Fiber Optic in Handhole with Power Conductors

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Bob Carroll

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I'm doing a site lighting job in Chicago,Illinois and the customer would like us to add a raceway for future security( cameras most likely fiber optic due to length). Is it acceptable to run this raceway through the same hand holes we are installing for power? These are 4'x4'x4' manholes
 
I don't believe that would be compliant unless the fiber optic was rated the same voltage as the voltage on the power conductors. Wait and see what others say.

BTW, I changed the title of the thread...Your name was not a good title--LOL
 
I don't think there is an issue with installing fiber in the same handhole as lighting conductors so long as terminations are not made in the handhole and they are operating at 600V or less. You could put a listed or permanent divider per exception #5 in the handhole if that isn't the case.

Additional reading, EC&M Article by Mike Holt

To me, it is unclear if the second set of underlined text includes a hand hole.

See 2011 NEC, 770.133 (A)
Nonconductive optical fiber cables shall be permitted to
occupy the same cable tray or raceway with conductors for
electric light, power, Class 1, non–power-limited fire alarm,
Type ITC, or medium-power network-powered broadband
communications circuits, operating at 600 volts or less.​

Nonconductive optical fiber cables shall not be permitted​
to occupy the same cabinet, outlet box, panel, or similar​
enclosure housing the electrical terminations of an electric​
light, power, Class 1, non–power-limited fire alarm, or​
medium-power network-powered broadband communications​
circuit.​


​
Exception No. 5: Where all of the conductors of electric​
light, power, Class 1, nonpower-limited fire alarm, and​
medium-power network-powered broadband communications​
circuits are separated from all of the optical fiber​
cables by a permanent barrier or listed divider.​
 
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Dennis Alwon said:
I don't believe that would be compliant unless the fiber optic was rated the same voltage as the voltage on the power conductors. Wait and see what others say.

BTW, I changed the title of the thread...Your name was not a good title--LOL
Click to expand...

hm. as fiber optic isn't a conductor....... does it need a voltage
rating, and does it actually count *as* a conductor?
 
drktmplr12 said:
See 2011 NEC, 770.133 (A)
Nonconductive optical fiber cables shall be permitted to
occupy the same cable tray or raceway with conductors for
electric light, power, Class 1, non–power-limited fire alarm,
Type ITC, or medium-power network-powered broadband
communications circuits, operating at 600 volts or less.​

Nonconductive optical fiber cables shall not be permitted​
to occupy the same cabinet, outlet box, panel, or similar​
enclosure housing the electrical terminations of an electric​
light, power, Class 1, non–power-limited fire alarm, or​
medium-power network-powered broadband communications​
circuit.​
Exception No. 5: Where all of the conductors of electric​
light, power, Class 1, nonpower-limited fire alarm, and​
medium-power network-powered broadband communications​
circuits are separated from all of the optical fiber​
cables by a permanent barrier or listed divider.​
Click to expand...

This is giving me a headache. Why can they be in the same conduit or cable tray where they will almost certainly be in physical contact, but they can't be in the same box without a divider, even if they are separated by 2" (which is one allowance for low voltage conductors to be in the same handhole with power conductors)?

They can't even be in the same box if they are 2 feet apart!! That just doesn't make any sense, or am I reading that completely wrong?
 
steve66 said:
This is giving me a headache. Why can they be in the same conduit or cable tray where they will almost certainly be in physical contact, but they can't be in the same box without a divider, even if they are separated by 2" (which is one allowance for low voltage conductors to be in the same handhole with power conductors)?

They can't even be in the same box if they are 2 feet apart!! That just doesn't make any sense, or am I reading that completely wrong?
Click to expand...

The other distinction is that the second paragraph only applies when there are terminations of wires within the enclosure (which cannot happen in first paragraph raceway).
I suppose they might be concerned about the fiber getting in the way or being damaged while work other than pulling was being done inside the enclosure.
 
I'm speculating that the reasoning is that terminations are a point where a fire may start. The code might be concerned that the fiber optic cable will spread the fire to an adjacent space, hence the 'listed' barrier.

Although there are plenum and riser rated fiberoptic cables that are flame retardant, most general purpose fiber optic cables are constructed from materials that can incinerate and spread fires. Not to mention release loads of really nasty black smoke.
 
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Note that some fiber cables have metal armor under the plastic - sort of like jacketed MC. This metal sheath will be typically grounded in the communication center termination.
 
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