On Sat, 17 Sep 2011 06:32:50 -0700 (PDT), "
wrote:

On Sep 16, 8:42Â*pm, wrote:
On Fri, 16 Sep 2011 07:15:33 -0400, Doug Miller





wrote:
On 9/16/2011 6:01 AM, Andy wrote:

Â* Â*The neutral (white) wire is not phase sensitive, so it can come
from
anywhere. Â* However, it will NOT meet code, if that is a concern...

It's not just a question of whether it meets Code or not. This is also a
safety issue. What you propose is dangerous:

The neutral conductor carries the same current as the hot conductor.
When two circuits are cross-connected to use the same neutral, the
current in the neutral is the *sum* of the currents in the two hot legs.
A current of 15 amps in each of two hot legs will result in a 30A
current in the neutral. This risks a fire.

Also, someone working on one circuit and not knowing that the neutral
carries current from a different circuit could receive a fatal shock
from that neutral -- how would he know to shut down both circuits?

Â* It is illegal - but in the case he's speeking of, NOT necessarily
dangerous. The neutral is only required to activate the x10 switch. It
is NOT a load neutral Â*3 connections on the X10 device' Line in , Line
out, and neutral. The neutral is only used by the control circuit -
which is a voltage controlled switch - not current controlled (think
j-fet vs bipolar transistor) -- Hide quoted text -

- Show quoted text -

That switch itself is in fact a load. A very small one, but it's
still a load. If it did not pass current on the neutral, then it
would not need the neutral. Could it deliver a serious shock
as is? I would agree that it would not, provided everything
else is wired correctly, meaning there is no disconnected
neutral on the other circuit, etc. But it could cause future
problems where someone later comes along and sees
that neutral, assumes it is on the same ciruit as the hot
and decides they want to use it for something
else, like adding more outlets, causing an overload.
That is the serious risk you run when you decide to
ignore a code rule that is universally followed by
almost everyone.
If, as I suspect, the switching mechanism in the X10 is a voltage
controlled switch (think FET or MOSFET device) there is NO current
flow to the neutral.

Howver, you HAVE identified the danger - the POSSIBLE FUTURE danger
which makes it illegal and unadviseable to use the "split neutral"
configuration. The FACT that the orphan neutral is in the box makes it
POSSIBLE for some future person (or even the OP, in the future) to use
that neutral to complete the circuit for a REAL load, such as an
aditional outlet or lamp. Since it is APPARENTLY possible to bring a
neutral up from below, the much better way to approach this is to
bring a FRESH CIRCUIT up from below to power this.