>>>READER-TO-READER QUESTIONS AND ANSWERS
that must be gently pressed back with
a small screwdriver or other tool to
allow the circuit to be fully pushed in
to the GFCI housing.
All GFCI receptacles work by
detecting an imbalance of current on
the hot and neutral wires. You can
create the imbalance by wiring the
input to the GFCI with the hot wire
connected to the LINE terminal and
the neutral wire connected to the
LOAD terminal, and plugging the
pump into the receptacle. That way,
when the pump turns on, current
flows through the GFCI circuit on the
hot wire, but bypasses the circuit
on the neutral wire, so an imbalance
is created. Normally, that would
energize a solenoid in the GFCI and
open the circuit, but your modification
prevents that. Instead, the LED lights,
and stays lit until the pump turns off.
The wiring in GFCIs can differ
between models or manufacturers, so
you will need to determine how yours
is wired. A representative example can
be seen on page 5 at: http://www.fair
Installing a modified GFCI in
permanent branch circuit wiring
would violate electrical code. Instead,
install your modified GFCI in a project
box or electrical junction box that is
wired as an extension cord.
[#10083 - October 2008]
I have an X10 lighting system in my
home that used to work flawlessly,
using X10’s “Active Home” software to
control the yard lights. Over the last
year, some zones work intermittently
and some not at all. I’ve tried to
find any electrically noisy appliances
that may be on when the system
gets flakey, but have not seen any
consistent pattern that might be
causing the problem. I do know that
the new pump motor for the pool
equipment creates problems when it’s
on, but it shuts off hours before the
lights come on (or try to).
#1 I doubt the pool pump is to
blame — it uses a capacitor-start single-phase AC induction motor which may
dim the lights briefly when fired up
96 December 2008
(much as heat pumps, A/C, electric
dryers, or any other heavy current
load would). A large motor may cause
a single brief power line glitch when
up to speed and the start-winding cuts
out (usually within five seconds
If you have (or can borrow)
another X- 10 transmitter, try to isolate
the problem to the Tx, Rx, or the
PC running the HA software. Have
you moved the place where the
transmitter plugs in to the house
wiring? Did any home remodeling or
electrical work shift the wiring in the
The transmitter and X- 10 controllers must be on the same “leg” or
phase of the AC wiring (i.e., L1 or L2),
preferably on the same branch circuit
(breaker) for reliable communication
over the power line.
#2 The first thing I would check is
the interface from your computer.
See if there is another port on your
computer with which you can connect
to the interface. Or try to borrow
another interface — it may have been
killed by a power line spike. Where I
live, we get lightning with storms
that can kill electronics systems. Try
reloading the Active Home software.
Next: Have you changed operating systems on the computer (XP to
Vista)? If you have, try reloading the
If you have a wireless Internet
server, it can cause some interference
problems. Try turning off the wireless
part of it. My Netgear WGR614 can
cause interference with cell phones
and has the ability to enable or disable
the wireless function.
#3 Sometimes the saved Active
Home (AH) files become corrupted.
My bedroom lights would randomly
turn on at different times every night!
When I destroyed my saved AH files
and rebuilt them from scratch, the
problem went away.
Also, I'd like to recommend trying
a couple products that have given
me consistent and reliable X10
communication signaling in my house
without any weird shenanigans.
PZZ01 Blocking Coupler. Keeps
your X10 signals inside your house
and keeps your neighbor's signals out.
Plug-In Phase Coupler. Some of
these devices plug directly into the
220 VAC outlet meant for your clothes
dryer and have a pass-through design
so you can still plug in your dryer.
#4 In most homes, power is brought
in to the house via a center tapped
transformer on the street. The outer
terminals provide 240V for the stove
and dryer and the center tap provides
the neutral which gives you two
phases of 120V for everything else. In
the X10 system, your transmitter will
transmit the signals on whatever phase
it is plugged into. It can easily talk to
other X10 devices on the same phase
wire but in order to talk to devices on
the other phase, the signal needs to go
all the way back through the transformer on the street to be coupled to
the other phase.
This can severely attenuate the
signal, resulting in unreliable operation
of X10 devices not on the same phase
wire. My guess is that the poor signal
quality on the other phase results in
X10 devices that work intermittently.
The easiest way to test this is to wait
until you are experiencing problems
and then turn on your electric oven.
The large 240V element in the oven
will act as a resistor across the two
phases. This should allow the signal
from X10 to pass easily from one side
to the other. If after turning on your
oven, all the X10 devices work
perfectly, then you have a phase
The permanent solution to this is to
insert a 0.1 micro farad capacitor
across the 240V stove breaker in your
electrical panel. Make sure you turn
off the main power before doing this
and make sure to use a capacitor that
is rated for AC and "Across the line"
use. The capacitor that I used was
Digi-Key part number P10523-ND.