A word of caution here, modern electrical codes specify GFI for all outside outlets.
Now if it snows or rains you stand good chances that the GFI will kick off the block heater circuit.
It's a bummer.
Local city snow contractor was plugged in but the extension he used was subjected to snow at the connection and he had a cold no start tractor.
GFI simply kicked out, they kick out at the slightest sniff of wet and snow is frozen 'wet'.
We intend to replace all those outside outlets with non GFI's as they are simply a major PIA.
On my tractor I use a wireless remote switch like a car 'key fob'.
I also parallel a witness light bulb* to confirm the heat is on.
Generally I switch 1 hour or so B4 plowing. If the engine is warm then the cab heater will cozy me.
(like I hate driving all bundled up and wearing gloves)
Before that I had a switched outlet with the switch in the clothes closet but I like the wireless better.
* I use an LED night light from the dollar store. (taped over the sensor to make it always hot, like permanant night time)
