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Admin
I don't know, this story just left me cold.
Admin
My frist thought was "a 10 KW refrigerator?" Remember that the UPS was supposed to have way more capacity than theoretically needed. That extra power should have been enough to handle motor startup current. But perhaps it was stymied by the inductive nature of the startup load.
Admin
I would guess that it has to do with the high load AND the extension cord. I've heard stories of people with electric vehicles but no garage. So they grab a long extension cord and run it out to the car. I don't remember the reasons why, but I remember reading that it doesn't work well.
Admin
This isn't CodeSOD.
Admin
Someone may already have posted this because there are several comments held for moderation above, but shouldn't this have been posted in Feature Articles rather than CodeSOD?
Admin
I discovered when I tried to run my fridge and freezer off a spare 1000VA UPS - the continuous draw may be only ~300W for a domestic unit and comfortably within the unit's capabilities, but the startup current of the compressor (without a 'soft start' unit) can be twice that or more. And the planetary alignment when both fridge and freezer start together would overload the UPS. Thankfully I noticed before anything spoiled.
Admin
Any electrical cable has a resistance. Adding resistance causes the voltage to drop. Longer cables mean more resistance. So it's easily possible for a long enough extension cable to cause a 10 or 20V drop by the time the car is plugged in, and the charger cannot deal with that. Additionally, the amps that a car charger would pull even on a slow charge would probably melt a household extension cable - resistance also causes a heating effect when load is applied.
Admin
Extension cords, particularly the cheap, thin, indoor ones, aren't very efficient and if you try to run anything more demanding than a lamp through them they will lose a lot of power as heat. It gets even worse if the cord is "conveniently" tucked under a carpet or has the excess coiled up tightly in a corner. The problem isn't usually a loss of power on the far end, but rather the unexpected fire in between.
Admin
What The Fridge!
Admin
I am pretty sure that the fire is quite expected and that the problem is the stupid user who didn't. xD
Admin
What is CodeSOD, anyway? I never figured out what the "SOD" part was, so I always think of it as "Some sod writing sodding code which makes it in here"...
Admin
SOD is short for Snippet Of the Day. It looks like the post has been moved to feature articles as there is indeed not much code here
This also reminds me of that one article where the bathroom water heater was somehow plugged into a UPS
Admin
It's ColdSOD (Snacks or Drinks). Easy mistake.
Admin
I thought of that story as well.
https://thedailywtf.com/articles/crappy-wiring
Admin
A motor like the one in a fridge compressor can easily draw 5x normal running current when it starts up. This is with high side start protection - high side starts are really hard on the motor and can cause the motor to draw even more current starting up.
(High side starts is when the compressor stops and the high pressure side is still pressurized - so you're starting the compressor against a high load. This is why your A/C and fridge normally wait about 5 minutes before the compressor starts after a power outage, or from when the compressor last ran. The protection is either a pressure switch or more commonly (cheaper) a timer circuit that waits 5 minutes after getting power before turning on the compressor - from either a power outage or when it ran last.).
Admin
Thank you! That's one small mystery cleared up :)
Admin
Heh! Looking at the comments (specifically, the comment by SwineOne) in the other UPS-related story linked above by Dragnslcr, it looks like that one also was posted to CodeSOD before being moved to Featured :-)
Admin
Sure, who said CodeSOD had to be about computer code? These stories belong in CodeSOD because they are about violations of building or electrical codes. Makes perfect sense. (/s)
Admin
A place I used to work for had a generator setup that was actually pretty good... full auto switchover, plenty of capacity, fully tested, all good. The generators were located in the basement, but they had even allowed for the possibility of it flooding; they were fully capable of running fully submerged.
When the floods hit, some people were kinda smug about those underwater generators.
Then the flooding stayed for a while... and after a bit, they realized that while the generators did indeed run happily while fully submerged, refueling them underwater was a whole thing they hadn't considered.
Everything important is now in a professional, dedicated data center.
Admin
If they had any cod in the fridge, that would belong to the CodSOD category?
I'll see myself out.
Admin
So interesting to see from the comments how much of a factor the quality and length of extension cords is, as someone who's only ever lived with 230V supply, extension cord quality has never been a concern for me unless one is trying to run a ridiculous load on it, I would not even begin worrying about the cord quality (provided it passed basic standards, which all off the shelf cords here must) unless I know I'll be exceeding 3kW draw.
Admin
As I recall, the benefit of living in an area that uses 230V supply is less the quality of the extension cords and more the custom of having the cord itself include overcurrent protection. In the U.S., I commonly see overcurrent protection (embedded fuses) in holiday lights but seldom in anything else, so there is often a risk of the item having a lower limit than the circuit breaker.