502.4(B)(3) Nonincendive?
- Thread starter bennie
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...What is the definition and description of "nonincendive"?
- Location
- Illinois
- Occupation
- retired electrician
Re: 502.4(B)(3) Nonincendive?
Bennie,
See the definitions in Article 500. A nonincendive system is step down in protection from an intrinsically safe system. An intrinsically safe system must not be able to provide enough energy to cause an ignition under any conditions, while an nonincendive system must not be able to provide enough energy to cause an ignition under specified test conditions. A nonincendive system is only used in Division 2 locations, while an IS system is used in Division 1 locations.
I do not know where the word "nonincendive" originated.
Don
Bennie,
See the definitions in Article 500. A nonincendive system is step down in protection from an intrinsically safe system. An intrinsically safe system must not be able to provide enough energy to cause an ignition under any conditions, while an nonincendive system must not be able to provide enough energy to cause an ignition under specified test conditions. A nonincendive system is only used in Division 2 locations, while an IS system is used in Division 1 locations.
I do not know where the word "nonincendive" originated.
Don
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: 502.4(B)(3) Nonincendive?
Nonincendive circuit: "A circuit in which any arc or thermal effect produced under intended operating conditions of the equipment is not capable, under the test conditions specified, of igniting the specified flammable gas- or vapor- air mixture."(See UL 1604)
Nonincendive circuit: "A circuit in which any arc or thermal effect produced under intended operating conditions of the equipment is not capable, under the test conditions specified, of igniting the specified flammable gas- or vapor- air mixture."(See UL 1604)
- Location
- Illinois
- Occupation
- retired electrician
Re: 502.4(B)(3) Nonincendive?
Bennie,
Many technical words do not appear in dictionaries. The word is defined in the document that it is used in. There is no additional definition needed as the one in the document where the word appears is the only one that would apply.
Don
Bennie,
Many technical words do not appear in dictionaries. The word is defined in the document that it is used in. There is no additional definition needed as the one in the document where the word appears is the only one that would apply.
Don
Re: 502.4(B)(3) Nonincendive?
While I'm on a roll...Intrinsically is from the latin word intrinsecus, meaning "within".
Intrinsically safe, means " safe within". Safe within would be a sealed switch, such as a mercury or hermatically sealed switch, or a nonincendive system.
A nonincendive system is intrinsically safe. An intrinsically safe system is not always a nonincendive system.
Does this make any sense?
[ July 26, 2003, 06:48 AM: Message edited by: bennie ]
While I'm on a roll...Intrinsically is from the latin word intrinsecus, meaning "within".
Intrinsically safe, means " safe within". Safe within would be a sealed switch, such as a mercury or hermatically sealed switch, or a nonincendive system.
A nonincendive system is intrinsically safe. An intrinsically safe system is not always a nonincendive system.
Does this make any sense?
[ July 26, 2003, 06:48 AM: Message edited by: bennie ]
Re: 502.4(B)(3) Nonincendive?
Someone had to do a lot of research to apply the words "nonincendive" and intrinsically" in the code book, without a clear explanation. Isn't this a bit unusual wording for a code panel to adopt? Who was the author of these sections?
This had to be planned, there is too many words in the section, and some of them may accidentally give a clue to what the heck they are trying to communicate.
Someone had to do a lot of research to apply the words "nonincendive" and intrinsically" in the code book, without a clear explanation. Isn't this a bit unusual wording for a code panel to adopt? Who was the author of these sections?
This had to be planned, there is too many words in the section, and some of them may accidentally give a clue to what the heck they are trying to communicate.
- Location
- Illinois
- Occupation
- retired electrician
Re: 502.4(B)(3) Nonincendive?
Bennie,
These words did not originate in the NEC. They originated in the industry, maybe from equipment manufacturers, and then worked their way into the code requirements.
Don
Bennie,
These words did not originate in the NEC. They originated in the industry, maybe from equipment manufacturers, and then worked their way into the code requirements.
As far as the NEC use of these words your statement is incorrect. All intrinsically safe systems are nonincendive. Nonincendive systems are not intrinsically safe. The nonincendive system can release enough energy to ignite a flammable concentration if the conditions of use are outside of the conditions that the nonincendive system has been tested under. The intrinsically safe system will not provide enough energy to ignite the vapors or dust under any conditions of use or misuse. This is why the nonincendive system can only be used in Division areas while the intrinsically safe system can be used in both Division 1 and 2 areas.
Don
Re: 502.4(B)(3) Nonincendive?
I guess I am missing something. I read...Nonincendive field wiring shall be permitted using any of the wiring methods of unclassified locations. This applies to class 1,2 and 3 locations.
Intrinsically Safe Circuit. A circuit in which any spark or thermal effect is incapable of causing ignition of a mixture of flammable or combustible material in air under prescribed test conditions.
Both systems, properly applied can be used in all 3 locations of hazardous areas.
I guess I am missing something. I read...Nonincendive field wiring shall be permitted using any of the wiring methods of unclassified locations. This applies to class 1,2 and 3 locations.
Intrinsically Safe Circuit. A circuit in which any spark or thermal effect is incapable of causing ignition of a mixture of flammable or combustible material in air under prescribed test conditions.
Both systems, properly applied can be used in all 3 locations of hazardous areas.
- Location
- Illinois
- Occupation
- retired electrician
Re: 502.4(B)(3) Nonincendive?
Bennie,
Yes you could use both system in all three classifications, but not in both division 1 and division 2 using ordinary wiring methods. If you want to use a nonincendive system in a Class 1 Division 1 location you must use explosion proof wiring methods, but an I.S. system can be installed in Class 1 Div 1 with any Chapter 3 wiring method. See 501.4. Nonincendive only appears in 501.4(B) which is the Division 2 section. It does not appear in 501.4(A), the Division 1 section. Intrinsically safe systems do appear in either section but are permitted in Class 1 Division 1 locations using ordinary wiring methods by 504.10(B) and 504.20.
don
Bennie,
Yes you could use both system in all three classifications, but not in both division 1 and division 2 using ordinary wiring methods. If you want to use a nonincendive system in a Class 1 Division 1 location you must use explosion proof wiring methods, but an I.S. system can be installed in Class 1 Div 1 with any Chapter 3 wiring method. See 501.4. Nonincendive only appears in 501.4(B) which is the Division 2 section. It does not appear in 501.4(A), the Division 1 section. Intrinsically safe systems do appear in either section but are permitted in Class 1 Division 1 locations using ordinary wiring methods by 504.10(B) and 504.20.
don
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