Voltage fluctuations and an electrical feed which is still offline are some reasons why a freezer doesn’t work after a power outage.
Voltage fluctuations which include unusually high and low voltages can damage components such as motors and electronics inside the freezer causing it to not work.
If the property is on two or three phase power then it is possible that one phase is still offline (the phase offline would normally power the freezer). In this post I will go into more detail about these three different situations and how they affect a freezer from an electrician’s perspective.
Freezer Wiring & Fault Finding
The key electrical components affected by a power outage inside the freezer include electric motors (for the refrigeration) and electronics.
Both of these components are affected when the voltage gets too high or too low. A freezer is designed to work at a standard voltage found at any power outlet. This is typically either 110-120 volts (USA) or 230 volts (UK/AUS/NZ).
The power outlet which supplies power to the freezer via a plug is powered by a cable originating at the switchboard. At the switchboard there should be breakers designed to shut off power to the circuit if something goes wrong. This could be a short circuit or overload – both of which can cause fires. For this there should be a MCB circuit breaker or a fuse.
There should also be a RCD which is designed to shut off power if a fault that can give someone a shock occurs. For example, if a fault occurs with the freezer which could give someone a shock, the RCD will trip as a response.
Neither an RCD or MCB breaker will protect the freezer from an unusually high voltage. In this case, a surge protector is required.
Surge Protector For A Freezer
A surge protector works by diverting high voltages away from appliances like freezers and discharging it to earth.
A surge protector can either be installed in a switchboard or be located on a device such as a multi board. If the surge protector is on a multi board it will only protect whatever appliance is plugged into it. If it is installed in the switchboard it will protect all appliances in the home. Many other appliances in the home can be affected by power outages such as dryers and internet.
A surge protector is a good investment when you consider the cost of replacing your appliances.
Freezer Not Working After Power Outage? – Reason #1
High Voltage Affecting Freezer
Likelihood: High – transient high voltages occurring before the power outage are a common reason why an appliance won’t work. Contact your local company which manages the power lines for more information on the cause of the fault.
Fixable? As high voltages are likely to damage many components at the same time it may not be economical to fix but instead replace.
High voltages may only occur for an instant before an outage but this short period of time is enough to completely fry electrical parts of the freezer. This can include both the motor and electronics.
Electronic components on a circuit board such as resistors, capacitors and semiconductors fail when the voltage exceeds their stated limit.
Capacitors in particular work within a very narrow voltage range. When this is exceeded they tend to short out. This leaves a swollen and melted area on the capacitor or circuit board. It may be possible to smell a metallic or fishy odor as a result of electronic components burning out.
For electric motors involved in the refrigeration, high voltages cause damage to windings if the motor isn’t rated to run at that voltage. This causes the freezer to not work.
As high voltages can damage many parts of the freezer simultaneously, it may not be economical to repair the freezer versus replacing it.
Freezer Not Working After Power Outage? – Reason #1
Low Voltage Affecting Freezer
Likelihood: Moderate – Contact your local company which manages the power lines for more information on the cause of the fault.
Fixable? Check for a tripped circuit breaker in the switchboard. It may be possible that the freezer (and other appliances on the same circuit) have tripped out the breaker on overload. Resetting may resolve the problem.
Low voltages can occur due to a fault with the power lines or nearby transformer. The effect of unusually low voltages on appliances may not be as dramatic as high voltage but can be just as profound. Low voltages mainly affect electric motors which are present in the freezer. These low voltages cause motors to draw more current to compensate. This extra current causes the windings of the motor to generate more heat. Eventually the motor will burn out causing the freezer to fail. Hopefully before this occurs a breaker trips. Check the switchboard for a tripped circuit breaker. Resetting it may get the freezer to work again.
Freezer Not Working After Power Outage? – Reason #3
Lost Phase
Likelihood: High – if your home is on two or three phase power. Contact your local company which manages the power lines for more information on the cause of the fault and when the lost phase will come back online.
Fixable? Yes, wait for the lost phase to come back online.
If your property is on two or three phase power it means that you have two or three independent electrical feeds powering your property.
If one electrical feed is lost it can mean losing power to a part of the house. This could include the wall outlet which powers the freezer. By plugging the freezer into a different wall outlet (via an extension cord) you can check whether this is the cause or not. It is also possible that the wall outlet has failed too.
Electricians Perspective
Transient high voltage before a power outage is a common reason why appliances such as freezers won’t work. This is because components of the freezer such as any electric motors or electronics can handle these voltages. The best solution to prevent this in the future is to either install a surge protector or get a surge protector multi board to plug the freezer into.
We Fix Faults is an electrician blog dedicated to finding and fixing common household electrical faults. If you have any questions about this blog send us a message here.