Re: Outside plant - prewire customer demarc preference

[Brandon Martin <lists.nanog () monmotha net>]

On 12/1/23 05:18, Josh Luthman wrote:
> Keep in mind new construction versus having to get around drywall.

Rigid conduit is great if you can get it.  If you can, by all means go 
for it!

However, if the outside utility aggregation point is not pretty much on 
the other side of the wall from the inside media aggregation point, 
rigid conduit can be a pain even in new construction.

Outside of a few select areas (Chicago, parts of NYC) where it's 
required even in stick-built residential construction for electrical 
wires (and then it's usually metal, not plastic), most residential 
electricians almost never use it aside from maybe a short run between 
the meter base and panel - generally right on the other side of the wall 
from each other.

If the path is complicated, you end up having to piece together fittings 
to make the path up and keep proper sweep, and of course you can't 
feasibly get it horizontally into stud framed walls at all unless you 
can poke it in from the edge which involves an otherwise unnecessary 
hole in the corner board or you resort to cutting it into 16" pieces and 
putting it back together with couplers.  You can surface mount it to the 
bottom of floor joists, for example, but then you can't drywall that 
ceiling without building out a chase.

Corrugated plastic conduit like ENT or comm duct can be pulled in 
essentially like NM cable (Romex).  It's easy, fast, and it's a process 
essentially all resi electricians are familiar and comfortable with.

I'm thinking mostly SFU construction here, but a lot of the same 
concerns apply to MDUs as well.  The 4-over style wood framed buildings 
that have become popular are generally wired in NM and SE cable. 
There's often no good path for a rigid conduit with proper sweep to 
every unit.  Flexible/corrugated duct is just a lot more, well, flexible.

> 2" is beyond excessive.  We use 1.25" duct for our 288ct *PLUS* up to 6 
> flat drop cables.

I agree in principle, but it allows for plenty of room for multiple 
utilities to get in without worrying about tearing up the others' 
cables.  If it's just poking through a wall, you're talking, what 8" of 
pipe?

--
Brandon Martin
Mothic Technologies
317-565-1357 x7000