I have problem at home. Recently my oven, water heater, dryer....
stopped working. I tried playing with the breakers but it all seems
to be fine. One curious thing in the panel is that if I measure the
voltage between the 2 hot wires it reads 58volts... if I measure each
of the hot wires to the ground it measures 110volts.. is this normal?
Should the voltage between the 2 hotwires measure 220V ?
Since you are getting 110 (should be 120 in most areas) I doubt if it is
the power company. I suspect you have a floating neutral and that needs to
be addressed as you cold end up with damaged electronics or even a fire. (I
had a boss once that burned down his photo studio due to one.)
However since I am not sure of exactly what you are measuring and how, I
would suggest asking the power company to come out and make sure their end
is OK first.
Note: If you have or can find an old analog volt meter rather than that
digital, I suspect you will find that those 54 V measurements will become
0V. In fact if you go now and measure them again you might get something
lower or higher this time. If so that is another indication of a floating
If he's measuring between the "two hot wires" he should read 240 volts
regardless if his neutral is intact or not. The only reason he would get
anything less would be one dead hot leg. When he reads between each hot leg
to ground, he reads the good leg normally and the dead leg he gets a
backfeed reading through any 240 volt appliance that happens to be turned
on. Both will give a 120 volt reading.
If it is truly an open hot leg then surely somewhere else in the house
there should be signs of some of the lights not working and some of the
outlets being dead. That is just the way the standard North American
split 240V system works. I won't pretend to know what it is that the OP
is actually measuring or how he is measuring it -- there are just too
many variables involved especially if he is using a DVM.
Personally, I would start measuring at the utility feed and then through
the bus bars and forward but there is no way I will encourage a
non-experienced person to do what I would do. I learned to do much of
this while I was still a teenager and credit my continued breathing to
an abundance of caution.
Actually, I got to thinking about what I wrote and started to wonder if
it is possible to get cross-feeding from one bus through some 240V
device into the other bus without enough odd behavior elsewhere in the
house to notice. I guess it is possible if one wasn't looking for the
symptoms. Probably the best thing to do would be to simply turn off all
of the 240V breakers in the panel to eliminate any potential
cross-feeding. If it was one dead bus then surely some of the lights and
outlets would go dead with all of these breakers turned off.
Has anyone ever seen a half-tripped service main breaker? I haven't, but
I've seen it in a few regular 240V ganged breakers and know that they
can cause some odd things to happen. It might be worthwhile to simply
turn off the main and then turn it back on.
That's exactly why he's getting a 120 volt reading from the dead leg to
ground. Lights will work on the dead leg through backfeeds through 240 volt
appliances and Edison circuits, (circuits that share a common neutral) but
they won't be full brightness
Not necessarily. If one leg's connection to the utility is broken,
he could see no 240V devices work, and _all_ of the 120V stuff appear
to work. If a 240V device (like the water heater) is switched on, it'll
backfeed one 120V side into the other.
Ordinarily, you'd expect the lights on the "broken connection side"
to be dim, but if you don't load it up very much, and the 240V device
is large enough (water heater, stove, dryer), the lights may well not
dim noticably at all.
The voltage difference between the two legs at the panel is the
voltage drop across the 240V device.
Simple way to check this stuff out without opening anything up:
1) Cycle the main breaker, and see if things work any better.
2) Turn off _every_ 240V breaker, and see if he loses one half
of the 120V circuits.
Age and Treachery will Triumph over Youth and Skill
Your 120V circuits will each be on one side or the other of the 240V.
Assuming you are able to tell which is which, if you turn off all the
breakers for circuits on one side as well as any 2-pole 240V breakers, what
happens to power on the circuits on the side that remains on?
If the neutral is open then these should be dead as well. But for that to
happen you'd also have to have also a missing or bad ground at the panel or
maybe your ground is ok but the utility's grounding of the neutral on the
secondary side of the transformer could be bad.
However, with a neutral open but a ground that is present but mediocre you
might read proper voltage with nothing turned on and even have satisfactory
operation of a few lights and other small stuff but severe voltage drop
when trying to drive a heavy load.
As the others have said call the utility or a professional electrician ASAP
and be VERY careful about coming into contact with ANYTHING including what
ought to be grounded. If the neutral is open somewhere and grounding
broken or insufficient not only can the neutrals be lethally hot but it's
even possible for the grounds to be hot (less likely with conduits although
possible depending on physical construction but easily possible if the
grounds are just wires within Romex and the like).
I had a neighborhood transformer fail once, with wierd readings and
one side of transformer fried, still produced a wierd low
real bear to figure out....
call power company, as first step
I didn't mean "side" in the literal sense of how the panel is laid out.
We've got one where it's the top group vs. the middle group with mains at
the bottom and 240's that straddle top and middle.
Anyway, looks like he's got one hot side open.
Wow I wasn't expecting these many answers, Thanks ALL!!
The way I measured the hot wires is I turned off the main breaker and
used a digital volt meter, it gives me around 50-58 volts between the
hot wires but each of them gives 110V when I measure against the
I am having problems with some devices and some lights only turn on
100% if I turn on the oven.
its best to not use a digital volt meter when doing home repairs, they
are way too sensitive..........
cheap analog meters are fine, or put a trouble light 50 watt load on
the circuit then check with a digital meter.
a 25 watt light bulb is enough of a load to also let you know whats
up, just connect across connection and see if bulb glows
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