220 House Breaker Box Mystery

[Robobrainiac]

I am curious if anyone on here might be able to help identify some breakers I can't figure out what they do. We have lived in this house for 5 years and I have tried to identify all the circuits. Whoever labeled my box was a toddler. I have 7 220 breakers. I have 2 that I am not sure what they are.

I have identified
Well Pump
Oven
HVAC
Water Heater
Dryer


The two breakers I have not figured out yet is one looks labeled

M C

the other says

Well Farm Pump

and is black sharpy crossed out.

Does the HVAC use two 220 breakers? I "think" if I squint hard enough the M C might say A C. I know the breaker I identified as HVAC is labeled furnace. If I turn off "furnace" the thermostat turns off and the vent blower stops working. This happens whether or not I am using heat or air conditioning. I do not notice any change when I turn of "M C".

The sharpied breaker is a complete mystery to me. When it is cold outside that breaker can be warm to the touch. As if it is doing something. When our water has frozen I have found that breaker tripped maybe 2-3 times in the five years we have lived here. I have buildings on the property. I have a pole barn that has its own breaker box. I have a garage that is sub paneled off the pole barn. I have a cabin that has its own breaker box. I have a RV plug in area that has its own breaker from the pole barn. The sharpied circuit does not alter power to any of those budlings when switched to off.

I will include a picture of the label.

Thank you for your time and I look forward to hearing your responses.




EDIT:

I was able to verify "M C" labeled 15/13 controls the exterior HVAC air conditioning system. I am still not sure what the sharpied breaker does.

 

[Admin]

 

[dweber23tr]

MC to me looks like a sloppy A/C which normally would be 220. If you turn it off and then turn your AC on, the condenser outside should not be running.

 

[Robobrainiac]

MC to me looks like a sloppy A/C which normally would be 220. If you turn it off and then turn your AC on, the condenser outside should not be running.

Does that mean the "heat" portion has its own breaker then?

 

[Fatsquatch]

Does that mean the "heat" portion has its own breaker then?

Likely.

 

[Robobrainiac]

Just for clarification purpose

13/15 is what I think is M C

4/2 is the current mystery

 

[trigger]

There should be a fuse/disconnect outside for the AC as well, that might have the amperage on it? But yes, the furnace and the AC are entirely different units electrically.

 

[WagginTail]

Does that mean the "heat" portion has its own breaker then?

Yes. Your MC looks like A/C to me

 

[Jankyeye]

You could take the panel cover off and see if there are any wires attached to the mystery breaker.

 

[Dirtstiffs-1000]

Is MC your main or master circuit?
Switch it off and see if you still have any power.

In the context of a home fuse box (or electrical panel), "MC" likely refers to a "Main Circuit" or "Main Breaker" label, indicating the primary circuit that supplies power to the entire house.

 

[Robobrainiac]

You could take the panel cover off and see if there are any wires attached to the mystery breaker.

The last time I had the cover off I remember it has some pretty large wires going to it.

 

[Robobrainiac]

There should be a fuse/disconnect outside for the AC as well, that might have the amperage on it? But yes, the furnace and the AC are entirely different units electrically.

The ac unit outside does have a box with breaker/switch in it on the side of the house right next to the assembly.

 

[Robobrainiac]

Is MC your main or master circuit?
Switch it off and see if you still have any power.

In the context of a home fuse box (or electrical panel), "MC" likely refers to a "Main Circuit" or "Main Breaker" label, indicating the primary circuit that supplies power to the entire house.

MC is not main circuit. I have a large "Main Principle" on the label at the bottom of the box that turns everything on and off.

 

[Robobrainiac]

This is a closeup of the sharpied label on the mystery breaker.


It looks like at one point it said well pump and then in a separate handwriting it looks like it says farm.

 

[Fatsquatch]

This is a closeup of the sharpied label on the mystery breaker.


It looks like at one point it said well pump and then in a separate handwriting it looks like it says farm.



View attachment 462310

Instead of farm it might say furn as in furnace

 

[Tramguage1]

There should be seperate 220 breakers for the outside condenser and another for the unit inside the house.
Do you happen to.have a subpanel somewhere in the house or an outbuilding?

 

[JenElio]

The ac unit outside does have a box with breaker/switch in it on the side of the house right next to the assembly.

That should just be a disconnect, not a breaker. The condenser (outside) and the air handler (inside) should both have their own designated breakers. Maybe you have/had a small sub panel feeding a shed or similar???.....

 

[WagginTail]

Instead of farm it might say furn as in furnace

I agree

 

[Robobrainiac]

There should be seperate 220 breakers for the outside condenser and another for the unit inside the house.
Do you happen to.have a subpanel somewhere in the house or an outbuilding?

That should just be a disconnect, not a breaker. The condenser (outside) and the air handler (inside) should both have their own designated breakers. Maybe you have/had a small sub panel feeding a shed or similar???.....

The outside box is a disconnect.

7/5 labeled furnace turns on and off the interior HVAC portion. It shuts down the thermostat and blower.

The outbuildings I have on property all have their own power sources.

 

[Robobrainiac]

I was able to verify shutting off the M C or A/C labeled breaker turns off the exterior A/C unit. The interior "furnace" portion stays running. So I believe the M C is the A/C.

 

[Hometeam]

The sharpied breaker is a complete mystery to me. When it is cold outside that breaker can be warm to the touch. As if it is doing something. When our water has frozen I have found that breaker tripped maybe 2-3 times in the five years we have lived here.

This statement makes me think that breaker is hooked to some 220V heat tape that is wrapped around your water line somehow. How deep is your water line. Ours here are put in at 48” or deeper.