[TowerTalk] 220v trench proximity to 7/8” feedline trench?

[jimlux]

On 8/7/20 3:29 PM, john nistico wrote:
> You should never run line voltage in the same conduit or within 3 feet of lines unless the insulation voltage ratings are rated for the same voltage. This is as per the national electric code.
> 


yes and no - If you ran romex in the conduit, you've got two layers of 
insulation. Is that the "permanent barrier" required by the code? Maybe?

And of course, the rotator and relay could be run with 300V insulation, 
just like the line voltage, and then you'd also be ok (although 
technically, you might need one of those funky boxes with a partition 
across the middle)


Quite a bit of Cat 5 wire is rated at much higher voltages than 300V.
Commscope 5nf5 flooded outdoor direct burial cat 5 cable is rated at 
1500VAC/2500DC

That roll of sprinkler control cable in the discount bin at Lowe's, 
maybe not.

There's also a lot of online code lawyers out there arguing about 
whether the exception below means the entire low voltage circuit has to 
be wired with Class 1 practices or just the part in the conduit.  This 
is a "consult Authority Having Jurisdiction" .

Or, claim it's a temporary installation with an extension cord in the 
pipe underground, not permanently connected, and therefore not subject 
to the NEC, any more than the extension cord running your holiday lighting.

it really boils down to "is it safe?"

Check out exception 1, (1):


800.133 2) Other Applications. Communications wires and cables shall be 
separated at least 50 mm (2 in.) from conductors of any electric light, 
power, Class 1, non–power-limited fire alarm, or medium-power 
network-powered broadband communications circuits.

Exception No. 1: Where either (1) all of the conductors of the electric 
light, power, Class 1, non–power-limited fire alarm, and medium-power 
network-powered broadband communications circuits are in a raceway or in 
metal-sheathed, metal-clad, nonmetallic-sheathed, Type AC, or Type UF 
cables, or (2) all of the conductors of communications circuits are 
encased in raceway.