Am about to replace hideous doorbell. AFAIK, I just have to unscrew tthe old one and attach the new one to the wires. BUT - how do I know which "breaker" as they used to call them, controls the doorbell? I looked in my switch box, where I have everything labeled, but did not see "doorbell". It rings in the kitchen. Anybody hazard a guess where it might be connected?
Hmmm, Typically door bell works off 24V AC, try to find the transformer feeding the door bell. Mine is mounted on the side of breaker panel box. Even if you don't turn it off, I doubt 24V AC will kill you if touched.
On 11/21/2009 11:51 AM Higgs Boson spake thus:
Still do.
Could be on any breaker; no official rule for where to put a doorbell.
Probably several ways to skin this cat. One would be to put a voltmeter on the transformer (that's the thing that supplies low voltage power--typically 16-24 volts--to the actual doorbell) and flip breakers until it goes to zero volts (assuming the transformer works). Probably the safest way; that secondary (low-voltage) side of the transformer isn't going to hurt you if you get shocked by it.
Friend told me that if I just touch one wire at a time, I won't get shocked. T/F? Makes sense ; circuit not completed; but hard to isolate wires in small space. How cope?
On 11/21/2009 12:19 PM Higgs Boson spake thus:
Welllll, that's true in *theory*. But probably lots of folks have been hurt (or even killed) when theoretically impossible.
Just to be clear, there are two issues here:
First issue: yes, in theory if you touch only the hot wire of a circuit, you won't get shocked. (Works for birds sitting on powerline wires, for instance). Problem is there are other sneaky way of the circuit completing itself, like through damp ground, your shoes and your feet. So the best policy is to never touch *any* wires (energized ones, that is).
Second issue: As I said, doorbells operate on low voltage (somewhere in the range of 12 to 24 volts AC). Getting shocked by such low voltages is a lot safer than high voltage (like the 120 volts in your household wiring). While it is theoretically possible to get electrocuted from even a low-voltage shock, it's unlikely. So it's safer messing around with low-voltage wiring that may be live than high-voltage wiring. Still not recommended (see best policy above).
I'd just wire it hot, since it is likely only 16v. But if that concept bothers you, you need to figure out where the transformer is. When I was a kid and we built houses the cave-man way, we always put the transformer near the service panel, to make future swapouts easy. In this place I am now, I found the damn thing in the attic, hung off the J-box that feeds the bathroom and hall ceiling light. Turn that breaker off, and doorbell is off.
When they make me benign dictator of the planet, I am going to require that GCs, electricians, plumbers, etc, map out whatever they do, and leave a legible rot-resistant diagram in a water-tight container screwed to the wall next to the service panel. Breaker maps, path of wiring and plumbing runs, location of any item with a lifespan less than the house itself.
-- aem sends....
I cannot recall the exact details, but I'm sure it had to do with moisture. Working on a 12V truck battery, I got "bit". Not sure what was touched by the tools or the wetness and leaning against the truck fender.
I was "shocked" it could happen. Hasn't happened since.
Didja ever try simultaneously touching both contacts of a little 9 volt "transistor radio" battery with your tongue?
Jeff
How else would I test them :-|/
You should try sticking a 98 volt battery to your forehead. There is a little sting to it but the most interesting part is the disruption to your vision. It's as though a movie camera shutter was being flicked open and closed at a rapid rate but slow enough to be perceived, very odd sensation. I didn't try it with the 525 volt batteries that were used by my Graflex Stroboflash IV with which I could strike quite an impressive electric arc. I miss that thing, I could melt retinas with it and it was fun at parties.
TDD
If you do the work in the daytime, you can switch off all of the individual circuit breakers and leave them off, and then switch off the main breaker. That will cut off the power to everything in the house, and you can do the work using daylight to see what you are doing (or use a flashlight, if needed). When turning the power back on, do the reverse -- switch the main breaker back on first while all of the individual breakers are off, then switch each of the individual breakers back on one at a time until they are all switched back on.
Or, you can do what others have suggested -- just do it while the power is still on. If you are nervous about doing that, just do it carefully, one wire at a time. You can even use pliers, wire cutters, and/or a screw driver that have insulated handles so your hands are not touching metal when doing the work. It's a low voltage circuit, so it should be no problem even if you do accidentally touch something. Plus, the doorbell switch itself is a switch that should keep any power from going to the actual bell unless the doorbell switch is pressed (assuming it is wired correctly).
Wouldn't worry about where it is connected...It's DC ...I've used a lot stronger DC voltage while being underwater...no worries...I'v replaced my doorbell hot outside in the rain... Hell i'd sit in my hot tub touching both wires at the same time.. Been a rig welder of thirty years welding with DC out on a pipeline in the rain... a doorbell??? sheesh...just wire it... Jim
Why would it be DC instead of AC? Hardwired doorbells usually have a step-down transformer that changes higher voltage AC to low voltage AC, but there is no rectifier that changes the AC to DC.
Yes, of course -- that is the "cowardly" way out. I just didn't want to go around resetting a houseful of clocks and appliances.
Will mull over all the good advice. I realize this to you-all is a trivial job, so I much appreciate the un-condescending attitudes of kind posters.
No Jay... to convert AC to DC would require a rectifier...to convert DC to AC requires a converter... Jim
On 11/21/2009 4:40 PM Jim spake thus:
touching both
Doorbells operate on AC, not DC.
And regarding the further conversation regarding conversion, etc., the only conversion going on is the stepping-down to low voltage AC by the transformer. (AC--> AC) No rectifiers used here.
On 11/21/2009 5:37 PM Jim spake thus:
That's true (the latter is usually called an inverter, but whatever), but the thing is that doorbells (99% of the ones found in houses) operate on AC, not DC.
I think that's what I said -- that there is no rectifier in the doorbell system to change the house AC to DC for the doorbell. So, the doorbell operates on AC, not DC.
You wrote that the OP shouldn't worry because "It's DC". I was just pointing out that it is not DC that is powering the doorbell.
a
Why not use common sense. Turn off half the breakers and see if the old doorbell still works. If it does not, then replace it and turn those breakers on. If the doorbell still works, turn those 1/2 breakers on and turn the other 1/2 off. That should stop the doorbell from working if it is on a breaker. Then replace the bell.
It is only 24 V at most on the secondary of the transformer if it is anywhere in the USA and will not kill you. The biggest problem is that if you get a shock you may make a sudden move and hurt your hand on something. But, to get a shock you have to have both wires energized, and that only happens when someone pushes the doorbell button, so keep eeryone who does not like you from pushing the doorbell pushbutton.
Mine was mounted up in the attic in a random spot. Spotted it when I was running wire one day.
Jon
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