Not that I'm encouraging anyone, but it has baffled me since I was a wee child.

Just how do you get the penny into the fuse socket without electrocuting yourself and have it STAY in there? Did people shove the coin into the socket and screw the burned fuse on top of it?

I've been trying this with a vertically mounted lampholder (disconnected) and USA coins of various sizes.

A 25 cent piece seems to fit the best....but it tops over and still falls out.

Have any of you run across things like this in the trade? Are there any pictures?

I've run across cartridge fuse holders with pieces of #12 wire across the clips.

I would never post this sort of thing on a DIY board but since I'm among pros and semi-pros here...I assume that this is reasonbly safe to ask without giving anyone ideas?

Sven,
Edison base FUSE holders, used to have a slightly different configuration than the bulb holders. Same thread though. An old fuse holder had the little "button" spot for the buss side of the fuse, and it nearly overlapped the screw shell side, which is, of course the load. EASY, put a penny, or other coin (not good to use nickels, when they used real nickel, it tended to get hot under load) and screw the burned fuse over it, it usually had no problem making contact.

As for the wire clipped on both ends......... that REALLY worries you when it's a 7,200 or 19,900 volt fuse, but hey, the American Electricians Handbood still lists the amperage a conductor will "fuse" at, but I don't have the book with me to give the section.

The first fuse was a piece of wire between two binding posts. I have removed these old panels, wish I had kept one now, just for show and tell, and ya just had to be careful not to use too big a piece of wire. Can still be handy in a true emergency.

That’s supposedly the idea behind NEC “type S” nontamperable fuses. Pennies are too large for them, and each current rating is intended to be noninterchangeable… 15A, 20A and 30A can’t be easily swapped. http://www.bussmann.com/library/bifs/1032.PDF but others make ‘em too.




[This message has been edited by Bjarney (edited 05-16-2003).]

Heck, George, I've got an old copy of the AE Handbook and still can't find it.
I have, though, had numerous instances of fire alarms connected ahead of main where I had to explain that the specs said not larger than a #8.
They all seem to think that any spec gives a minimum size, never a maximum...S

ran into a strange one once. a receptacle had overheated and burned when i tried to turn off the circuit none of the fuses would kill it I also noticed that the lights where the panel was never went out either.On further investigation someone had removed the paper washers at the bottom of the fuse holders so every circuit in the house was basicaly tapped right of the main

AEH, 12th edition Page 4-32, 13th edition Page 4-39, Figure 48A in all gives the appropriate size wire for fusing.

Once read in a newspaper or other non-technical rag that a penny stuck into a fuse holder would blow at around a thousand amps. I suspect that the branch circuit 14 gauge wire would melt first

These are the cat's meow for getting that pesky 60-amp service rerated to 600!

Bjarney,
Aahh, the mysterious "solid neutral".

Redsy, if you're good, a stack of pennies could replace a 60A/250V cartridge fuse.

Bjarney,

Are those things for real? What in blazes are they used for and ... why?

Yes, they are a real product. An example of their use may be for a disconnect on 120V fuel-dispensing motors—one case where the hot and neutral are both required to be switched. The other situation could be converting a fused-disconnect switch into a non-fused switch, possibly for packaged HVAC-R equipment where mechanical codes require local isolation. http://www.bussmann.com/products/accessories/Group2.asp about half-way down the page. The complete listing is http://www.bussmann.com/library/docs/FullLine_Cat.pdf {6MB} page 207—listed up to 600-amp 600-volt.

Presumably it would also be acceptable to use these with a corner-grounded delta service and regular 3-phase switchgear?

Steel mills were notorious for using bolts in the motor disconnects, they'd rather smoke a motor than shut down a line.
A lot of their practices were suspect at best, like one company needed room for expansion so they started dumping slag in Lake Erie after awhile it was more slag at where they werer dumping than water so they would build new buildings on top of the slag, problem was most of the machines had 2 to 3 feet of water around them, the operator station was raised so he could see what he was doing and be out of the water. In the winter the water would freeze because there was not any heat except the heaters for the gearboxes, Thank God for OSHA .. they finally shut this place down. at least the expansion practices and the lack of heat.

Sven,
The problem may not have been how to get the penny in, but how do you get it back out again?


The problem with electricity is that it almost always works.

Many years ago while teaching a class for "harry homeowners" I had a guy give a complete explaination. Take a pencil, put a wad of gum on it, stick the penny to the gum and insert. Give a quick twist and the pencil and gum come out. Screw in a blown fuse in to hold the penny in place. If the gum stays in...forget it (so he said) it'll melt away. (Probably during the fire). Honest to gosh... that's what he explained to the class.

My trade school teacher once told me of a silly fool who used a bullet in place of a fuse.

True story.

I knew there were handguns with electrical firing, but an electrical panel that is firing at you? Scary stuff!