My house has a multi-branch circuit on it. This circuit supplies power
to a few bedrooms and a bathroom. The two breakers that supply power
to the circuit are 20amp each.
At 7pm tonight I turned on a few things in one bedroom. This bedroom
has two duplex outlets. Everything I turned on worked. At 7:15pm the
entire room had no power. Neither the outlet I was using at 7pm had
power nor did the room's other outlet.
I checked the two breakers that supply the circuit; neither had
tripped. There are no gfi outlets involved. In the panel I checked
the hot and neutral wires for the circuit; all are tightly attached.
All of the other bedrooms in the house had power at 7:15pm with no
What on earth could cause this? How would I troubleshoot this problem?
Sounds like you have an open neutral. Use a test light and see if you get
120 volts between the "hot" slot of the outlet and the ground. Most likely
the neutral wire has come loose in an adjacent outlet. Try plugging a lamp
into a "dead" outlet,(make sure its in the on position) and bang on each
adjacent outlet to see if the vibration at any outlets causes the light to
come on or flicker. If it does, open that outlet and check the connections,
especially back stabbed connections
I just found another outlet, in a bedroom next to the one that
originally caused a problem, that is dead.
In all of the dead outlets I have no voltage between hot and neutral
and no voltage between hot and ground.
I just putlled out the first dead outlet that I found, and it looks
fine. All of the connections are tight. When I touched my tester on
the hot and neutral screws and on the hot and ground screws, there was
This seems bizarre to me. Everything worked fine a few hours ago and
has been working fine since I bought the house three years ago.
OK, it's not an open neutral, it's the hot leg that's open. It doesn't sound
like an entire circuit, so again you're looking for a bad connection, but on
the hot leg. I would check all live outlets that are near the dead outlets.
You want to find an outlet with power coming in, but the hot leg of the
downstream wiring is loose
I just checked the two breakers that supply the multi-branch circuit,
and there is voltage between both hot screws and a neutral. No obvious
problems at the panel.
I will start on the live outlets close to the dead ones and see what I
Thanks very much for your help.
Turn off the breaker that you know supplies the "multi-branch circuit"
and then look for outlets/lights that worked before but are now NOT
working. Then open each of those checking for bad connections of any
kind. This may identify the point of a bad connection. You may find an
outlet with wires pushed in holes, or wire nuts which have become flaky.
I would also be suspicious of the new box and work done at that time,
since it was only three months ago. Perhaps did the worker create some
sort of extension on the wire feeding your bad circuit? Maybe his/her
work has a problem. --Phil
Phil Munro Dept of Electrical & Computer Engin
mailto: firstname.lastname@example.org Youngstown State University
Could be a number of things. As RBM suggested a bad neutral connection is
one possibility. I would open up the electrical panel to see if there was
juice coming off of each circuit breaker. If not then you might have lost
one phase and need to determine if it is before the electric meter or after.
I would pull the electric meter to find out.
Other things I would check:
Connections on the main breaker.
All neutral, ground and hot connections in the main panel.
Open up a few outlets at the beginning of each circuit and check for a hot
and a neutral. I would run a wire to a water pipe and check the hot to the
water pipe. If you have juice, then the neutral is missing.
Open up a few junction boxes and check for loose connections.
How old is your house?
How do I do this? Touch the tester to the hot screw on a breaker and
to the wire that grounds the panel to the buried rods outside the
What do you mean, check for a hot and neutral? Do you mean, place
tester probes on hot and neutral screws?
Regarding a water pipe: if I understand you correctly, the idea is that
my pipes are grounded (they are connected to the main ground wide in
the house which goes to two buried rods). If I have voltage in a box
between hot and water pipe, then I know that the neutral is missing in
the box. Is this right?
So far all the outlets I have checked are either fine or have no
voltage between hot and neutral and between hot and ground.
Age of house: about 40 years. 200amp upgrade was done about three
months ago. The multi- branch circuit now causing problems is only one
of two original circuits left in the house (the other is a dedicated
boiler circuit). There a no other known electrical problems in the
house (all other circuits work, no flickering, no popping breakers,
You said that you already checked for juice between the breaker and the
neutral at the panel. That is sufficient to tell you that you have juice
coming from the breaker.
You will have to start opening up outlets and junction boxes in search of a
loose or broken connection. Start with the outlets close to the electrical
panel. The problem could be in an outlet that is still working. Try
shutting off the circuit breaker to see what else is on that circuit and go
What you have is some sort of electrical failure. It's not a big
deal, and it may or may not fix itself. Just dont use those rooms at
night for awhile or use a flashlight. I'm curious how you knew it was
7:15. Didn't the clock go out along with the power?
On 13 Oct 2005 17:13:58 -0700, email@example.com wrote:
Somehow I suspect there is a GFI involved. Do you have any anywhere in
the house? This circuit you are talking about includes a bath and should
have one added if it does not yet. Often GFIs show up in odd spots.
You're not in Vancouver, are you? It sounds just like an old house where
I rented a suite until it was sold (ominous music...) 3 years ago.
Like you, one circuit, occasional flicker, sometimes nothing for months.
Then *blink*, dead circuit, could be 5 minutes or 5 hours, no telling,
then *blink* back on again.
Check your GFIs. Many circuits can be subject to nuisance tripping.
As a previous poster said, GFI's can be in oddball locations, away
from the main circuits they control. There are two in my house...
One in the garage and one in the kitchen. These are the outlets that
have a "Reset" and a "Test button".
Very often, what's done is to wire the power to socket 1, then 2, th en 3,
and down the line. If the wire that comes off the back of socket 1 (going
from 1 to 2) is bad, then you lose power in sockets 2, 3, 4, etc.
The solution is to turn off the breaker. And then go around and find which
socket went dead that was live before. Pull it out, and make sure the wires
are under the screws on the side, not the "stab in" things on the back.
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