Originally Posted by Raugustin
a)Current is something that is drawn through the breaker from the load, it is not a surge. A surge is typically a spike on the sinusoidal waveform and is usually a result of transient switching of reactive loads or other anomalies on the line. When we talk about burn-outs of motors, specifically compressors, we talk about the effects of current and surges. Voltage surges caused by reactive loads being switched or transients will pass through a breakers and will weaken the insulation of motor windings...it may take many incident and may not effect the motors right away but they will, in time, effect the insulation of the windings. You may also have a catastrophic surge or spike created by lightning or a utility failure that could damage the units in a single event, however those are very rare. When voltage is reduce for a significant time in an induction motor, the current will increase and the slippage will also increase resulting in reduced speed and a significant increase in heat and the compressors in both the refrigerator and AC will rely on their internal thermal protection which is designed to shut down the motors when this happens. The increased current could also trip the dedicated breakers before the thermal protection is activated, breaker usually trip very quickly, a few milliseconds once the threshold is reached. So there is already protection provided for under-voltage and short circuit conditions and inadvertently, yes, circuit breakers and current have played a significant, but maybe indirect, part in this conversation.
The term 'surge' has a defintion so varied that no more than two posters are using the same defintiion. For example, a highly regarded professional on this subject says: "The IEEE ... has adotped a wored surge to denote an overstress condition that has a duration of less than a few milliseconds". So even the Progressive that takes far longer to respond is not doing surge protecton.
Your computer declares a surge when a USB device draws too much current. Some motherboards declare a surge when its motherboard voltage varies too much while the computer continues working normally. Which 'surge' is everyone discussing?
Numerous anomalies exist including frequency variation, harmonics, EMC/EMI, compromised neutral, voltage variations, floating ground, sags, brownouts, RFI, etc. Even a sag and brownout are different anomalies.
Which ones are harmful? Nobody can say without numbers. Subjective claims are why both scams and contradictory claims exist. 'Surge' is so easily and intentionally subverted to even get the naive to promote myths.
MOVs are cited as a solution without first defining what the MOV actually does. In some devices, MOVs only protect from transients that typically cause no damage. In another device, MOVs work by connecting that anomaly to something completely different that does the protection. We know this. MOVs only degrade when grossly undersized. When used in situations that even violate specification numbers in MOV manufacturer datasheets.
A Progressive addresses one anomaly. A protector at the pedestal is for another and different anomaly that might even damage the Progressive. Which device is needed? First the anomaly must be defined by numbers. Including size of and frequency of each anomaly. The Progressive is for an anomaly too often found in campgrounds. And rarely seen in homes.
Some motors have that internal protection. Others do not. Utilities either provide voltage within a narrow range. Or disconnect power. To maintain voltage that might otherwise harm electric motors. Campgrounds sometimes do not do that (and may not even understand the problem). One reason why many use a Progressive to protect from a surge that really is not a surge.