[tom34diy]

Someone told me something and I wonder if it is true. If I turn off the power to my central A/C unit at the circuit breaker, is there still a risk of shock if I do not also turn off the thermostat? I was told that if the thermostat turns on while I am working, it will send 12 volts to the unit where I am working, even if the breaker is off. True, not true? Thanks. Tom

 

[a\c don]

Not true.
Actually it's 24 volts.

 

[totaleclipse]

The thermostat does not produce voltage, it receives 24V on one wire, and depending on how the t-stat is set, sends it back to the unit on one or more wires. Now, with that being said, there are some units out there that have more than one power source, so it is possible to turn off one breaker and still not turn power off to the transformer that steps down the voltage that is fed to the t-stat.

Long story short, when in doubt call a pro to work on the unit. Saving a couple of hundred bucks by trying to do something yourself isnt worth the safety of you and your family!

 

[amickracing]

24v can pack a decent bite too... I was laying on some damp soil once and grabbed the 24v wires. Nothing life threatening by any means, but it sure got my attention.

 

[gregp]

safety

24v can pack a decent bite too... I was laying on some damp soil once and grabbed the 24v wires. Nothing life threatening by any means, but it sure got my attention.

The human heart works by electrical impulses produced in our body. Even the slightest jolt can cause serious injury or worse. Be safe, turn off ALL power to All system components. Use your meter, trust your meter.

 

[tjcsf07]

watch out for them run-caps too, they'll bite ya

 

[smokin68]

Someone told me something and I wonder if it is true. If I turn off the power to my central A/C unit at the circuit breaker, is there still a risk of shock if I do not also turn off the thermostat? I was told that if the thermostat turns on while I am working, it will send 12 volts to the unit where I am working, even if the breaker is off. True, not true? Thanks. Tom

You have to be very careful, as I recommend calling a pro if you have to ask this question, but I will tell you there may be multiple circuit breakers that need to be shut off to kill power to the unit. You might think it's off then BAM!!!!

 

[Mr Bill]

24v can pack a decent bite too... I was laying on some damp soil once and grabbed the 24v wires. Nothing life threatening by any means, but it sure got my attention.

Been there done that it felt like 120 volts didn't it.

 

[tinknocker service tech]

its 24 volts and about 40va witch can be enough to kill you if the conditions are right

the answer is yes

leave the unit to the pro

 

[luskys a/c]

Please Mr. DIY, if your systems needs something more than cleaning the coil then call your HVAC technician. Find a technician you can trust to handle any questions and problems you have. He or she will take care of ya!

 

[seatonheating]

I do believe this guy has been warned before about DIY help. This thread should be closed!

 

[tom34diy]

Yes, I was warned about seeking DIY help, but that is not what I had in mind so you do not need to close the thread. I was just asking a question and this seemed like a good place to find the answer. And, BTW, I have found a serviceman I believe I can trust to do the work I need to have done, based in part on what I have learned from this forum. This forum may just be for experts in the field, but the information helps us customers be informed so we do not get taken for a ride. Thanks for the replies to my question. Tom

 

[seatonheating]

Yes, I was warned about seeking DIY help, but that is not what I had in mind so you do not need to close the thread. I was just asking a question and this seemed like a good place to find the answer. And, BTW, I have found a serviceman I believe I can trust to do the work I need to have done, based in part on what I have learned from this forum. This forum may just be for experts in the field, but the information helps us customers be informed so we do not get taken for a ride. Thanks for the replies to my question. Tom

If you are hiring a pro like you said, then this information would be meaningless to you.

 

[bltinnc]

ok what kills ya volts or current

 

[RoBoTeq]

ok what kills ya volts or current

Amps.

Just let a 24v wire find its way under your fingernail and see if it'll hurt ya!

Also, don't trust disconnects. In line with the capacitor mention, I had an incident where I pulled the disconnect to test the compressor for an open winding. While pulling the wires off of the compressor to test its terminals, I got stung pretty good (bad?) by the wire connected to the capacitor. Thinking the capacitor had held a charge and that I had just discharged it, I grabbed the wire to secure it out of my way. That's when I was pinned against the wall. Turned out the electrician bypassed the pullout on the disconnect.

 

[bltinnc]

car batteries are 200 amps and they wont hurt you?

 

[smokin68]

car batteries are 200 amps and they wont hurt you?

D/C much safer than A/C, but still can hurt you.

 

[beenthere]

car batteries are 200 amps and they wont hurt you?

The voltage is low enough that it won't go through as easily.

If you were wet, it will be another story.


Like mrbillpro said, when your wet and get hit by 24volts, it feels like 120.