!

MIke
Click to expand...
Can somebody clarify how Non incendive device differs intrinzic safe device?
where you should use former instead of later?
Thanks in advance.
 
What is gained by using a nonincendive circuit for this application? I would expect that a standard transmitter would be fine in a Class I, Division 2 area.
501.105(B)(2) ... Exception: General-purpose-type enclosures shall be permitted if such equipment is without make-and-break or sliding contacts [other than as provided in 501.105(B)(1)] and if the maximum operating temperature of any exposed surface will not exceed 80 percent of the ignition temperature in degrees Celsius of the gas or vapor involved or has been tested and found incapable of igniting the gas or vapor. This exception shall not apply to thermionic tubes.
Click to expand...
I would assume that the normal operating temperature of the transmitter would be much less than 80% of the ignition temperature of the flammable product.
Don
 
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