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Identifying voltagesUpdated 8 months ago

Warning! High Voltage!!
Any work with high voltage equipment can be dangerous or even fatal if you do not take proper precautions. You should never work with live wires.


Identifying Wires by Voltage

You can determine which cable is coming from the circuit breaker panel and which cables go to the heater by using a voltmeter. Reference the tables below to determine the identification voltages.


240V installations

L1 to L2 - 240V

 Gang Box Wires

            Identification Voltages 

Second supply wire (L2) (240V) 

Ground to L2 (120V)

Supply Wire (L1) 

Ground to L1 (120V)

Load Wire 

Ground to Load (0V)

Group/Copper 

N/A 


120V Installations

L1 to N - 120V

Gang Box Wires

Identification Voltages 

Neutral Wire

Ground to N (0V)

Supply Wire (L1)

Ground to L1 (120V)

Load Wire

Ground to Load (0V)

Group/Copper

N/A 


120V or 240V System?

There are two quick and straightforward methods to identify the voltage your heating system operates on. It's important to note that these methods are general guidelines and are applicable to most homes. However, some homes may have unique setups, and these guidelines may not be universally applicable.

Method One

Identify the breaker in your electrical panel connected to your thermostat. If you observe a single breaker switch resembling the one depicted in the image below, it is indicative of a 120V setup



If you observe a double breaker, as depicted in the image below, it is indicative of a 240V configuration.




Method 2

If you have a Single Pole breaker -  it's indicative of a 120V configuration. 

If you have a Double Pole breaker - it's indicative of a 240V


If you are unsure of any of these, Please consult with an electrician! OR Book an installation appointment with a Mysa Pro


For any inquiries or support, reach out to our dedicated all-human Customer Experience team.

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