GFI question
 

I have a dedicated 20 amp line for my pool. I have a GFI outlet by the deck
for the filter. I want to install a single pole switch in the house to turn
the filter on and off from inside. If I install a switch, will the GFI trip
everytime you turn the power off to the GFI?

GFI question
 

On Wed, 09 May 2007 01:49:56 GMT, "gntry" wrote:

I have a dedicated 20 amp line for my pool. I have a GFI outlet by the deck
for the filter. I want to install a single pole switch in the house to turn
the filter on and off from inside. If I install a switch, will the GFI trip
everytime you turn the power off to the GFI?


Why should switching power to a GFI trip it? A GFI works on difference
on current flowing in 2 parts of the circuit. Both are being started
and stopped at exactly the same time.

My holiday light setup involved a GFI that was switched like that, I
used if for about 40 days, and had not one trip that occurred when it
was being switched.
--
Mark Lloyd
http://notstupid.laughingsquid.com

"DISCLAIMER If you find a posting or message
from me offensive, inappropriate, or disruptive,
please ignore it. If you don't know how to
ignore a posting, complain to me and I will
demonstrate."

GFI question
 

Why should switching power to a GFI trip it? A GFI works on difference
on current flowing in 2 parts of the circuit. Both are being started
and stopped at exactly the same time.

My holiday light setup involved a GFI that was switched like that, I
used if for about 40 days, and had not one trip that occurred when it
was being switched.


Quite correct.

BUT a un-powered GFCI can permit some safe hazards to continue.

It is better to have the GFCI always powered and have the switch AFTER the
GFCI.

A powered GFCI will detect and "trip" a "fault" between neutral and ground.

A GFCI will NOT detect incorrect wiring whereby neutral and HOT are
switched. But a powered up GFCI will still trip when either of the two
load wires have a 5ma path to ground.

A further advantage of putting the GFCI before the switch is that it will be
indoors and less subject to contamination from aerosols.

Regardless, it's a GOOD idea to TEST the devices. They DO fail and outside
units fail more often. And they don't necessarily fail "safe."

GFI question
 

Mark Lloyd wrote:

Why should switching power to a GFI trip it? A GFI works on difference
on current flowing in 2 parts of the circuit. Both are being started
and stopped at exactly the same time.

I have two plug in GFI devices and they sometimes trip after a power
outage. A friend of my had some GFI outlets in his garage do the
same thing. I have NO idea why it happens but it does happen.
--
I don't understand why they make gourmet cat foods. I have
known many cats in my life and none of them were gourmets.
They were all gourmands!

GFI question
 

gntry wrote:
I have a dedicated 20 amp line for my pool. I have a GFI outlet by
the deck for the filter. I want to install a single pole switch in
the house to turn the filter on and off from inside. If I install a
switch, will the GFI trip everytime you turn the power off to the GFI?

Not in my experience. I have a couple in the shop, one on the air
compressor, plugged into the GFCI and then to the switch. Turning off the
switch lets the GFI drop out. NBD since it's right next to the compressor,
but it's not really "right". It should be the other way around; GFCI, then
switch, then compressor.
Same for the one on my workbench, though it's seldom without power unless
I trip a breaker to work on something.

I've heard others say no, they don't drop out before, but I haven't yet
found one myself that didn't, nor anyone whose story about same seemed
believable. From what I've seen of GFI designs on the 'net, they operate on
a "latch" system and that "latch" drops when the ac goes away. You always
have to press the button to let power thru a GFI when they're new also,
according to those, so that seems to support my own experience. It might
have been wikipedia; not sure.

HTH
Pop`

GFI question
 

I've heard others say no, they don't drop out before, but I haven't yet
found one myself that didn't, nor anyone whose story about same seemed
believable. From what I've seen of GFI designs on the 'net, they operate
on
a "latch" system and that "latch" drops when the ac goes away.

I would like to see a URL to that design.

