I still think it’s the compressor causing the problem. Trying it on a different circuit if possible would help.
I think it is the compressor and I will try another circuit.
That is not likely going to solve anything.
The unit has 2 main components; the fan and the compressor. The fan draws a small fraction of what the compressor draws, whether at inrush/start up or running. Its almost always the compressor!
The A/C unit should be on a dedicated circuit anyway, so putting it on a dedicated circuit won’t hurt.
But it won’t help either.
If it was tripping while running I’d say you might have too many loads on the circuit. Changing it then might be the answer.
If its tripping at start up, however, that’s a different problem. (and a different fix)
An A/C system that draws 15 amps while running may draw 50 amps or more for a split second during start up. That inrush current is the source of the dimming. That is a very common situation, and its normally not dangerous… (although aggravating)
There are things the OP can do----like making sure the A/C is running properly, adding a hard start, and making sure all wiring connections are tight.
Or that is what happens when wires in receptacles are not firmly attaches to the screws on each wall receptalce. The triiping circuit breaker an indication of a wiring defect.
Changing power source might identify good and bad wire cirucuits. And still the problem - that defective circuit - must be fixed.
Do the numbers. The air conditioner is rated at 1020 watts. 15 amp circuits are (120 volts times 15 amps) 1800 watts. That light duty circuit should be more than sufficient - lights should not dim. A 20 amp circuit is (120 volts times 20 amps) 2400 watts. (Actual rating is derated). Again, should be more than sufficient power to handle that air conditioner. But if wiring somewhere is not firmly connected, then the air conditioner will draw excessive current.
Again, this sentence should be heeded because it comes from a better informed source. Dimming or brightening lights may also be a symptom of a human safety problem. Would be your only warning.
lights dimming for a second when a large motor starts can happen in wiring that is up to code and can be safe.
lights staying dim while the motor runs indicates a problem.
No circuits should significantly dim even when an air conditioner starts. None. It is unacceptable and not necessary. And may be long term harmful to that motor. BTW same also applies to laser printers.
That 50 amp startup current is already calculated in the design of 15 amp wires and in what makes circuit breakers trip.
For example, light bulbs can draw eight times more current on startup. And not cause voltage problems for other devices, blow fuses, or trip breakers. In reality, a 15 amp circuit breaker takes far more than 15 amps to trip. All part of a well understrood relationship called “I squared t”. And which is well beyond the scop of this dicussion.
One common problem is wiring connected to the ‘back stab’ hole found on wall receptacles. One example of why dimming happens and why informed homeowners move those connections from a ‘back stab’ to be firmly attached to receptacle screws.
Everyone with no technical knowledge can inspect for that defect. Remove the receptacle cover. Look at the receptacle side. If wires are not attached to screws, then the homeowner has something he wants fixed.
Moving the air conditioner to another circuit can provide useful informaiton. That is not a fix. That is how to define the problem. Fixing is always a second step - after the defect has been identified.
As a practical matter this is not true.
It is extremely for an A/C system to be on a dedicated circuit. When it is a central system it is always 220V and almost always on a dedicated circuit. When it is a 220V window unit it is almost always also.
Smaller units may or not be on dedicated circuits, (115V) although many are. It is true that a loose wire will cause current to surge (whether at start up or running) it is not always due to loose wiring or a wiring defect.
And then view the numbers. 1020 watts. Well below the rating for a 15 amp circuit. And even significanlty below the rating for a 20 amp circuit. This unit should work fine on any circuit because it is so small.
A lot of people are apparently very confused about how a home UPS unit works.
It’s mainly not going to work because a computer UPS does NOT provide continuous DC>AC from the battery. The battery is OFF line in home UPS units until the electricity goes off. It then very quickly switches to the battery in case of an outage, but it’s not going to work as a load buffer as the battery is not engaged by the unit pulling too many AMPS, but by the lack of AC input.
Many codes would require that circuit to be on a dedicated circuit, although for 115V appliances it often isn’t. The watts/ running load amps are not an issue. If I understand the OP, the breaker is tripping at start up, where the LRA may be much higher than 1020 watts.
If it is happening at start up it may be due to loose wiring. Its more likely due to a compressor that is losing lubrication and is ‘hanging up’ at the point of start up—causing extended locked rotor amps.
I think we largely agree. I think its a good idea to have the wires on receptacles checked and tightened. I am simply saying that this may not be a result of a loose wires, and may not be dangerous.
a plug-in AC should not use more than 80% of the current rated for a dedicated circuit or 50% of the current rated for a shared circuit.
Actually, there are two kinds of UPS’s. One kind which the batter switches on during a power outage (standby), and the other where all or most of the power is supplied from the UPS (online).
A standard circuit breaker actual takes a single draw of 10,000 amps to trip it. The lower ratings of 15, 20, etc amps refer to continuous draw. If your AC unit is tripping the breaker on start up there is a problem with the unit or a problem with the breaker. Tightening everything up along the way my help alleviate it but I wouldn’t put my money on that solving this.
As I am electrically inclined swapping out the breaker would likely be my first course of action. For those who are not comfortable opening up electrical panels or have the good sense not to, seeing if you get similar results plugging the unit into a different circuit is a good idea.
I agree. IME, it has been more often than not an issue with the compressor than a weakened/faulty breaker, although I’ve seen both.
That’s why I made the point about it being a home computer UPS. While some industrial and commerical type units may do this no home type computer UPS is designed to provide continuous power from the battery to the inverter.