HELP: wall switch sparks when turned off

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 fan/light/heater units.
Your advice would be appreciated!!
--
DK



Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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 the motor.
J
DK wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
It's really not. All switches spark internally when they make and break connections. The heavier the load, the larger the spark.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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. when: asap 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. faq at: http://www.landfield.com/faqs/electrical-wiring/part1 /
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
its probably nothing to worry about.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It has two buttons, huh. Is this like the switches they made 50 years ago?
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 see anything.)

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.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
DK wrote:

I'd feel the switch plate for warmth. If it is maybe the contacts are pitted too much. I'd just replace it. There is such a thing as spark proof ones(used in hospitals or in the mine; better made).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Great idea.

I think they still make sparks like others, but the whole area (volume?) is enveloped in some sort of oil so the spark can't ignite anything.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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 overloaded."
Is there anyone else out there -- especially electricians -- who care to weigh in on the matter?
--
DK



Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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 the room.
^^^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 other.

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
mm wrote:

Tall kid.
R
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Probably not - both of my 2 year olds were expert wall switch manipulators. Amazing how high they can jump at that age. ;-)
- Rich
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Ben Miller
--
Benjamin D. Miller, PE
B. MILLER ENGINEERING
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
DK wrote:

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 trouble.
Either your heater element draws too much current for the switch, or the switch is of extremely poor quality or the connections are poor.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
other similar 4,550 postings for you to read at: http://groups.google.com/groups/search?hl=en&q=wall+switch+sparks+&qt_s=Search
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    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.