[Amps] 230v wiring question

[Jim Brown]

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