The designs I have seen "on the net" and my own experience are that the GFCI
contacts stay closed when the input power goes away.

You always
have to press the button to let power thru a GFI when they're new also,
according to those, so that seems to support my own experience. It might
have been wikipedia; not sure.

It definitely would be a good idea to "ship" with the device already
tripped. They will not reset without power being present. If it is wired
backwards (load and line switched) and pre-tripped, it will never pass
current (which is good.)

GFI question
 

John Gilmer wrote:
I've heard others say no, they don't drop out before, but I haven't
yet found one myself that didn't, nor anyone whose story about same
seemed believable. From what I've seen of GFI designs on the 'net,
they operate on a "latch" system and that "latch" drops when the ac
goes away.

I would like to see a URL to that design.

Well, you'll have to stop by here or go to one of our local places. They
have the UL/CSA/EC MRUs and all that crap on them, along with the standard
safety specs.

Interesting ...

Pop`



The designs I have seen "on the net" and my own experience are that
the GFCI contacts stay closed when the input power goes away.

You always
have to press the button to let power thru a GFI when they're new
also, according to those, so that seems to support my own
experience. It might have been wikipedia; not sure.

It definitely would be a good idea to "ship" with the device already
tripped. They will not reset without power being present. If it
is wired backwards (load and line switched) and pre-tripped, it will
never pass current (which is good.)

GFI question
 

John Gilmer wrote:
I've heard others say no, they don't drop out before, but I haven't
yet found one myself that didn't, nor anyone whose story about same
seemed believable. From what I've seen of GFI designs on the 'net,
they operate on a "latch" system and that "latch" drops when the ac
goes away.

I would like to see a URL to that design.

Oops, misread that. Try these:
http://www.osha.gov/SLTC/smallbusiness/sec14.html

Lots of other, better links too if you bother to try.

Pop`



The designs I have seen "on the net" and my own experience are that
the GFCI contacts stay closed when the input power goes away.

You always
have to press the button to let power thru a GFI when they're new
also, according to those, so that seems to support my own
experience. It might have been wikipedia; not sure.

It definitely would be a good idea to "ship" with the device already
tripped. They will not reset without power being present. If it
is wired backwards (load and line switched) and pre-tripped, it will
never pass current (which is good.)

GFI question
 

On Wed, 9 May 2007 09:19:05 -0300, "John Gilmer"
wrote:



Why should switching power to a GFI trip it? A GFI works on difference
on current flowing in 2 parts of the circuit. Both are being started
and stopped at exactly the same time.

My holiday light setup involved a GFI that was switched like that, I
used if for about 40 days, and had not one trip that occurred when it
was being switched.


Quite correct.

BUT a un-powered GFCI can permit some safe hazards to continue.

It is better to have the GFCI always powered and have the switch AFTER the
GFCI.

A powered GFCI will detect and "trip" a "fault" between neutral and ground.

A GFCI will NOT detect incorrect wiring whereby neutral and HOT are
switched. But a powered up GFCI will still trip when either of the two
load wires have a 5ma path to ground.


I wired them that way, so the GFCI would also be a switched
receptacle. The other way (switch after GFCI) would require adding a
second receptacle.

A further advantage of putting the GFCI before the switch is that it will be
indoors and less subject to contamination from aerosols.

Regardless, it's a GOOD idea to TEST the devices. They DO fail and outside
units fail more often. And they don't necessarily fail "safe."


Why assume it's outside? My switch and GFCI were both inside.
--
Mark Lloyd
http://notstupid.laughingsquid.com

"DISCLAIMER If you find a posting or message
from me offensive, inappropriate, or disruptive,
please ignore it. If you don't know how to
ignore a posting, complain to me and I will
demonstrate."

GFI question
 

Mark Lloyd writes:

Why should switching power to a GFI trip it? A GFI works on difference
on current flowing in 2 parts of the circuit. Both are being started
and stopped at exactly the same time.

