I read a thread earlier basically saying a fridge should not be run on an extension cord. I was curious why that is. And how it would be different than having the same distance ran in the wall to an outlet. But I was really more curious if it would be any safer for a mini fridge instead. I am building a fermentation chamber and kegorator out of a mini fridge. The fridge plugs into a thermo controller. The thermo controller has a 3 foot power cord on it. This is a very popular thing to do, people do it all the time without burning down their house or garage. I may have to put another 1 or 2 foot extension between the controller and fridge cord. All this will be tucked out of the way and secured.
An extension cord
- is usually lighter gauge than house wiring
- introduces an additional connection, another opportunity for reduced voltage
- the connection may be exposed to dust and/or liquids
- the connection can easily be loosened exposing open, live conductors
- the connection may be in a place more accessible to children, pets, falling metallic debris, vehicle tires, etc.
The lighter gauge wire may lower the life of the fridge's motor by not providing full voltage especially during motor starting. In severe (though rare) cases, the light gauge wire could be a fire hazard if the fridge runs especially hard, like when an overabundance or lack of refrigerant oil causes the pump to work hard.
In commercial and industrial sites (at least around here), fire inspectors require immediate removal of extension cords from anything vaguely permanent looking.
If your kegerator is going to be in use for some time, why not install a real outlet in the right place for it? In a garage or utility area, the wall doesn't (usually—depending on your wife) have to be perfectly patched. The wire, outlet, box, nails, etc., won't set you back more than about $15.
The issue comes down to using extension cords that are not rated to take the power of the appliance. A fridge connected to a 20A circuit may fry an extension cord rated for 10-20A.
Many many people have to run extension cords for fridges. Is it a best practice? No. I would first check your fridge's manual and see if there are instructions or wiring a new cord. If there isn't make sure that the extension cord you go with is rated for 20A - I have bought this cord and was happy with it. I have ran everything with it. Also note that if you are making this a "permanent" connection then I would make sure there is no chance of the cords becoming partially dislodged.
In reality your mini fridge is at most a 12 amp draw or designed for a 15 amp circuit. A 14 gauge cord will be fine in this case. Most folks don't realize that cords like sjo, so, are actually rated higher than standard wiring for example a sjo cord with #14 wire is actually rated at 18 amps per the NEC table 400.5.a.1. So this will provide enough capacity for the inrush current especially since it is a small unit and a short cord. Depending on the actual draw it is possible an even smaller cord could be used for example a 16 awg cord is good for 13 amps so if the draw on the mini fridge is less than 10 amps this size cord would work without problems.