petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
Anyone ever have one catch on fire?
Anyone ever have one catch on fire?
Anyone ever have one catch on fire?
We had an almost brand new one that failed in the filed last week when the power was turned on for the first time. Just started smoking according to the guy starting it up. Looks like one or two of the 4 MOVs went south.
Maybe just a bad unit.
Not sure if the lady wet her pants on that one, she was visibly shaken, that's for sure.
But they were pleasantly surprised that we could restore power within a couple of hours, and find only minor damage.
Opening the windows for a few hours to air out the bad smoke smell, and they were able to remain in their home.
They were afraid the whole place needed rewiring and they would have to live out of a motel room for several days.
A surge protector like a circuit breaker can explode if its rating is exceeded.
Whether a protector "explodes" or not can depend on how the upstream OCPD functions.So a surge protector and a circuit breaker can 'explode' when exposed to it's rated - or even less - voltage or current, respectively. (Of course the argument can be made - and that statement would be more accurate - that when the failure occurs the device is no longer rated for it's original value.)
Whether a protector "explodes" or not can depend on how the upstream OCPD functions.
For small (i.e. short duration) surges just having the protecto clamp may be enough to reduce the voltage that other loads see without actually tripping an OCPD. In that case the protector has done its job.
For larger surges with a very high voltage and current source, the protector may clamp and trip the OCPD on instant before being damaged itself.
For situations in between, like a lost neutral, the protector may have to break down completely and short out before it can pull enough current to trip an OCPD.
I assume that in the case of the mobile home the main CB opened, and that was what saved the rest of the appliances?
When you have a bike (motor or pedal) accident and your helmet saves your head, most people are not annoyed at having to replace the helmet, no matter how good its condition may appear to be afterward. They need to think of a surge protector the same way.
Just to be clear: surge protectors are designed to protect against high voltage and OCPD's react to high current.
Absolutely, but if the high voltage is sustained rather then a pulse, the protector will eventually fail, and you can only hope that the fault current through the OCPD has tripped it by then. Once the protector is thoroughly burned out, it can't hold the voltage down any more.Just to be clear: surge protectors are designed to protect against high voltage and OCPD's react to high current.
Absolutely, but if the high voltage is sustained rather then a pulse, the protector will eventually fail, and you can only hope that the fault current through the OCPD has tripped it by then. Once the protector is thoroughly burned out, it can't hold the voltage down any more.
Just like a fuse or breaker has an inverse I T curve, the protector has a maximum energy it can deflect, which is the product of current, voltage and time.
If you are fortunate the I x T that the protector can withstand will be greater than the I x T product that trips the breaker.
A much more common fault, where a protector is expected to be effective, is a very short term surge, like a lightning induced pulse on the line. In those cases, with or without an OCPD, the protector will be able to shunt the surge down to a tolerable voltage. And there is nothing about such an event that, with or without a protector, would trip an OCPD. (Unless some of the loads were forced to act as surge sinks and they failed by shorting!)
The only situation in which they can interact to give complementary protection is the sustained but limited overvoltage, of which a lost neutral is one example.
...I assume that in the case of the mobile home the main CB opened, and that was what saved the rest of the appliances?...