Open air spacing

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Dave58er

Dave58er

Senior Member
Location
Dearborn, MI
Here's a challenge from the instructor of a class I'm taking:

Find the maximum spacing for open air wiring methods.
Specifically he's talking about fire alarm cable on J hooks.
I've gotta believe there is a listing with the cable if nothing else. Any reference is acceptable (U.L., NEC, NFPA anything, BOCA, whatever).
He says a spacing max. can't be found.
 
Dave58er said:
Here's a challenge from the instructor of a class I'm taking:
Click to expand...

Dave58er said:
It just can't be that simple. :)
Click to expand...

Why not?
You said it was a "challange".
The instructor probably knows very few will do any research at all...those that do are the ones that have a shot at being "electrical Gods".

Keep in mind most codes are based on a minimum standard...plug that into the question and see what you find ;)
 
Dave,

760.30 Multiconductor NPLFA Cables.(And plfa cables)

(1) Exposed or Fished in Concealed Spaces In raceway or exposed on surface of ceiling and sidewalls or fished in concealed spaces. Cable splices or terminations shall be made in listed fittings, boxes, enclosures, fire alarm devices, or utilization equipment. Where installed exposed, cables shall be adequately supported and installed in such a way that maximum protection against physical damage is afforded by building construction such as baseboards, door frames, ledges, and so forth. Where located within 2.1 m (7 ft) of the floor, cables shall be securely fastened in an approved manner at intervals of not more than 450 mm (18 in.).

Also in nfpa 72, 1-5.5.5 wiring; all wiring shall be install in accordance with the nec
Rick
 
RUWired said:
Dave,

760.30 Multiconductor NPLFA Cables.(And plfa cables)
Click to expand...

How do PFLA cables get in there?

I don't have my 2005 handy but looking at 2002 I don't see how you can include PLFA cables in that requirement.
 
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760.52 Wiring Methods and Materials on Load Side of the PLFA Power Source

(B) PLFA Wiring Methods and Materials Power-limited fire alarm conductors and cables described in 760.82 shall be installed as detailed in 760.52(B)(1), (B)(2), or (B)(3) of this section. Devices shall be installed in accordance with 110.3(B), 300.11(A), and 300.15.

Section 760.52(B) requires mechanical protection at splices and termination points. Because failure of a circuit often occurs at splices or termination points, this requirement offers more protection and strain relief for these cable connections.

(1) Exposed or Fished in Concealed Spaces In raceway or exposed on the surface of ceiling and sidewalls or fished in concealed spaces. Cable splices or terminations shall be made in listed fittings, boxes, enclosures, fire alarm devices, or utilization equipment. Where installed exposed, cables shall be adequately supported and installed in such a way that maximum protection against physical damage is afforded by building construction such as baseboards, door frames, ledges, and so forth. Where located within 2.1 m (7 ft) of the floor, cables shall be securely fastened in an approved manner at intervals of not more than 450 mm (18 in.).

Rick
 
Dave58er said:
Find the maximum spacing for open air wiring methods.
Click to expand...

I do not know but I think if you had one cable in Washington D.C. and the other cable in China you still might be to close together to be at the MAXIMUM spaceing.. If you had one wie here on earth and the other wire on the planet Pluto would you be closer to the maximum spaceing

there are a lot of rules for minimum spaceing but not maximum
 
marinesgt0411 said:
I do not know but I think if you had one cable in Washington D.C. and the other cable in China you still might be to close together to be at the MAXIMUM spaceing.. If you had one wie here on earth and the other wire on the planet Pluto would you be closer to the maximum spaceing

there are a lot of rules for minimum spaceing but not maximum
Click to expand...
Good point. But unfortunatly Pluto is no longer a planet. :confused: according to some scientist:mad:
 
marinesgt0411 said:
there are a lot of rules for minimum spaceing but not maximum
Click to expand...
There must be some word play that I'm missing here. :)

All of the .30's from 300 wiring methods mention spacing not to exceed.
At least 2 of the tables, 344.30(B)(2) & 352.30(B), mention maximum distance & spacing.

Again, maybe I'm just missing a joke. Sometimes you guys need to spell things out for me. I'm really not very brite.:)
 
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