Our neighbor's house was recently hit by lightning. All that we
suffered were blown GFCI's throughout our house. After replacing the
GFCIs, all outlets are measuring 123 volts as normal except for one.
The outdoor outlet is measuring 97 volts and will not power anything.
Any clue what's wrong here?
You probably have a fried wire somewhere in either the hot or the
neutral side of the line feeding the outlet. First, disconnect both
the hot and neutral wires at the house end, then tie them together at
the outdoor outlet and measure the resistance at the house end.
Should be less than 1 ohm if the wires are ok.
On Thu, 11 Mar 2010 20:34:01 -0800 (PST), "hr(bob) email@example.com"
Even though he thinks he has disconected both wires at the house end,
lots of things could go wrong doing that, like disconnecting the wrong
wires. He should first measure the voltage between the two wires
before tying them together. If the wires really are disconnected, the
voltage will be zero, even with an analog meter. At least it will be
a lot lower than 97.
He's asking because digital meters have such high resistance that they
will read odd voltages picked up as "crosstalk" from other nearby
wires. If you are using a digital meter you need to have a load on
the circuit like a lamp.
If the outdoor receptacle is a GFCI type, the power to it is likely coming
from the nearest outlet, on the inside of the house. Check to see that the
connections are good on that outlet, and any other nearby outlets
Let's do this by the numbers:
1. If the outlet doesn't measure 115-125 then the actual reading is zero
irrespective of what the meter says.
2. When the actual reading is zero, you have a broken connection.
3. This broken connection is either at the outlet itself or upstream.
Ive been hit by lightning, if you suffered Gfis blowing you suffered
alot more but it may not be evident yet and you didnt check
everything. Things will start failing over the next year or less, its
time to check everything electronic and think about that policy you
have that covers lightning damage.
It's not whether it's a digital or analog meter: It's what the input
impedance of the meter is. My old Triplette with a mirrored scale will read
nearly the same voltage as my Fluke on similar scales because they have
similar input impedances on those ranges. A light bulb, any resistance
across the wires will kill the voltage if it's just a phantom voltage. In
fact, so will a 47k, 100k resistor and even higher, depending on the
situation. I use 47k; high enough to kill the voltage but not low enough to
quickly burn, even snap, if it's a real voltage for some odd reason. Phantom
voltages cannot light a light bulb's filament either; so if it glows, there
is a real voltage there.
Newsgroups are great places to get assistance.
But always verify important information with
Good, correct information. However in general the dividing
line is between digital and analog.
Afer reading your reply, I realize that it is possible, if
someone assumed my comments were 100% right, could get themselves in a
dangerous situation. I stongly suggest that no one assume the
independance base on the type of display.
Please anyone who is not sure about all this, be very careful.
If you are not sure, you liekly should not be using the meter.
BTW I once worked for a man who thought he knew what he was
talking about and burned down his own business, because he did not
understand what happens with a floating neutral. Lucky no one was
My guess is you are using a digital meter. They have a very
high interal resistance that means they can measure false high
voltage. Do you have access to an old analog meter. They blead off
induced current. You can do the same thing by putting a small load on
that circuit, like a 120V test lamp. Chances are it will not light
that test lamp or move the analog meter.
Assuming the above is correct, then you have a connection
problem (open circuit) somewhere between where you are measuring and
the power source.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.