Why would an old fridge trip a circuit breaker?

Question

I recently got an old fridge from a friend for use as a fermentation fridge for my homebrewed beer. The reason they were getting rid of it was because it was working fine, however it wouldn't cool below 8C, and they were quoted a few hundred dollars to fix the problem. However despite not cooling particularly low, the form given to them by the repairman has a box which is ticked which indicates that it has been tested and is in compliance with some sort of Australian/New Zealand standard, indicating that there can't be terribly much wrong with it.

We took the fridge over to my house, and after leaving it for a day or two upright (since we had to put it on its side to transport it), I turned it on. It immediately tripped the circuit breakers. As soon as I tried to switch the breaker back on, it tripped again. However I persisted, and after a few attempts to turn the breaker back to the on position, it stayed there and the fridge began to cool.

The problem here is that I need to use an external temperature controller to switch the fridge on and off in order to maintain the temperature I need to ferment my beer (roughly 16-20C). This presents a problem, since turning the fridge on and off will trip the circuit breakers.

I've tried moving the fridge to a different circuit, but that didn't solve things. I'm reasonably sure that the circuit I moved it to (the one for my garage) has nothing else on it, or at least whatever else is on it was switched off when I tested it.

Does this issue sound like something that's easily fixed, and are there any common causes for this sort of issue? Could it be simply high inrush current due to the age of the fridge? Could it be solved using some sort of inrush current limiter? Any pointers would be greatly appreciated.

Answer 1

I have a homebrew chest freezer in the garage, and a very understanding wife.

I am going to guess the problem is that the fridge has a 'freon' leak.

This leads to lack of oil in the freon line to lubricate the compressor. Which causes the compressor to overheat, and then a high temp thermostat opens.

The unit cools down, the thermostat resets, and it starts back up again.

The magic temp for overheating the compressor happens to be 8C inside of the fridge.

The reason for the breaker tripping immediately the first few times was from the compressor trying to start. Even though you gave it a couple of days, because of the leak, there is just not enough oil, in the right places, to start right up.

• I am guessing the fix is easy for an appliance guy, a bit of dye to find the leak, solder over it, and recharge.

Best of luck to you and your lager.

Answer 2

The first step is to determine if your circuits are adequate for the rated load of the appliance. This will require looking at the appliance for its load requirements.

If the circuit is sufficient for the rated load, yet the appliance is tripping it, then the appliance is out of spec and requires repair or replacement.

Keep in mind that adding additional electrical components between appliance and the outlet providing power does not repair the appliance and may simply mask a hazardous condition that may result in serious life safety threats such as structural fire or fatal electrical shocks.

Answer 3

Someone I know brought an old, working fridge from an old house to a new flat, where it would frequently trip the circuit breaker. The electrician said that this is fairly common with old fridges and modern (i.e. switched rather than a fuse wire) circuit breakers. There are simpler switched circuit breakers (e.g. without ground leak detection?) that might be less sensitive. In this case the fridge was replaced.