J
Jim Howe
I am replacing all the circuitry for outlets in the bedrooms of my house,
as well as living room, family room and office. I am going to put all the
new circuits which supply outlets in these rooms on Arc Fault Interrupter
breakers. My house was built in 1910.
The house has two buses of 95 year old pipe and post wiring, one bus runs the
length of the attic (the 'attic bus') and the other runs the length of the
house within the second floor joists (the 'second floor bus').
The attic bus and second floor bus are wired in parallel and have for many
years been connected to a 15 amp breaker in the load center. The attic
bus supplied second floor ceiling lights and second floor outlets; the
second floor bus supplies three ceiling lights on the first floor.
All of the loads on the attic bus are disconnected. The second floor bus
has three loads - all are switched ceiling lights, two have relatively modern,
albeit over 30 year-old silent toggle switches and the third has an antique
push-button device from years gone by.
I decided that as an interim I might put this pipe and post wiring on an AFI
breaker, to help deal with any possible loose connections. I was baffled to
discover that when I came upstairs after making that change in the load center
that upon turning on one of the first-floor ceiling lights (powered by the second
floor bus) that the AFI breaker cut out after perhaps 250 to 500 milliseconds. By
the way I have tried this with both of the toggle-type wall switches but not
with the push-button antique switch. I also did not try turning on the light before
turning on the breaker.
So I went back to the standard 15 amp breaker for this pipe and post wiring, because
as far as I can remember (having lived here 31 years) the joint hasn't burned
down even once yet!
Is it possible that some arcing in a wall switch might trigger an AFI breaker to
drop out? This does not seem physically plausable - arcing should occur mostly
on the breaking of a connection rather than on the making of a connection, I think.
I wonder if the nature of pipe and post wiring might interfere with the function
of an AFI breaker - because the two conductors are separated by about 12 inches
as they go around the house, transients might behave differently on this kind
of wiring as compared to romex cable. But this explanation also seems like something
of a stretch to me, a grasping at straws, a bit far fetched!
I would like to know if this is something that any others have experienced. By the
way I have tried two different, brand new AFI breakers and both behaved exactly
the same - there is definitely something that they do not like about that circuit
or its wiring. Also by the way the breakers are QO type but have the green test
buttons and so are not affected by the recent recall of Square-D AFI breakers.
Baffled, but keeping crossed fingers crossed, in Portland, Oregon - Jim Howe
....
as well as living room, family room and office. I am going to put all the
new circuits which supply outlets in these rooms on Arc Fault Interrupter
breakers. My house was built in 1910.
The house has two buses of 95 year old pipe and post wiring, one bus runs the
length of the attic (the 'attic bus') and the other runs the length of the
house within the second floor joists (the 'second floor bus').
The attic bus and second floor bus are wired in parallel and have for many
years been connected to a 15 amp breaker in the load center. The attic
bus supplied second floor ceiling lights and second floor outlets; the
second floor bus supplies three ceiling lights on the first floor.
All of the loads on the attic bus are disconnected. The second floor bus
has three loads - all are switched ceiling lights, two have relatively modern,
albeit over 30 year-old silent toggle switches and the third has an antique
push-button device from years gone by.
I decided that as an interim I might put this pipe and post wiring on an AFI
breaker, to help deal with any possible loose connections. I was baffled to
discover that when I came upstairs after making that change in the load center
that upon turning on one of the first-floor ceiling lights (powered by the second
floor bus) that the AFI breaker cut out after perhaps 250 to 500 milliseconds. By
the way I have tried this with both of the toggle-type wall switches but not
with the push-button antique switch. I also did not try turning on the light before
turning on the breaker.
So I went back to the standard 15 amp breaker for this pipe and post wiring, because
as far as I can remember (having lived here 31 years) the joint hasn't burned
down even once yet!
Is it possible that some arcing in a wall switch might trigger an AFI breaker to
drop out? This does not seem physically plausable - arcing should occur mostly
on the breaking of a connection rather than on the making of a connection, I think.
I wonder if the nature of pipe and post wiring might interfere with the function
of an AFI breaker - because the two conductors are separated by about 12 inches
as they go around the house, transients might behave differently on this kind
of wiring as compared to romex cable. But this explanation also seems like something
of a stretch to me, a grasping at straws, a bit far fetched!
I would like to know if this is something that any others have experienced. By the
way I have tried two different, brand new AFI breakers and both behaved exactly
the same - there is definitely something that they do not like about that circuit
or its wiring. Also by the way the breakers are QO type but have the green test
buttons and so are not affected by the recent recall of Square-D AFI breakers.
Baffled, but keeping crossed fingers crossed, in Portland, Oregon - Jim Howe
....
