We have a bedroom in attic that we seldom use. But with holiday houseguests
it is getting use. But, the electric baseboard heater is not working.
We have fuse panels. This particular room's heating is not identified, but
perhaps it shares a circuit with another heater? Anyway, I removed all fuses
and checked each one. No bad fuses.
The heater is controlled by a wall thermostat - It has white and black wires
coming to it - The thermostat breaks the white wire only, the black wire
really just passes through. I checked voltages - nothing across the white &
black on either side of the thermostat. But from either black or white to
ground (the box), I get 110v. Just is case, I changed out the thermostat for
a spare, but no change.
At heater, it is the same - no voltage between the incoming wires, but 110v
to ground from either side.
- If I see 110v to ground from black & white, why don't I see 220V across
- If I see the 110v to ground, does that mean that I do have power to the
Any suggestions as to how to further troubleshoot this problem?
This is what I would have thought, but the puzzle is that I get the 110v to
ground, but not 220v across the hot conductors. Changing thermostats made no
difference, so unlikely a thermostat problem.
Disconnect the power to the heater at the panel, and then disconnect the
wires at the heater. Then, reconnect the power to the circuit at the panel,
and turn the thermostat all the way up. Then, check, with your voltmeter,
across the two wires at the heater. Also, check each one to ground. The
one that shows 0 to ground is the one that is giving you the problem. If
the system was working before, it should work now, except maybe a fuse has
blown, or, when the remodel was taking place, the wire got cut somewhere
along the line.
OK, thanks for input - Problem is resolved!
Because heating circuits are not clearly labeled on fuse panel, I did not
know which one the problem heater was on. Today I pulled all heater fuses
(They are in double-fuse holders with hinged cover to prevent removal of
individual fuses). I now did not have 110v to ground at the wall
thermostat. We then plugged the fuseholders in one at a time until the 110v
re-appeared. So we found which circuit the heater was on..
I tested problem circuit fuses by using resistance meter across the brass
forks of the fuse holder and it showed continuity for both pairs. But, when
I removed the fuses, one was bad! This despite it showing no sign of having
blown - fuse strip was still intact - problem must have been internal.
Anyway, a new fuse solved problem - I guess next time I should remove each
fuse from holder, but still don't understand why testing across the "prongs"
showed no problem!
Existing main panel is Amalgamated Electric Cat No 200-4240 combination
service entrance/panel 200A with 19 double fuses and one large fuse pair for
range. There are two small sub panels with 6 breakers each that serve areas
that were re-wired at one time. There is another breaker panel in the garage
also fed from the main panel.
Would it be worthwhile considering upgrading main panel to a breaker panel?
Thanks for all the input guys!
Assuming the heater is 240 volt, it appears that either you do have one bad
fuse in the circuit, or the two feed wires were inadvertently wired to the
same leg in your panel. Find the origin of this circuit in the panel and
determine that you have 240 volts on the load side of the two fuses that
feed the circuit
Good Question! and the answer is YES it has always worked in the past, but
we had not checked it this winter until now.
This should answer most of the suggestions (I appreciate them!) - We have
lived here for 30+ years - The panel has not been modified during that time
nor the bedroom's wiring.
I understand how the voltages would be as measured if somehow both hots were
being fed from same phase - But at a loss to know how this could be.
We did have some bathroom rewiring done this past summer, but it should not
affect this area. But you never know!
Hard to believe it used to be connected to the right phase, and it
moved during the summer.
That is undoubtedly the reason. How, I have no idea.
You didn't answer my previous post. Is it permanent heating or space
heating? More importantly, do you know that it is 220, or might it be
If it were 110 and the heat is on, but the white is broken some place
between the thermostat and the fusebox, then you would get 110 at both
the whiite and black between ground, but 0 between white and black.
Although white is usually neutral and at ground potential, when the
white wire is broken, the 110 potential will flow from the black
through the appliance to the portion of white closer to the appliance.
It's all at the same voltage when there is no current flow.
Come to think of it, this would all be true with 220 also. In 220
only 110 comes from each conductor. Maybe the fuse or breaker, or
wire, for white or black, is blown, tripped, or broken. That would
account for your symptoms.
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