Many homeowners find themselves faced with a familiar dilemma – not enough circuits in the kitchen to plug in all their appliances. With a fridge, microwave, electric oven, dishwasher and more fighting for space, you may be tempted to double up and put the microwave and fridge on the same circuit. But is this a dangerous idea that could lead to electrical fires and other hazards?
This comprehensive guide will examine whether it’s safe to put a microwave and refrigerator on the same circuit.
1. Overloading circuits can lead to tripped breakers, blown fuses, appliance damage, and potential electrical fires.
2. Check the wattage or amp rating of the microwave and refrigerator to ensure the circuit can handle the combined load.
3. A 15 amp circuit should only have a microwave or refrigerator, not both. A 20 amp circuit may be able to run both safely.
4. Older homes with fewer circuits may require combining appliances but use caution and consult an electrician.
5. Never overload a circuit beyond recommended limits – follow manufacturer instructions and local electrical codes.
6. Signs like frequent breaker tripping, dimming lights, or warm outlets indicate appliance overloads.
7. For maximum safety, use an electrician to install dedicated, properly sized circuits for large appliances like microwaves and refrigerators.
Overloading Circuits Can Be Risky
Before deciding to combine a microwave and fridge on one circuit, it’s important to understand the dangers of overloading a circuit in general. Here are some of the potential risks:
- Tripping the circuit breaker – If too many high-wattage appliances are running on one circuit, it can trip the circuit breaker. This will cut power to the circuit until the breaker is reset.
- Blowing fuses – Overloading outdated fuse boxes instead of modern circuit breakers can literally blow the fuse and require replacement.
- Electrical fires – When too much electricity flows through undersized wiring, it can overheat the wires and start an electrical fire in the walls.
- Damaging appliances – Some appliances like refrigerators and microwaves have sensitive electronic controls that can be damaged or destroyed by power surges.
So in general, it’s best practice to avoid overloading circuits whenever possible. But in some circumstances, combining a microwave and refrigerator on one circuit can be done safely.
Factors to Consider
There are several factors to look at when deciding whether a particular microwave and fridge can safely share a circuit:
- Electrical usage – The power draw or wattage rating of each appliance determines how much electricity it uses. Lower wattage appliances take less power to run.
- Circuit amperage – The circuit must be rated for sufficient amps to run both appliances at once safely.
- Age of home – Older homes tend to have fewer and lower capacity circuits that may require combining appliances.
- Local electrical code – This code sets legal limits for overloading and modifications to existing wiring.
- Manufacturer instructions – The user manuals will indicate if there are restrictions on circuits.
Let’s look at each of these factors in more detail:
The first consideration is how much electricity the microwave and refrigerator use, specified in watts or kilowatts (1000 watts). Here are some general estimates:
|Average Electrical Usage
As you can see, both full-size refrigerators and microwaves are high-wattage appliances. Combining them on one circuit runs a greater risk of overloading. Smaller mini fridges use less power and may be safer to pair with a microwave.
Electrical power usage is measured in watts, while circuit capacity is measured in amps. A general guideline is that a typical household circuit provides 15 to 20 amps of power.
To find the amp rating of an appliance, divide the watts by the voltage (usually 120V in homes). For example, a 1000 watt microwave at 120V is 1000/120 or about 8 amps.
So a 15 amp circuit could potentially run a 8 amp microwave and a 5 amp fridge at the same time without tripping. But there is very little spare capacity to handle surge loads safely.
Age of Home
Older homes generally have 60 amp main electrical services and just a few small 15 amp branch circuits feeding the kitchen. This often forces combining multiple larger appliances on one circuit.
Newer kitchens will have 200 amp main services and dedicated 20 amp circuits for each major appliance like the refrigerator, microwave, dishwasher, etc. This makes overloading any one circuit much less likely.
If you have an older home, combining the microwave and fridge may be difficult to avoid. Use extra caution and consult an electrician regarding overload risks.
Local Electrical Code
Your local jurisdiction will have an electrical code that sets legal requirements for circuit loads. This code may prohibit overloading a circuit above a certain level depending on the age of the home.
For example, the code may forbid putting a microwave and fridge on one 15 amp circuit in a new kitchen, but allow it in an old kitchen lacking circuits. Always check your local code before modifying kitchen circuits.
Modern kitchen appliances come with detailed installation instructions in the user manual. Carefully check both the microwave and refrigerator manual for any restrictions on shared circuits.
The manual may indicate that the microwave requires a dedicated circuit. Or it may state that the refrigerator cannot be combined with other major appliances. Following the manufacturer guidance takes precedence over general rules of thumb.
