cornytheclown wrote:

Home Builder wrote in message news:uMz2c.44391$Ri6.30603@lakeread04...

I'm working on a newly framed house with lots of 12-2 romex runs and
plenty of 24/4 wire low voltage runs to burglar alarm sensors at all
windows and doors. Yesterday I arranged for an insulation company to
foam the walls of this house. After the spray process was complete I
offered to help the foam installer trim the foam that had extruded
inside the face of each stud bay. While performing this task, I found
myself cutting into something a good deal harder than foam and realized
that I had managed to saw through one of the burglar alarm circuits that
had become embedded in the expanding foam and pushed outside of the wall
cavity. No problem! I had B-connectors and wire strippers in my
toolkit so I reconnected the circuit and immediately advised the
insulation mechanic to let me know IMMEDIATELY if he encountered (ie
inadvertently damaged) any wiring while trimming the excess foam. He
agreed and I was confident that everything would be ok.

This morning I decided to check all the burglar alarm circuits just for
grins and found a second circuit that had been severed albeit not by me.
The insulation installer, knowingly or unknowingly, had managed to
damage the second circuit, and then (knowingly or unknowingly) had
concealed the damage by spraying additional foam to cover the circuit!
I dug the damaged wires out of the foam and repaired the connections
quickly but I was left with a lingering fear that some of the romex
circuits could have been damaged as well. The insulation installer
could have sawed into a run of romex just enough to damage the
insulation without bothering to warn me about the damage, stuffed it
back into the wall like he did with the burglar alarm wire, and then
covered it with additional foam.

I wouldn't mind a completely cut romex circuit because I could fairly
easily test the entire electrical system before the drywall is taped and
floated and then remove sections of drywall and foam insulation to rerun
any severed cable. However, it would be damn near impossible to cut
completely through 12-2 romex with the type of blade used to trim foam
insulation. What this means is that any damaged would be confined to
the insulation. Very bad!

Why is it so difficult for building tradespeople to simply admit it when
they inadvertently cause or contribute to a problem instead of trying to
cover it up?

Is there a way to identify circuits with bad insulation without visual
inspection?


Well..the insulators dont want to hang around while you repair the
damage is the most likely reason they just cover up the mistakes. They
might get paid by the job and have another one to get too or they
simply dont want to hang around while someone fixes the
damage.........who know ???

What I cant understand is why with so many wires going into a house
today a person wouldnt use conduit in the walls that are being
insulated with the foam. It would make repairs or modifications down
the road a whole lot easier.... I know not all the wires...control and
fire/burgler alarm probably cant be 100 percent protected by
conduit.....but I would still get what I could in conduit if I was
filling the wall with foam insulation.

Conduit isn't appropriate for many situations. The aforementioned house
has roughly three runs of 1" conduit to every room for network wiring
(RG6 QS, cat 5E, etc) --- and each top plate had to be bolstered with
steel straps from stud to stud on each side of each hole... a process
that only partially restored the strength lost from the large conduit
hole and will eventually cause headaches for the sheetrock hangers. In
spite of the drawbacks, conduit is appropriate for network wiring
because network wiring changes every few years. NOT SO with romex.
It would be just plain dumb to run all romex through conduit in my
opinion because of the resulting loss of strength in the frame.


Lastly....Why were the wires not secured properly in the first place.

The wires were properly secured. As with conduit there is a trade-off
between various options when you're securing wire. For example, I like
to leave a loop of the 24/4 wire in the wall next to all burglar alarm
switches. Why? Because switches could eventually fail and the loop of
wire allows future repairs to be completed without re-running the wire.
Suppose a switch fails. You pull the bad switch out of the hole,
clip the leads, reconnect a new switch, and stuff the new switch down
into the same hole. This requires at least six inches of slack IMHO
which is more than enough to get pushed outside the stud bay and damaged
if the foam installer isn't careful. There were roughly 40 burglar
alarm circuits in the aforementioned house, and most of them survived
the foam. Two were damaged and were easily repaired. Yet the loops are
still in the wall to facilitate future repairs. Now what's better?
Spending a couple of minutes to repair two damaged circuits in order to
facilitate future repair work? Or stapling down the wire so thoroughly
that there is NO SLACK WHATSOEVER... thereby forcing the homeowner to
rip out the wall or run new wire if/when a switch fails?

If I were facing the prospect of stapling low voltage wire every four or
five inches, running conduit for all romex, etc, etc, as you suggest, I
would find a better solution: Hire foam installers who will NOTIFY ME
if/when they damage a cable or a wire so that I can fix it. It only
takes a couple of seconds to flag a damaged wire, and it would only take
me a couple of minutes to fix it --- a lot LESS time than it would take
to install a single run of conduit, staple low voltage wiring every four
or five inches, or staple ALL runs of romex so throughly that it would
be totally impossible for an inattentive foam installer to damage any
cables.

I have never seen wires run by professionals in a matter where you
could pull it out past the face of the stud bay ???

That's odd. I've never before encounted a professional who has NOT seen
this. :-) It's especially common in situations where the electrician
may have run the romex down a partially exposed wall channel where it's
difficult to staple adequately. There aren't many tasks in construction
that you can throughly idiot proof ANY stage of the construction process
and this is no exception. For less money than it would cost to install
conduit for romex I could hire off-duty cops with sidearms to watch the
foam installers and stop them immediately if they damage a cable and
attempt to conceal it.

surely they
stapled the romex to the studs and at least used some kind of
insulated fastener for the control or alarm wires.

Surely!

Thanks for the criticism, but you didn't answer my question.