I think the testing protocol works because the antenna is wrapped around
one of the hot wires and is also grounded. As the antenna detects
current FLOW when the utility power is on line, you "fool" it into
believing the line is dead by opening the main breaker. (Remember, this
is not for an interlock type setup, but rather a transfer panel)
Since with the transfer panel you will only be energizing certain
circuits, the other breakers are closed as is the Main when the power
goes out. When utility power is restored, there will be flow that is
detected by the antenna and...
Neat little device.
I don't think so. I think it detects the presence of voltage, not current,
regardless of what it says. Otherwise it would be of no use to many
transfer switches which disconnect the utility completely and put the
generator in its place.
wait: see, I was right!
"When the power indicator wire senses an electromagnetic field from a
voltage at the supply wire, the power indicator provides an appropriate
audio and/or visual alert signaling that primary power is available at the
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learn more about Jesus
Not sure what the link says as I couldn't get it to open but the
electromagnetic field to which you refer above is due to the flow of
current through the line. That voltage is present when the main breaker
is open but only flowing when it's closed. In the test mode there is no
signal until the main breaker is closed.
I think you're correct about any transfer switch that totally
disconnects the home from the grid. However, those are, AFAIK, all
automatic transfer switches and automatically put the house back on the
grid and kill the generator when power returns.
On 2/1/2015 9:30 PM, Unquestionably Confused wrote:
Disregard my last. Went to Reliance's site and pulled their product
sheet. See the following (and remember, this applies AFTER INSTALLATION
when the unit is being used as intended)
To Activate: Switch the main breaker to the OFF position. Turn the
PowerBACK switch to the ON position. The green “System Armed” light will
illuminate. When power returns to the panelboard, a 100dB alert will
sound. Return main breaker to ON position and switch the PowerBACK to
the OFF position.
no, it is present when there is voltage regardless of current flow. Haven't
you ever used one of these?:
That voltage is present when the main breaker
no, there are manual switches like this as well:
On Sunday, February 1, 2015 at 10:30:53 PM UTC-5, Unquestionably Confused wrote:
I agree with your position on how it works. I'd only point out
that the above description doesn't really prove anything one way or
the other. You have an EMF field from an energized conductor without
current flowing. You have a different field with current flowing.
The question is, which is it designed to detect? I thought it was
detecting the former, that's why the test instructions made no sense.
If, as you say, they are looking for current flow into the house
in the circuits left connected to the utility, then the instructions
make perfect sense.
I've seen whole house transfer switches for use with a generator
that were manual.
that is exactly the right question...
there are 2 kinds of fields, electric and magnetic.
if the sensor wire does not make a complete loop, i.e if it wraps around th
e panel conductor but connects into the senser electronics with only one co
nnection, i.e. it wraps around but does not make a complete loop, then it i
s an electric field sensor and will pick up the voltage without any current
Think of it as a small capacitor that senser the voltage.
to be a magnetic field sensor, the sensor wire would have to be a complete
circuit that loops back into the sensor device. like a clamp on current me
from the description, it sounds like it is an electic field voltage sensor,
not a current sensor
and an electric sensor would be useful to detect that the grid is back on,
even if your interlock switch has you disconnected from the grid and you dr
aw no current
When they call it an electromagnetic field they are muddying the
waters, because without current flow there is no "electromagnetic
field" as it is generally described. It senses a low frequency
electrical emission - kind of like a 60hz "radio transmission" -
technically I guess an electomagnetic phenomenon -
On Sunday, February 1, 2015 at 7:33:27 PM UTC-5, Pico Rico wrote:
I believe UC has it figued out correctly an it won't work with anything
that disconnects all loads.
The question is what EMF it's detecting. UC believes it's designed to detect
the EMF when current is flowing. You believe, as I did, that it's detecting
an electric field from just voltage. The current approach is consistent
with the testing procedure
in the install instructions. From the test procedure, the alarm sounds
when the main breaker is closed, ie in normal operation. And it specifically
says the alarm will go off when the main breaker is *open*. That sure
indicates to me that it works like UC says, ie it's looking for current
flow in the service conductors. With an install that separates only some of
the circuits off to a generator, when power is restored, you'd have
current flowing again in the service conductors to whatever other loads
there are in the house. It senses that and turns the alarm on. Open
the main breaker, as described in the test procedure, the current flow
stops and the alarm goes off.
I agree having it sense voltage would make more sense and make it
far more useful. That's what I
thought it did. But if it works that way, something is very wrong with
step #2 in the install instructions, which clearly say opening the main
breaker, with utility power present, silences the alarm. If it works
like you think, opening the main would have no effect.
It seems that the only thing all of us can agree on is that the manual
or test info is somewhat confusing.
A suggestion... Several years back I installed the transfer panel
manufactured by Reliance (works like a charm, by the way) and had a
question. This was on a Saturday and I dropped them a note on their
website. Believe it or not, I had a response later that afternoon that
explained exactly and clearly the answer to my question.
That's not the real story, however. Monday morning I received a call
from the company's president who was inquiring to ensure my issue had
been resolved and asked if there was anything else I needed. Now THAT's
customer service. I suspect that if anyone is still interested in how
this detector works, a phone call to Reliance will put you on the line
with somebody who can tell you everything you want to know and more.
On Monday, February 2, 2015 at 8:52:43 AM UTC-5, Unquestionably Confused wrote:
The test isn't confusing if it works like you, and now I, think
it does. The manual should have a paragraph that describes what
it senses, how it works. That would eliminate confusion, people
buying it for the wrong application.
For me, the key here, besides that it fits the test, is that it
says it's for installation where there is a generator transfer panel
or generator ready main panel. As you pointed out, with either of
those, there are typically circuits that are connected to either
the generator or the utility and some circuits that are connected
only to the utility.
On Sun, 01 Feb 2015 18:21:02 -0600, Unquestionably Confused
Ir does not sense current flow, because there IS none with the main
switch open. It senses voltage on the line wire. when voltage comes
on, it rings the alarm telling you it is safe to transfer back to
mains power (and shut off the alarm)
Definitely the simplest way to determine when the power comes back on
- and the cheapest code compliant way of doing it. (not code compliant
to have anything electrically connected ahead of the mains
On Sunday, February 1, 2015 at 7:21:13 PM UTC-5, Unquestionably Confused wrote:
We have a winner! I think you're correct. I was thinking of using it
with an interlock type setup, but the description says manual transfer
switch or generator ready load center. So, as you describe, it does
work the opposite of how I thought it works. It depends on current
flowing through the service conductors when power is restored. If
you use it on any setup where there is no load on the utility when
power is restored, eg you have the main breaker open, are using a
interlock on the main panel, etc, it won't work.
Yes, for certain applications. But it's useless if you use an interlock.
Also not as good if you have no generator at all and just want to know
when power comes back. Some times with power outages that are expected
to be short, I like to open the main breaker so that I can put the power
back on after it's back for 5 mins and I see it's stable. Avoiding
possible surge on restoration, or it coming back on at half-power, etc.
Having an alarm that would work for that would be cool. You could use
this one and open up all the critical breakers on important stuff, just
leave one light circuit on and I guess that's not so bad, just flipping
a lot of breakers instead of one.
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