Recommended Circuit Loads
Given all these factors, here are some best practice recommendations from electricians on shared microwave and fridge circuits:
- A 15 amp circuit should only have either a microwave or refrigerator, not both. This avoids potential overloads.
- A 20 amp circuit could run a 10 amp microwave and 5 amp mini fridge safely. But not a 15 amp microwave – too close to the limit.
- A 15 amp circuit in an older home wiring system may be able to handle a 10 amp microwave and 5 amp older fridge. But use caution.
- Never put a microwave and full size fridge on one 15 amp circuit. Only consider this if you absolutely cannot rewire or add a new 20 amp circuit.
Again, the wattages and amp ratings provided above are general guidelines. You must check the electrical usage details on your specific appliances before deciding whether they can safely share a circuit.
Signs of an Overloaded Circuit
Watch for the following symptoms if you do end up combining a microwave and refrigerator on the same circuit:
- Tripped breakers – Circuit breakers that flip off frequently under normal use indicate overloading.
- Dimming lights – Lights dimming briefly when the microwave or fridge kick on points to low voltage.
- Hot outlets – Outlets or switch plates that are warm to the touch show excess current flow.
- Motor problems – Microwave or fridge not starting or making buzzing noises from low voltage.
Any of these are warning signs to avoid using that circuit. Try redistributing appliances to underutilized circuits instead. Call an electrician if problems persist on overloaded circuits.
General Microwave Circuit Requirements
Since microwaves involve high-power cooking, they have some specific circuit requirements:
- Microwaves generally need their own dedicated circuit rated at 20 amps for best performance.
- Countertop microwaves under 1000 watts can often use a 15 amp small appliance circuit safely.
- Larger built-in and over-the-range microwave ovens may require a dedicated 20 amp circuit.
- Never plug a microwave into an outlet with other large appliances even if it fits. This avoids overloads during use.
- Plug microwaves directly into a wall outlet. Avoid using power strips, outlets with other plugs, or long extension cords.
Be sure to check the user manual for your exact microwave electrical requirements before installation.
General Refrigerator Circuit Requirements
Refrigerators also have specific circuit guidelines:
- 15 amp circuits are usually adequate for refrigerators under 800 watts. Measure the wattage if uncertain.
- Side-by-side and jumbo refrigerators often need a dedicated 20 amp circuit due to higher electrical demands.
- GFCI protected circuits are recommended for refrigerator outlets located near water sources.
- Avoid plugging in the fridge with other appliances on the same circuit to prevent possible overloads.
As always, consult the refrigerator installation instructions for the manufacturer recommended circuit specs and restrictions.
Wiring a New Circuit
If your existing kitchen circuits are overloaded, the best solution is to install a new dedicated circuit for the microwave or refrigerator. Here are some tips on adding a circuit:
- A licensed electrician is required to run new wiring in walls and modify electrical panels. Never attempt complex wiring on your own.
- Plan to add individual 20 amp small appliance branch circuits for microwaves, fridges, dishwashers, etc.
- Use heavy 12 AWG wire rated for 20 amp circuits. Run wires through walls from the panel to the outlet.
- A new 20 amp circuit may require upgrading from an older 60 amp to modern 100 amp or 200 amp main service panel.
- Expect to pay $150 to $300 or more for an electrician to add a new dedicated appliance circuit.
Upgrading overloaded wiring and circuits provide maximum safety, convenience and resale value.
Below are answers to some frequently asked questions about combining microwaves and refrigerators on circuits:
Can I plug a microwave and fridge into the same power strip?
No, you should never use a power strip for these major appliances. Power strips lack the proper overload protection and could overheat.
What if the manuals don’t list circuit requirements?
If appliance manuals don’t provide electrical details, use the general recommendations provided in this article as a guide.
Can extension cords be used for a microwave or fridge?
It’s not recommended. Extension cords can cause voltage drop over long distances. Use outlets in their permanent locations instead.
What should I do if circuits trip or show signs of overloading?
Redistribute appliances over additional circuits if available. If overloading persists, call an electrician about upgrading wiring and circuits.
If my appliances work fine together, do I still need to worry?
Even if no issues seem apparent, overloading circuits can lead to unsafe conditions over time. Fixing overloaded circuits should be a priority.
Combining a microwave and refrigerator on the same circuit requires careful consideration of appliance electrical loads, home wiring capacity, electrical codes, and manufacturer guidance. In general, microwaves and refrigerators work best on dedicated circuits sized for their power demands.
But in some older homes lacking sufficient circuits, it may be possible to safely run a lower wattage microwave and fridge together. Always exercise extreme caution when attempting to overload any circuit, and upgrade wiring whenever feasible for maximum safety and performance.