Tempering/Preparing Fuses - Electrical Questions. Read Only. No more posting. - PlanetChristmas! Forums. Read Only. We've moved to http://talk.planetchristmas.com - The Forums of PlanetChristmas have moved to http://talk.PlanetChristmas.com
Outlet -> Net light set -> 100 mini lights -> 100 mini lights -> 100 mini lights -> Snowman, about 300 mini lights.
Mini lights are older, net light has a higher rated fuse.
So here is my theory, every year, if you plug light sets in the same order, every year, and add another string every season, the heat build up from being so close to an overload plus the sudden cold from the ambient air after shutdown will over time "temper" or "harden" the metal in the fuse to let it pass more current through.
The order first mentioned, did happen and I did add a little every year. the order above was the last time I did that. And no, I will never do that again, that was before I knew better.
So, if you understand the above theory, could it be applied to a to an almost overloaded home circuit breaker?
--Daniel L
P.S.- This thread was not started to ask a personal electrical question, meant to get a discussions on possible ways to unknowingly loose your overload protection.
I'm not sure you could temper the element contained within a fuse. The element within a fuse is generally lead which has a very low melting point. One of the reasons fuses are more reliable is that they don't deteriorate or loose calibration over time the way a breaker can.
A circuit breaker is a thermal device and under certain conditions can allow a higher current to pass through before tripping,
I will be seeing one of the engineering guys from Bussman (fuse mfg) in the next couple of weeks and I'll ask him what his thoughts are on this and if they have done any testing.
Tony
____________________ Do not meddle in the affairs of dragons, for you are crunchy and taste good with ketchup.
I believe mosst fuses would actually anneal through repeated heated and relatively slow cooling in air. To harden something you need to actually cool something faster like in oil or water where the heat transfer is much much faster than air. I have found this to be true with steel , copper and brass. I'm pretty sure the fuse element is mad from tinned copper. This may vary with fuse types. I have inspected the guts of many larger fuses that have broken or blown. Also the replaceable fuse links are all tinned copper. The tinning process keeps the copper from corroding/thinning over time.
Although the theory would stand to reason, it is sologistical reasoning only.
Because sologisticly we can harden metal by heating and cooling it doesn't mean fuses act that way.
Actually quite the reverse happens, a fuse that was overloaded will not sustain the same maximum overload the second or third or fourth time. In fact a fuse that has been overloaded many times may open (blow) under normal load.
Each succession of overload will make the fuse less tolerant of overload or current carrying capacity the next time by design.
As an aside, I'm curious how you make sure every string is in the same order every year . Other than some lights that I keep connected and roll up together, most of my lights get separated into individual strings, placed in large containers, and go back up in a new random order (and possibly completely different place in the display) the next year...
I'm pretty sure the fuse manufacturers have this issue covered, so I wouldn't worry about it. There's enough real, known display safety issues to think about. Besides, we should all be using meters to make sure our current loads are in spec, and not relying on fuses...
. Other than some lights that I keep connected and roll up together, most of my lights get separated into individual strings, placed in large containers, and go back up in a new random order (and possibly completely different place in the display) the next year...