The short answer is no, it’s not OK – you increased your risk of electrocution and that’s never a good thing specially for a DIYer. Now that being said, everything is working and you didn’t burn down your house, so you got off OK, but generally speaking, this was a bad idea.

Should I turn off power when changing thermostat?

Virtually all room thermostats operate on low voltage that carries little risk of harmful electric shock. However, it is always wise to shut off power to a thermostat at the service panel before examining or working on it.

Do I need to turn off the power to install Nest thermostat?





You should always turn off the power before you connect or disconnect any wires from your Google Nest thermostat, and you should test to make sure that the power is off. This helps protect you and your equipment during installation or troubleshooting.

What do I turn off when installing thermostat?

You just put off the circuit breaker marked “HVAC,” “Cooling” or “Heating.” All power to the HVAC system will be cut. This means the power of the thermostat will also be turned off automatically.

Do thermostat wires have power?

While some people think the C wire is what powers the thermostat, this isn’t entirely true. Typically, the “hot” wires, or the wires that provide power to the unit, are the heating and cooling wires, labeled Rc and Rh respectively. They provide the source of 24V power that comes into the main HVAC control board itself.

How do I turn off the power to my HVAC?

Quote from the video:
Quote from Youtube video: The power switch will look like a regular light switch and once it is located you should switch it to the off position.

How do I turn off my main power supply?





Quote from the video:
Quote from Youtube video: So make sure you bring a flashlight with you find the main breaker inside the panel and switch it to off you should hear a click which.

What happens if you wire thermostat wrong?

Potential consequences of improper installation could include: Electric shock. Blowing a circuit breaker. Damaging the thermostat unit, the electrical system or even the AC/furnace unit itself.

Does thermostat need electricity?

Most thermostats that control central heating equipment, including furnaces, boilers, and heat pumps, are low-voltage thermostats that typically use 24 volts of electricity. Electric baseboard heaters and in-wall heaters may use line-voltage thermostats that use 120 or 240 volts of electricity.

Do all thermostats require power?

Most digital or WiFi thermostats require power to operate. Power: Provides power from the transformer on the furnace or boiler. Power for Cooling: Provides power for the cooling cycle. If the heating and cooling systems share a transformer then a jumper may be connected between the Rh and Rc terminals.

Where does a home thermostat get its power from?



voltage transformer

Most room thermostats on heating and cooling systems receive their 24V AC electrical power from a low voltage transformer that itself is usually found at the boiler or furnace (blue arrow in our photo at left).

How do I know if my thermostat has power?

Quote from the video:
Quote from Youtube video: Check this by going from our red to our green our green is going to be our blower motor. So you can see here I have twenty six point nine volts. The voltage can read anywhere from 24 to 28 volts.

Do you need a C wire for thermostat?



While your thermostat may not technically need a C-wire to operate, it gets the power for its screen and Wi-Fi capabilities through “phantom power” or “power stealing.” Basically, this means your thermostat gets a kick of extra power whenever your HVAC system is running.

How do you wire a new thermostat?

Quote from the video:
Quote from Youtube video: Sheetrock. If the hole was directly above you may already see the chain you can use this if you need to in this case we're just going to grab it and pull it right through.

What color is C-wire for thermostat?

Blue wires

Blue wires are also called “C” wires because they are the Common wire. C wires are necessary for any “smart” thermostat that needs to be connected to a power source 24/7, regardless of your heat pump type.

How do I bypass the C-wire on my thermostat?



Quote from the video:
Quote from Youtube video: Connect the extra wire to the C terminal of Union thermostat trace the extra unused wire from the thermostat to the furnace board make sure it's connected to the C.

What does C wire do in thermostat?

A C-wire, or a common wire, runs from your low voltage heating system (24v) and carries continuous power to your thermostat. In today’s electric market, most newer heating and cooling systems have C-wires, which guarantees compatibility for the installation of all smart thermostats.

Where does C wire go on thermostat?

If your system has a C-wire, it might be in use or just tucked away behind your current thermostat. If your system doesn’t have a C-wire, you’ll need to run a new cable from your furnace to your thermostat to install most of the modern smart thermostat models.