Recently, I moved in a 1 bedroom apartment unit with no already installed AC unit and microwave oven. Thus, I am thinking of installing them by myself, but I noticed a problem. The capicity of my circuit breaker box is not enough.

In the circuit breaker box, I can see the following breakers.

  • 20A for the kitchen appliances. (1 outlet for the fridge, 1 duplex outlet for the countertop)
  • 40A/40A double-pole for the range
  • 2 linked 20/30A double-pole for heat and heated water
  • 15A for living room, bedroom and bathroom.

On the countertop, I use an electric kettle and a toaster. Thus, I think together with the fridge, this already reached 80% of 20A or more of that. Thus, I only use one appliance at a time except the fridge. Moreover, physically, the countertop has not enough space for a microwave.

Thus, the 15A circuit breaker should for the all other electric devices/appliances AND lighting AND a microwave oven AND an AC unit. Definitely, it is not possible.

I already have inquired this situation to the landlord, so I am waiting their response. However, I expect they also do not have some good solutions for this situation because there is no way to change the current capacity and wiring without full renovation of the apartment complex.

This is a pretty old apartment complex, and I think it was origianlly built not as an apartment complex. Thus, I understand this situation, but I will need at least a microwave oven.

I would like to hear some thoughts/suggestions from this community. I will really appreciate any of your comments!

  • What is your question? You might actually be fine. A microwave is typically around 1000 watts, and many window air conditioner units use under 600 watts. Make sure you're using LED bulbs.
    – KMJ
    Sep 8, 2023 at 20:35
  • Microwaves and AC units come in different sizes, so should at least be able to do the same as the toaster and kettle.
    – crip659
    Sep 8, 2023 at 20:39

3 Answers 3


Microwave Oven

Simple. Use a countertop microwave oven just like you use the toaster and kettle. Physically no space? Get a small cart. I used to use one for that purpose, after redoing my kitchen (giving a permanent place for the microwave oven) it is down in the basement as extra storage. Plenty of flat-pack things and you may even find one for free (or nearly free) used. Then you plug it in the kitchen and just don't use it at the same time as the toaster or kettle. Problem solved.

Air Conditioning

This is a bit more complex. But since you have a 20A circuit for heat, that may be the answer, as that is certainly enough for an air conditioning unit. To figure that out, we'll need more details, and it will likely require some professional installation unless the heat is plug-in (which is not usually the case). The key is that you would never run the heat and the air conditioning at the same time.


Being on the committee of a body-corporate for one of my apartments, I have a little bit of insight.

  1. You cant upsize the breakers as the cables to your apartment would have been speced for the breakers you have.

  2. You can put on other load, but you run the risk of the breakers flipping, not just in your apartment, but also the breakers on the floor riser. Which will annoy other occupants and the landlord. If they have to call an electrician, it may cost you. While, individually, the appliances may be all right, but if you forget and turn too many things on at once, combined with their inrush current, the breakers may flip.

My advice would be, dont do the AC unless you employ an electrician to review it first.

If you use the same socket for the microwave and the toaster, and unplug one before plugging the other, it could work for you. There are also combo appliances around,meant for apartments, so have a look.


The kitchen appliances are easy. The vast majority of kitchen appliances are in the business of making heat. In Europe they range 2000 watts, 2500, even 3000 watts, because European circuits support that. Over in America they are capped at the 1500 watt UL limit for a 15A (1800W) circuit, so essentially all of them run balls-out at 1500 watts. A 20A circuit is 2400 watts, so presume you will NOT be able to run 2 heat appliances on 1 circuit. Unless you have nameplate data telling you otherwise.

For instance, 2-slice toaster mechanisms are designed to be installed in a pair in a 4-slice toaster, so they use 50% of the 1500W, or 750W. Slow cookers don't need anywhere near 1500W, so may run 300W. I have a cheap hot plate that is 900W. A simple refrigerator pulls 120 watts or so when it runs (maybe 300W for rare defrost). Know your numbers and stay within limits.

On your A/C unit, disregard the trendy 1-hose portable units, as they are very inefficient by design and that means they take way more power than they have to. Use absolutely first choice an efficient window unit - some 6000 BTU units only take 400 watts! You could run 2-3 of those on a 15A circuit.

Or as a reluctant second choice, use a 2-hose portable, which solve most of the worst efficiency problems. (And the hoses might be concentric, so don't use your eyes to decide if it's 2-hose, read the spec).

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