Fluctuating high and low voltages preceding a power outage can have detrimental effects on a dishwasher.
Components inside the dishwasher such as electronics, motors and any control circuitry can be damaged with unusual voltages. The dishwasher can also not work if an incoming power feed is offline.
This post will cover 3 reasons why a dishwasher won’t work after a power outage and what you should do about it.
Dishwasher Wiring & Fault Finding
A dishwasher is an appliance containing several types of electrical components. This might include motors for washing and pumping water, control circuitry such as time clocks and thermostats, relays, solenoids and various electronics.
A dishwasher is designed to operate on a steady AC voltage supplied at the wall outlet. Damage to the dishwasher can occur if the incoming voltage changes due to a fault with the incoming electricity supply.
The wall socket (which the dishwasher is connected to) should be protected from electrical faults at the switchboard.
There should be a MCB or fuse which protects the wall socket (and dishwasher) from causing a fire due to a short circuit fault or overload fault. There should also be an RCD which will protect anyone from getting an electric shock from the dishwasher should the risk of one occur. It does this by shutting off power to the circuit once a certain current and time threshold is met.
The incoming electrical supply before it reaches your electric meter and main switch must be kept at a steady and constant voltage and frequency.
This is 110-120 volts at 60 Hertz (USA) and 230 volts (UK/AUS/NZ). Before the main switch and electrical meter it is the job of the local lines company to keep the voltage in this range.
Past the main switch and into your house it is the job of the electrician to keep the voltage within this range.
Weird voltages occurring with power outages are due to problems on the electrical network and are the domain of the local power lines company. Contacting them should give you more information about the fault.
Dishwasher Not Working After Power Outage? – Reason #1
Temporary High Voltage Damaging Internal Components
Likelihood: High voltage surges are a common occurrence with certain electricity supply faults in our experience.
Fixable? Depending on the extent of the damage it may or may not be economical to replace. The likely affected parts inside the dishwasher include electronics, the pump, the control circuits.
Dishwashers are designed to operate at a specific voltage range.
Every component, especially the insulation on wires is designed for the voltage to not be exceeded. When this happens, the voltage can essentially break through insulation barriers and cause damage to components.
Electronics are especially susceptible. Electronic components might include capacitors, inductors, semiconductors – all of which will be damaged with high voltage.
Capacitors are especially affected. When the voltage gets too high they will short out giving a loud cracking sound and leaving a burnt mark on the electronic circuit board. There may also be a weird metallic smell around as a result of burnt insulation
Motors are affected by high voltage especially at capacitors and windings. This is because these components are rated to work at a specific voltage – which when it is exceeded they begin to fail.
Dishwasher Not Working After Power Outage? – Reason #2
Temporary Low Voltage
Likelihood: Low but possible.
Fixable? Check for a tripped breaker in the switchboard.
If a fault with the electricity supply network caused an unusually low voltage it would affect the pump motor inside the dishwasher. The motor would draw more current than normal, heat up and potentially burn out.
It is possible that before this occurs a breaker trips in the switchboard. If no breaker has tripped then the windings inside the motor could burn out.
Dishwasher Not Working After Power Outage? – Reason #3
Lost Phase
Likelihood: High if the property is on three phase power.
Fixable? Yes, wait for the power to come back on or plug your dishwasher into another outlet further away. An outlet further away could be powered by a different phase.
If your property is on three phase power it means that there are three separate electrical feeds powering your house. Any one of these feeds could go offline during a power outage. When the power comes back on, not all feeds may be back online.
It is possible that the phase powering the wall socket for the dishwasher is still offline. Waiting for the power to come back on (for that phase) will fix the problem. Otherwise, try and find another outlet in the house to plug the dishwasher into.
Install Surge Protection
Surge protectors are small circuit breaker sized devices found in the switchboard. They help protect appliances and circuits from power surges.
They do this by diverting high voltages and discharging them safely to the earthing system thereby protecting appliances from damage.
As mentioned earlier, electronics such as those found in dishwashers, computers, wifi modems, fridges, TVs, microwaves (to name a few) are very susceptible to damage from high voltage. Surge protectors are also found on multi boards. These multi boards will only protect whatever is plugged into them.
Electricians Perspective
A high voltage spike damaging key components inside the dishwasher such as the electronics, pump motor or control circuitry is the most likely reason why it isn’t working after a power outage. Replacing the dishwasher might be the most economical way to resolve the situation if the damage is extensive.
If the home is on three phase power it will be worth checking if a phase is still out. This can be done by contacting the company which manages the local power lines.
We Fix Faults is a fault finding blog dedicated to discussing electrical faults that can happen. If you’d like us to cover a certain fault send us a message above.