I have a portable GFI that's intended to be used with extension cords or
portable tools. It's in the form of a 15 A extension cord (male plug on
one end, female socket on the other) with a GFI in between. It drops
out any time the input power is lost. You have to "reset" it initially
whenever you plug it into a new power source.

I assume this is a safety feature - you don't really want a power tool
restarting on its own after it has stopped because the line power went
away. So some GFIs do drop out on power loss, just like a magnetic
starting switch for a large power tool.

On the other hand, the wall-outlet type of GFI does not trip on power
loss. It behaves more like a circuit breaker.

Dave

GFI question
 

"John Gilmer" writes:

I've heard others say no, they don't drop out before, but I haven't yet
found one myself that didn't, nor anyone whose story about same seemed
believable. From what I've seen of GFI designs on the 'net, they operate
on
a "latch" system and that "latch" drops when the ac goes away.

I would like to see a URL to that design.

The designs I have seen "on the net" and my own experience are that the GFCI
contacts stay closed when the input power goes away.

I have both types.

There's a portable GFI which is part of a short extension cord. It
seems to use a relay to pass current; the relay drops out when input
power goes away. The Reset button has to be pressed after the unit is
plugged into a live outlet to get it to pass power.

Then there are the wall-outlet GFIs. They work approximately like a
breaker, mechanically latched in the ON state and electrically tripped
when the monitoring circuit detects a ground fault.

So both exist.

Dave

GFI question
 

I have both types.

There's a portable GFI which is part of a short extension cord. It
seems to use a relay to pass current; the relay drops out when input
power goes away. The Reset button has to be pressed after the unit is
plugged into a live outlet to get it to pass power.

I don't have a GFCI extension cord. But I do have some appliances (window
A/C and hair dryer) that have GFCIs as part of the plug assembly. Neither
of these needs to be reset when the power goes out.


Then there are the wall-outlet GFIs. They work approximately like a
breaker, mechanically latched in the ON state and electrically tripped
when the monitoring circuit detects a ground fault.

So both exist.

Dave

GFI question
 

gntry wrote:
I have a dedicated 20 amp line for my pool. I have a GFI outlet by the deck
for the filter. I want to install a single pole switch in the house to turn
the filter on and off from inside. If I install a switch, will the GFI trip
everytime you turn the power off to the GFI?

www.gfi.com

GFI question
 

Nguy n Thanh Tu n wrote:
gntry wrote:

I have a dedicated 20 amp line for my pool. I have a GFI outlet by the deck
for the filter. I want to install a single pole switch in the house to turn
the filter on and off from inside. If I install a switch, will the GFI trip
everytime you turn the power off to the GFI?


www.gfi.com

Hi,
No. An exmple. Bathrooms are GFI protected. Turning lights on/off
in the bathroom does not trip breaker. There are GFI outlet and GFI
breaker.

GFI question
 

Tony Hwang wrote:
Nguy n Thanh Tu n wrote:
gntry wrote:

I have a dedicated 20 amp line for my pool. I have a GFI outlet by
the deck
for the filter. I want to install a single pole switch in the house
to turn
the filter on and off from inside. If I install a switch, will the
GFI trip
everytime you turn the power off to the GFI?


www.gfi.com

Hi,
No. An exmple. Bathrooms are GFI protected. Turning lights on/off
in the bathroom does not trip breaker. There are GFI outlet and GFI
breaker.

Note that in houses wired according to code, the GFI-protected outlets
in the bathroom are on a different circuit from the bathroom lighting.
Nevertheless, Tony is correct; the GFI will not trip if you wire the
switch into the circuit. Make *very* sure you wire the switch in the hot
line, not the neutral line.

Yours aye,
W. Underhill

--
"Take sides! Always take sides! You may sometimes be wrong - but the man
who refuses to take sides must *always* be wrong! Heaven save us from
poltroons who fear to make a choice!" R.A. Heinlein, "Double Star"