December 2010
M T W T F S S
« Nov   Jan »
 12345
6789101112
13141516171819
20212223242526
2728293031  

Archives

Categories

The 100 amp fuse

I found this fuse in an old electrical panel that we were removing from the WICC generator shed.  This was the original service entrance for the site as it was built in 1932 or so.  The generator shed had a manual three pole two position transfer switch, which was fine back in the day that a licensed transmitter engineer was on site whenever the station was on the air.  The generator, according to the old records I could find, was an upright 2 cylinder slow speed engine with a belt driven generator.  They were mounted on concrete pads about 5 feet apart.  The motor had a big fly wheel that was hand cranked with the compression off.  Once a good head of speed was built up with the hand crank, the compression lever was thrown and the engine would start.  Alternatively, the procedure was tried again.

That was all replaced in 1971 when the transmitter site underwent a major upgrade.  The old electrical service was bypassed and abandoned in place when a new meter and panel was installed on the transmitter building.  The old service seems to have been frozen in time, untouched for forty years.

Kirkman Engineering renewable fuse

Kirkman Engineering renewable fuse

This fuse is a Kirkman Engineering Company and has a manufacture date stamp of January 1945.  It is a replaceable link AKA “renewable” fuse.  In has “peak lag” links, which I think would be called “slow blow” today.  Peak lag may also indicate a large inductive load, which would lower the power factor.  What I find interesting is that someone, once upon a time, placed two 100 amp links in parallel, then crossed the 100 AMP label out and wrote “200” on the fuse body.

Kirkman Engineering fuse links

Kirkman Engineering fuse links

The problem with this setup, the panel and wiring were all rated for 100 amps.  The wiring is #4 copper, and the transfer panel and switch are clearly labeled “100 amp, 3 pole.”  It would appear that the finger stock holding the upper blade in place was loose, causing the fuse body to overheat.  In fact, it became so heated that the case and the wood fiber holder are charred and missing.

Fortunately, there was never a fire.

The reason why we use properly sized fuses and breakers.

Be Sociable, Share!

2 comments to The 100 amp fuse

  • J. Aegerter

    In years past when a dollar was worth something, replaceable fusible links in fuses were popular. Federal Pacific made fuses with replaceable links and called them “ECO-FUSE”. They were of course ECOnomical rather than replacing the entire fuse. If the WICC site is wired with #4AWG copper it doesn’t meet the current (or years past) NEC for a 100 Amp service. It would have to be #3 AWG copper to be in compliance with the NEC in a commercial building. Only residential dwellings can use #4AWG for a 100 Amp service. There is a certain beauty of the old electrical power equipment, and AT&T was one to keep fuses feeding all of their microwave equipment. The higher interrupting capacities of fuses means less time lost to reset a breaker that may have unnecessarily tripped.

  • Paul Thurst

    It could well be #3 wire, it is cloth covered with hard rubber insulation, there is no gauge or temperature rating on it, I assumed #4. Everything is run inside of rigid metal conduit, so no corners where cut as far as I can see.

    The place is sort of like a museum, I wish the old Western Electric transmitter was still there.

Leave a Reply

 

 

 

You can use these HTML tags

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

Axiom


A pessimist sees the glass as half empty. An optimist sees the glass as half full. The engineer sees the glass as twice the size it needs to be.

Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
~1st amendment to the United States Constitution

Any society that would give up a little liberty to gain a little security will deserve neither and lose both.
~Benjamin Franklin

The individual has always had to struggle to keep from being overwhelmed by the tribe. To be your own man is hard business. If you try it, you will be lonely often, and sometimes frightened. But no price is too high to pay for the privilege of owning yourself.
~Rudyard Kipling

Everyone has the right to freedom of opinion and expression; this right includes the freedom to hold opinions without interference and to seek, receive and impart information and ideas through any media and regardless of frontiers
~Universal Declaration Of Human Rights, Article 19

...radio was discovered, and not invented, and that these frequencies and principles were always in existence long before man was aware of them. Therefore, no one owns them. They are there as free as sunlight, which is a higher frequency form of the same energy.
~Alan Weiner

Free counters!