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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Nathan Riddle on March 30, 2018, 10:42:35 AM
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ECM always has an interesting article or two. This one's a doozy :)
(http://www.ecmweb.com/sites/ecmweb.com/files/styles/gal_landscape_main_2_retina/public/Define%20Qualified_1_0.jpg)
http://www.ecmweb.com/ops-maintenance/12-reasons-why-electricians-should-always-be-looking-trouble/gallery?slide=11
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While running a power issue in a club, found bolts replacing the 100a fuses....
jd
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Back in the '70s I was repairing a custom fixture and found a length of aluminum round stock cut to length and used in place of a standard fuse. I charged an extra "stupidity tax" for that repair.
JR
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ECM always has an interesting article or two. This one's a doozy :)
(http://www.ecmweb.com/sites/ecmweb.com/files/styles/gal_landscape_main_2_retina/public/Define%20Qualified_1_0.jpg)
http://www.ecmweb.com/ops-maintenance/12-reasons-why-electricians-should-always-be-looking-trouble/gallery?slide=11
I suspect under heavy load or a short, those copper wires would vaporize :o
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I suspect under heavy load or a short, those copper wires would vaporize :o
Yes, we call that a fuseable link... ;)
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I have seen 1/2" copper pipe flattened on each end to fit in place of a 100 amp size fuse. Seems like more work thatn it is worth.
That said, there is a situation where a non-fused disconnect would be acceptable-if the upstream over current protective device is sized appropriately, sometimes code requires a disconnect "within sight" of a load. If that is the case here, the only real code violation is the fact that those fuse holders are certainly not listed to be used with pieces of solid wire!
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I suspect under heavy load or a short, those copper wires would vaporize :o
You might be surprised by how much current that takes... About a year ago I needed to DIY a small fuse to get an amp working until replacement fuses arrived. I macgyvered a single stand of the smallest wire I could find (30ga?) tacked across the blown fuse, but decided to look up it's fuse current and that was close to 10A IIRC. :o
(BTW kids don't do this at home).
JR
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Yep, fusing current for copper wire:
30AWG :: 10.2A
12AWG :: 235A
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Yep, fusing current for copper wire:
30AWG :: 10.2A
12AWG :: 235A
Those values are in free air, right?
Sent from my VS995 using Tapatalk
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Those values are in free air, right?
Based on Preece and Onderdonk.
https://www.powerstream.com/wire-fusing-currents.htm
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I suspect (and I have no way to prove this), but I'd bet whoever was there "needed" it to supply power and wanted something akin to a "fuse" and used the copper wire.
The bolts sound scary...
Based on Preece and Onderdonk.
https://www.powerstream.com/wire-fusing-currents.htm
This is schweet :) thanks!
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You might be surprised by how much current that takes... About a year ago I needed to DIY a small fuse to get an amp working until replacement fuses arrived. I macgyvered a single stand of the smallest wire I could find (30ga?) tacked across the blown fuse, but decided to look up it's fuse current and that was close to 10A IIRC. :o
(BTW kids don't do this at home).
JR
Been there, done that, more times than I will admit. But in controlled situations, NOT for a customer to take with them.
But NOT recommended.
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Based on Preece and Onderdonk.
https://www.powerstream.com/wire-fusing-currents.htm
That's great, but I don't see the fusing currents for a 1/4" nutdriver. ;D
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That's great, but I don't see the fusing currents for a 1/4" nutdriver. ;D
Hollow shaft or solid?
Toodleoo!
Ron Hebbard.
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Based on Preece and Onderdonk.
https://www.powerstream.com/wire-fusing-currents.htm
Can I print this out to show the AHJ why he should ignore my solid wire jumpers in place of fuses?
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HMwire has a pretty comprehensive table with multiple equations
http://www.hmwire.com/New%20PDFs/Fusing_Currents_Melting_Temperature_Copper_Aluminum_Magnet_Wire.pdf (http://www.hmwire.com/New%20PDFs/Fusing_Currents_Melting_Temperature_Copper_Aluminum_Magnet_Wire.pdf)
JR
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Can I print this out to show the AHJ why he should ignore my solid wire jumpers in place of fuses?
How about an inline "wire/fuse" holder that is protected by an appropriate (for wiring size/terminals/etc) OCPD? You could demonstrate how much current flows through (and with an infrared camera, show the heat) a conductor about to "fuse".
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How about an inline "wire/fuse" holder that is protected by an appropriate (for wiring size/terminals/etc) OCPD? You could demonstrate how much current flows through (and with an infrared camera, show the heat) a conductor about to "fuse".
Back in the day we called this a "smoke test".
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Back in the day we called this a "smoke test".
Smoking is on the downswing, Mike. ;)
Controlled destruction for instruction!
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Releasing smoke is a way to keep students awake...
JR
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Not to mention that the melted/exploded copper could start a fire.
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Not to mention that the melted/exploded copper could start a fire.
Yeah, and with enough amperage behind it this becomes an arc-flash. And that's very serious, indeed...
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I suspect under heavy load or a short, those copper wires would vaporize :o
Followed by an arc flash destroying the panel and anyone unlucky enough to be near it.