We have a wall switch -- actually three switches -- thatcovers our
combination bathroom light, fan, and heater (and all-in-one ceiling unit).
The switches to the light and fan work fine, but with the heater, we would
occassionally notice a spark when we used the switch to the heater. Then the
heater quit working. When I took out the old switch, it was fried where the
heater wires connected, so I put in a new switch.
Now, we occassionally get a spark at the wall switch if the heater is turned
on and off right away. The spark occurs only when we push the off button.
Doesn't happen every time, just when it's turned on and off quickly -- as
happens on occassion when someone accidentally turns on the heater when they
meant to turn on the fan or the light.
Is this spark anything to worry about, and if so, what can I do to fix it?
This was the only one-piece 3-switch wall unit I could find, and it's
supposed to be made specifically for these 3-in-one bathroom
Your advice would be appreciated!!
The spark you see is because of an induction coil in the line which
happens to be the motor winding. I've noticed that all these have this
little spark. Is is good for the switch---no. Can it be stopped, yes.
To do that you will need to install a capacitor across the switch. A
.1uF at the proper voltage rating should do but you might want to take
your new switch to an electrician to install that capacitor. The cost
for the capacitor is less than 50 cents. BTW, the spark will not damage
yes, start worrying.
who: you and an electrician
what: check the amperage of the heater and the switch to see if switch
is sufficient amps. check the circuit breaker size and wire size and
see what other devices may be sharing the same circuit.
where: at the heater electrical plate, at the switch rating label, at
the electrical panel.
why: to avoid overheating of electrical items and avoid repeating the
burnout of a heater if it was caused by underrated switch or overloaded
circuit or insufficient wiring size.
visible sparking is not normal.
It has two buttons, huh. Is this like the switches they made 50 years
REgardelss, I haven't seen what Joey describes. Maybe he is right on.
But just because the first switch was damaged at the screws (did you
make the screws tight enough when you installed it, btw?) this one
might have a different problem.
Is this a silent, barely detent switch? I don't know how they work,
compared to the noisy clearly-detent swtiches that I've taken apart,
but when the lights are off I've seen sparks inside both kinds of
switches, and afaik, that's ok.
Insidethe plastic case. If the sparks are on the outside, that's bad,
but how would you see them if you don't see them through the handle or
button? And that would mean they are inside, which is ok, afaik.
In other words, when you were aiming for the light switch but hit the
heater instead. So it is dark in the room, and even lighter loads than
a heater will often make a spark that is visible in the dark through
white or cream colored parts. (If you have a brown switch, you won't
But you've already replaced one of the switches. Was it a special
replacement switch, or did you use an everywhere available one??
If special, I can hardly believe it's not rated for the heater, but
anything can happen. You can check the rating on the stitch. It is
often embossed in the metal plate that screws to the box and holds the
actual switch, so you only have to take off the cover.
I fix laminating machines for a living. They have similiar current draw
to a heater since basically they are a 1500 watt load. they have a
built in switch that can be seen sparking internally in a dark room. If
I plug one in and use my wall switch it sparks too from the load.
if the swich is working and not hot to touch I would forget about it.
Absolutely correct, the heaters are 1500 watt and the units often come with
rather cheesy triplex switches, for light-heat-vent, and of course the heat
switch with the heavy load will arc and burn out sooner than the others
Thanks everyone for the advice.
Now I'm really confused :-) Many are saying "don't worry about it unless the
switch gets hot from the spark" (it doesn't get hot, and doesn't spark at
all unless I swith it on and off fast) and others are saying "call an
electrician immediately, it's not normal and the switch might be
Is there anyone else out there -- especially electricians -- who care to
weigh in on the matter?
I don't think it is the spark you see that might make it hot. It is a
bad connection inside the switch. Greater than average sparking could
be a symptom of that. But the spark you see only take a tenth of a
second. Not enough time to make much heat in a functioning circuit.
But, when the switch is closed (ON), when the two contact points of
the switch are resting against one another, if the connection is
still** bad, it will generate heat for the entire time you are using
the heater. That's when, after a while, you will be able to feel some
heat, and you shouldn't feel any. There shouldn't be any heat
generated when the switch is resting closed. (Well, maybe a
"microscopic" amount, but nothing close to what your senses should be
able to detect.)
**There is always a bad connection^^ for a fraction of a second when
turning a mechanical*** switch on or off. It's the small period of
time when the two contacts of the switch are not actually touching,
but are still close enough that current can jump across the space in
between. You can look at some very high quality relays, for example,
and see tiny sparking between the contacts.
^^It's a bad connection because it is not fully open-- there is some
current flowing; but it is not a good connection -- the resistance is
substantially greater than zero.
***As opposed to a transistor switch, like an SCR (selenium controlled
rectifier, iirc), which I'm not trying to discuss.
No, it sparks every time^^^. You don't see it when it's not dark in
^^^Every time you turn it off, or on, or both. I'm not sure which.
Except once in a while it might not. :) but it is not because you flip
the switch twice quickly in succession. For you it is quick. For the
electricity, they are two separate events, one not affecting the
Some posters may have thought the sparking was not coming from inside
the switch. You didn't say explicitly. Others might have a different
image of how big the sparks are. Those who say no problem think the
sparks are short because they are contained in a small place (the
inside of the swtich) and only the light they cast is rather great.
At least it seems that way in the dark.
Other posters might agree with me about what is happening and might
still think it is dangerous. I don't know why.
I'm not an electrician, but I've used electric switches since I was 2.
Switch contacts always arc, every time they open. The amount of arc depends
on the load... a motor or heavy appliance will cause more than a light bulb.
Whether or not you see it depends on the construction of the switch and the
amount of light in the room. If there is a gap around the operating lever,
you may very well see more than if there isn't.
Having said that, however, if the switch is old it may be arcing more due to
worn contacts. If the switch is new, it is probably OK. Only someone
looking at it can tell you for sure.The only way to know is to have an
electrician check it out, or change the switch.
Apparently the switch you are talking about is one
that comes with the ceiling unit and you replaced
it with a similar set of switches.
I'm not an electrician but I can use my brain and
have no trouble installing or repairing normal
house wiring. Anytime you can see a switch spark
there is something wrong and you need to replace
it. Ask yourself these questions, Do you have any
other wall switch that sparks? If you have an
electric stove, do you see sparks when you turn on
or turn off a burner? Do you have motors that you
turn on and off and you see sparks at the switch?
The answers should be no, and your brain should
note that a spark at a switch is unusual and means
Either your heater element draws too much current
for the switch, or the switch is of extremely poor
quality or the connections are poor.
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