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#89690 - 10/13/04 05:59 AM Intrinsically Safe Circuit
mustangelectric Offline
Member

Registered: 02/08/04
Posts: 496
Loc: Bentonville, AR
hi,
if i seal a conduit as required in a classified area, does this satisfy the requirement for rating a circuit as intrinsically safe?

thanks for any replies.

mustang
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2014 / 2011 NEC & Related Books and Study Guides
#89691 - 10/13/04 11:12 AM Re: Intrinsically Safe Circuit
gfretwell Online   content

Member

Registered: 07/20/04
Posts: 9045
Loc: Estero,Fl,usa
The short answer is no.
Intrinsically safe circuits are those that do not have the energy to cause a spark, it has nothing to do with protection.

See 504 definitions
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Greg Fretwell

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#89692 - 10/13/04 01:07 PM Re: Intrinsically Safe Circuit
mustangelectric Offline
Member

Registered: 02/08/04
Posts: 496
Loc: Bentonville, AR
so if i run lighting to a pump house in an oilfield that is classified class 1 div 1 or class 1 div 2, then those ckts have to be intrinsically safe?

i never saw an intrinsically safe thhn..i have seen shielded cables and explosion proof fittings and enclosures...

the question came up because an inspector is requiring INTRINISCALLY SAFE CKTS at a refuleing station!

some of the control and POS is intrinsically safe but the rest of the building and ckts are normal ckts...these are in unclassified locations...

what could he mean?

here is the exact quote:

"COMPLY NEC 514.11 AND 514.13/SPECIFY ALL CIRCUITS INCL INTERCOMS, LO VOLT CONTROLS, COMPUTERS, INTRINSICALLY SAFE, ETC)."

these articles have nothing to do with intrinsic ckts...that i could tell..

thanks for the replies

mustang

[This message has been edited by mustangelectric (edited 10-13-2004).]

[This message has been edited by mustangelectric (edited 10-13-2004).]
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#89693 - 10/13/04 02:35 PM Re: Intrinsically Safe Circuit
trekkie76 Offline
Member

Registered: 06/19/04
Posts: 219
Loc: baileyville, maine, usa
did the inspector just want disconnects that comply with those sections? I interpret the end of that quote as some kind of labeling/indentification requirement.

[This message has been edited by trekkie76 (edited 10-13-2004).]

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#89694 - 10/14/04 02:01 PM Re: Intrinsically Safe Circuit
mustangelectric Offline
Member

Registered: 02/08/04
Posts: 496
Loc: Bentonville, AR
hi,
i am working from code comments...never spoke to him...maybe it will take a phone call or e-mail to figure it out..

i am still trying to figure it out!

thanks for the replies..

mustang
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#89695 - 10/14/04 04:09 PM Re: Intrinsically Safe Circuit
resqcapt19 Offline
Member

Registered: 11/10/00
Posts: 2209
Loc: IL
 Quote:
so if i run lighting to a pump house in an oilfield that is classified class 1 div 1 or class 1 div 2, then those ckts have to be intrinsically safe?

I don't think that it is even possible to have an intrinsically safe lighting circuit. For an instrinsically safe circuit there must be no possible way to cause a spark that has enough energy to ignite the gasses, even if you short the conductors. Lighting would have to be of the type approved for the area classification and the raceways and seals will have to comply with Article 501.
Don
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#89696 - 10/14/04 04:11 PM Re: Intrinsically Safe Circuit
resqcapt19 Offline
Member

Registered: 11/10/00
Posts: 2209
Loc: IL
 Quote:
"COMPLY NEC 514.11 AND 514.13/SPECIFY ALL CIRCUITS INCL INTERCOMS, LO VOLT CONTROLS, COMPUTERS, INTRINSICALLY SAFE, ETC)."

Is this installation a gas station? That is the application of Article 514. It does not apply to other classified areas.
The code sections cited require that there be a means of disconnect for all circuits of any type that serve a fuel dispensing unit, and do not apply to any other classified areas.
Don



[This message has been edited by resqcapt19 (edited 10-14-2004).]
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#89697 - 10/14/04 06:25 PM Re: Intrinsically Safe Circuit
Norstarr Offline
Member

Registered: 09/25/04
Posts: 89
Loc: Wi
Mustang,
I have found that you have to really educate yourself regarding hazardous locations. A lot of inspectors are not completely informed of the requirements and therefore make guesses. If you are installing a light fixture it can not be made intrinsically safe. It must be a fixture rated and listed for the hazardous location with the proper raceway and seals. Usually only control items can be made intrinsically safe, such as float switches etc, using the proper components.
I had an inspector walk in on a job I did and condemned the job as soon as he saw thinwall. Kept repeating "All wiring in a hazardous location must be in rigid". He could not understand "intrinsically safe". Took a lot of my time meeting with him and his boss to get it approved. Because I took the time to read and read until I understood hazardous location wiring I was able to stand there, proud of the job, knowing I would not have to change anything. I'm sure if you ask the inspector face to face what his interpretation is you will both learn and the job will be safe.
Ron

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