It sounds like you lost one leg of each cable, but I can't imagine how that
could have happened. At this point you'd need to disconnect each cable from
the breaker and at the load end, and do a continuity test to verify each
Even if he cut 99 percent through a wire, you'd still get a full voltage
reading . The dryer or airconditioner wouldn't work, but the no load reading
would indicate full voltage. The most puzzling thing is that its affecting
two independent cables and breakers. In the real world, that just doesn't
happen. let us know what you find. Good luck
Have you measured the voltage at the output of the breakers, in the
breaker box, when the AC and dryer are attempting to run?
Are the bad voltages you've given us at the receptacles? Or somewhere
else nearby? And are they when the AC and dryer are attempting to
run, or when they are OFF?
They may be, but it bothers me that you keep saying they are both
wroking perfectly. AFAICT, all you have done is measure the voltage at
the output end of the breakers. There is more to working perfectly
than that. Like, Do they both trip at right current?
Not that any other problem would necessarily be related to the problem
you're posting about, and not that I can help you much with it, but on
principle and practice it bothers me that you keep saying they are
working *perfectly*. It also makes me think you are vulnerable to
I'm betting L2 is open somewhere along its path and you're using an
electronic voltmeter which is responding to a current being capacitively
coupled from L1 to L2 and displaying that current as "11 volts between
L2 to neutral".
Similarly, the L1 to L2 reading is low because of the open on L2 and the
voltmeter is being "measured" through the high impedance of the
capacitive coupling between L2 and neutral.
If it was me seeing that 11 volts between L2 and neutral, I'd stick the
fingers of one hand across the voltmeter probes and watch that voltage
drop to zero. But I won't advise you to do that because some nervous
Nellie on this group would scream you could get "burned" is the open on
L2 magically reconnected at just that point in time. <G>
Having recently celebrated my 50th college reunion, I remembered the
Brit Professor who taught our sophmore course in "Rotating Electrical
Machinery". We were mucking around with motors and generators and 3
phase power in the lab when he said, "You men will never become real
engineers until you learn how to "take" a shock. <G>
Assuming the voltages were measured with an electronic VOM I'd say that L2
is open between the breaker panel and the load. Most likely your
electrician cut or drilled through it.
Note that a 220/240V load doesn't care about the neutral; it only cares
keep in mind the OP says he has two double pole 40 amp breakers and two
cables, one to the dryer and one to the A/C unit. Both cables show the same
low voltage at the load ends. He also says a continuity test shows all
conductors are continuous
Firstly, thanks to all responders.
The problem was caused by the contractor who installed the line for the new
addition. He did, in fact, slice cleanly through the two 240V lines that
were behind the wall into which he drilled the hole.
The 11V, I was told by an electrician, actually means zero, since just about
anything, including one's own skin, has that much electricity in it. So,
despite the fact that I said continuity was tested, that was before I
understood that 11V could mean zero.
The original contractor came in and repaired it, firstly by cutting a hole
in the ceiling in the basement so he could see and confirm the damage, and
then by going upstairs into the kitchen, cutting a hole in the wale above
the problem and putting in a box in which the old lines were (presumably
correctly) spliced onto a new leads to go to the breaker box.
We have A/C and a dryer again, for which my bride is extremely grateful.
Not only that, you didn't understand what it means to check
continuity, and maybe you still don't. You don't check continuity by
finding 120 volts at one end and 11 at the other. Or even by finding
120 at both ends. You check continuity by disconnecting the hot end,
the end at the breaker, and disconnecting the dryer etc. at the other
end, and measuring the resistance, the ohms, from one end of the wire
in question to the other.
You coudl do this either by connecting two wires in the same cable at
one, and measuring the resistance between the two of them at the other
end. It should be zero or substantially less than an ohm. OR By
running your own wire from your owhmmeter to the far end of the wire,
and the other wire/test lead from your ohmmeter to the near end of the
wire, and measuring the resistance. It should also be zero or at
least substantially less than an ohm. If you use a continuity tester,
you can find continuity if the buzzer buzzes or the light glows.
You should never have told us you tested for continuity. Especially
since that statement confused people. All you did is test for
voltage, and you should have told us the details of that, but not used
the word continuity.
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