Yawn,
Romex is a trade name of ROME Wire and Cable it is colloquially utilized to
specify NON-Metallic Cable. The guy asking the question already called the
wire ROMEX and I stated it is a trade name for non-metallic cable as there
are International members also here to clarify.
Jim, If you have cable running through your house in California with
Non-Metallic cable with a black, white and a bare ground wire running
through it covered in plastic with a paper covering on the ground... That's
what he was calling ROMEX. It is manufactured by a Zillion companies now,
Rome was the first. Not to be confused with UF which is gray and has no
paper used for UNDERGROUND FEEDER (UF) NON-Metallic was all white until a
couple years ago, and now they color it to specify the ampacity of the wire
(Wire Gauge) to avoid mistakes.
Anyway, Romex type cabling Does Not specify the ground as a conductor...
12/2 has three wires. 12/3 has four.
Since the ground is not a current carrying conductor it is not counted. It
also doesn't have to be green.
Yes many localities specify ABOVE THE NATIONAL ELECTRIC CODE. For years
Greenfield was allowed to self ground, not any more, you need to pull a
ground through the tube. As you say, some municipalities specify a ground
with conduit. I myself think that is overkill, but I'm sure they've seen
old rusted through corroded pipe everywhere in that old city. In my opinion
if the pipe is rotted through, it's not long before all the wires will be
getting pulled apart anyway... You can't protect everyone from every
situation.
The bad thing about pulling a ground is you lose one conductor per conduit.
And there are maximums you can pull for various sizes. Many people think
you can stuff away, NOPE. Boxes too, maximum wire counts.
Just like The NEC says you can use OO wire in a 200 Amp Power service in
residential, even though it is only rated for 195AMPS. St Louis (Ill Side)
for instance says Nope you must use OOO cable in the same service even
though the wire is now rated for 225Amps.
I worked as an electrician in the Minneapolis area so have all their Quirks
memorized from 15 years ago. Now living in Sioux Falls, but only wiring for
my own home these days, I had to learn all the new crap...
Arc Fault Breakers are a nice new thing to get used to. Change your power
service here and you need to bring your whole house up to current NEC, with
local quirks.
Troubled by the last comment... That was taping the conductors. In
commercial 3 phase wiring you do that all the time, get the tape out and
wrap phases to indicate which is which. This becomes very important with
HIGH LEGS and for motor rotations.
When looking in a box or a panel the wires need to be correctly colored. If
you have a white wire carrying HOT you need to tape the exposed white
adequately to indicate it is truly a hot wire. In big commercial installs
most wires are BLACK, you tape to identify what they are.
Bares are always grounds and don't need to be green, however... If you were
using a black wire as a ground (done in commercial installs all the time),
you tape it green.
My tape box has all the colors in it.
So on both ends of a romex 220 line you tape around the white wire
adequately to indicate it is a black wire and not a neutral. Completely
Kosher. The ground doesn't have to be taped green as it is obviously a
ground. That's residential only BTW...
Have a nice night,
BOB DD
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
Behalf Of Jim Brown
Sent: Tuesday, April 24, 2007 7:21 PM
To: amps@contesting.com
Subject: Re: [Amps] 230v wiring question
On Tue, 24 Apr 2007 14:36:02 -0500, Robert Bonner wrote:
>Romex is trade name of a non-metalic cable. His 12/2 is 2 conductors and a
>bare ground.
As a member of several international EMail reflectors and international
standards committees, I have learned that it is folly to assume that all of
the
members know trade names of products that are regional in their use. I spent
the
last 42 years of my professional life in Chicago, where stuff like what you
describe as Romex is illegal, and I dunno nuthin about it. I've never used
it or
anything like it, and had never seen it in houses until I moved to
California
last year (where it is called something else).
12-2 describes a pair of #12 conductors. A cable with three #12's is 12-3.
Thus
my advice that there must somehow be a third conductor for the safety
ground.
And I'm sticking to it. :) If this stuff called Romex has a third conductor
for
ground, that's fine!
In many jurisdictions, including Chicago, steel conduit can be used as the
safety ground, and usually is. Many other jurisdictions say that conduit is
not
enough (because if improperly installed the continuity can be degraded over
time
( and require that you have a dedicated green wire inside the conduit.
>It is good for 120 V wiring and in the USA if you black or red
>tape the exposed white conductor you can use it as a hot and wire up 220V.
I'm troubled by this last comment. The ground wire MUST be coded green
whenever
it is identified. If you're using the cable you've described for 240 volts,
the
paired wires must be used for the two 240 pair, and the bare wire must be
the
safety ground. If you're using that cable for 120 volts, the pair must be
120V
hot and neutral, and the bare wire still must be the safety ground. But you
CANNOT use only that three conductor cable for BOTH 240V and 120V
simultaneously, because the ground CANNOT be used as a current carrying
conductor.
Another point. Twisted pair cable inherently rejects noise and RFI. Steel
conduit inherently shields the wiring inside it. The unshielded parallel
wire
power wiring in my CA house radiates far more noise and receives far more RF
than did the wiring in my Chicago house that is in steel conduit. As a
result, I
have more RFI issues here in CA with antennas 150-200 ft from my house than
I
did in Chicago with antennas 15 feet from my house.
73,
Jim Brown K9YC
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