FIber Optic Cables in Class I Div 1 area

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nhee2

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I am confused by 501.10(A)(1)(e) which states that certain types optical fiber cables can be installed in raceways in accordance with 501.10(A). Does this mean that for FO cables installed in conduit through a Div 1 area, all fittings, pull boxes, etc. would be required to be approved for Division 1 (501.10(A)(3))? I would have guessed that boxes could be general purpose, and that the only consideration for the cable installation would in hazardous area would be installation of seals at the location boundaries.

Does FO installation in Class I Div 1 areas require explosion-proof, approved boxes?
 
nhee2 said:
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Does FO installation in Class I Div 1 areas require explosion-proof, approved boxes?
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Yes, generally.

Unless the FO system is also demonstrably an intrinsically safe system, if the cables are installed in raceways in a Class I, Division 1 location, the entire raceway system must be suitable for Class I, Division 1. This is unlike installations under Article 504 where seals aren't even required to be explosionproof.

FWIW, Section 501.10(A)(1)(e) lists all FO Type cables recognized in Article 770. Of course it is assumed the installation is also consistent with Article 770.
 
rbalex said:
Yes, generally.

Unless the FO system is also demonstrably an intrinsically safe system, if the cables are installed in raceways in a Class I, Division 1 location, the entire raceway system must be suitable for Class I, Division 1. This is unlike installations under Article 504 where seals aren't even required to be explosionproof.

FWIW, Section 501.10(A)(1)(e) lists all FO Type cables recognized in Article 770. Of course it is assumed the installation is also consistent with Article 770.
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Thanks.

I had (incorrectly) assumed that FO installations would inherently be IS.
 
nhee2 said:
Thanks.

I had (incorrectly) assumed that FO installations would inherently be IS.
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Well, if they were inherently IS you wouldn't need to deal with Section 501.10 at all, just Art 504. Many are, of course but you do need to document it.
 
rbalex said:
Well, if they were inherently IS you wouldn't need to deal with Section 501.10 at all, just Art 504. Many are, of course but you do need to document it.
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So even if you have fiber that does not have a conductive element, you still need documentation to say that it is IS? I am assuming that only the fiber is in the classified area.
 
rbalex said:
Many are, of course but you do need to document it.
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Do you have any examples of listed IS fiber devices?

In this instance I'm talking about a network fiber optic cable (Ethernet communications). Assuming my network hardware/modules are installed in protected or non-hazardous areas, and that only the fiber optic cable passes through the Class I Div 1 location. Are there listed IS network switches? Or is some sort of IS barrier required, similar to other IS installations? I just did a quick scan through PF, MTL, RStahl sites and did not see anything specific to fiber, and did not see any IS listing info on some of the industrial fiber converters and switches I am familiar with.

Maybe I am looking in the wrong spot.
 
don_resqcapt19 said:
So even if you have fiber that does not have a conductive element, you still need documentation to say that it is IS? I am assuming that only the fiber is in the classified area.
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nhee2 said:
Do you have any examples of listed IS fiber devices?

In this instance I'm talking about a network fiber optic cable (Ethernet communications). Assuming my network hardware/modules are installed in protected or non-hazardous areas, and that only the fiber optic cable passes through the Class I Div 1 location. Are there listed IS network switches? Or is some sort of IS barrier required, similar to other IS installations? I just did a quick scan through PF, MTL, RStahl sites and did not see anything specific to fiber, and did not see any IS listing info on some of the industrial fiber converters and switches I am familiar with.

Maybe I am looking in the wrong spot.
Click to expand...
The thing to remember is if it isn't installed per Article 504, with all its attending bells and whistles like a control drawing, it isn't an intrinsically safe system.
 
"the associate fire hazard" and "the associated explosion hazard". So the assumption is that an optical fiber can generate enough energy to cause a fire or explosion?

Interesting that it (and 2014) only reference Article 501, 502 and 503 for installation but not 504.
 
Actually, the assumption is that fiber optics aren't automatically intrinsically safe.

Notice intrinsic safety is not defined in Section 500.2 nor is it mentioned in Articles 501, 502 or 503. It is recognized as a protection technique in Section 500.7(E) when it is installed per Article 504.
 
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