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#124171 - 08/20/06 07:50 AM Oddball Fuses  
electure  Offline

Joined: Dec 2000
Posts: 4,262
Fullerton, CA USA
Rewired has been exploring again [Linked Image]

I happened to stumble on this in the girlfriends apartment building(s).
The " 550" and " 575" amp fuses are in the main disconnect of two of the buildings, the " 380" amp fuses are in a third building which actually has TWO main services, one for the units, one (225 amp main breaker) for the house load and now disconnected electric hot water tanks. ( all had electric hot water at one time, only the other buildings brought in a 100A gooV 3 phase service for the tanks, all of which is now disconnected..

I found a couple good violations that I will post later

[Linked Image]

[Linked Image]

[Linked Image]

[Linked Image]

[Linked Image]

Tools for Electricians:

#124172 - 08/20/06 11:02 PM Re: Oddball Fuses  
napervillesoundtech  Offline
Joined: Feb 2006
Posts: 144
Naperville, IL, USA
Individual runs of copper water pipe? That's crazy!

Those also look like custom made fuses. It looks like the ratings were probably hand stamped on them. Those are pretty cool, so long as theyre used properly

#124173 - 08/20/06 11:40 PM Re: Oddball Fuses  
mxslick  Offline
Joined: Oct 2004
Posts: 803
Atomic City, ID USA
Don't think that's water pipe, but a metal-encased, mineral powder filled (as insulation) cable. I forget the tradename, but there was a thread about it on here somewhere....

Stupid should be painful.

#124174 - 08/21/06 01:09 AM Re: Oddball Fuses  
Trumpy  Offline

Joined: Jul 2002
Posts: 8,223
SI,New Zealand
Pyrotenax. [Linked Image]

#124175 - 08/21/06 07:16 AM Re: Oddball Fuses  
iwire  Offline
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
In the NEC it is called MI Cable.

It is fireproof (more or less) it can operate even while sections of it are exposed to open flame.

A typical use of it is for life safety emergency circuits.

The insulation between the copper conductor and the copper sheath looks like Sheetrock and is somewhat flexible until exposed to high heat than I believe it turns hard more like ceramic.

Bob Badger
Construction & Maintenance Electrician

#124176 - 08/21/06 03:12 PM Re: Oddball Fuses  
RODALCO  Offline
Joined: Dec 2005
Posts: 854
Titirangi, Akld, New Zealand

Mineral Insulated Metal Sheethed

The product of rotation, excitation and flux produces electricty.

#124177 - 08/21/06 05:43 PM Re: Oddball Fuses  
Rewired  Offline
Joined: Jan 2006
Posts: 558
Hamilton, Ontario, Canada
Just an off the wall question but do you think they used this type of conductor because it basically runs unfused from the service head ( between the 2nd and 3rd floors) down to the sub basement where the disconnect is located... I assume they would have to have buried it in the masonry and concrete slab for protection?!?!
Doesnt seem correct, but thats how it was done 40+ odd years ago.


#124178 - 08/21/06 08:42 PM Re: Oddball Fuses  
Trumpy  Offline

Joined: Jul 2002
Posts: 8,223
SI,New Zealand
Here is the thread where MI (pyro) cable was discussed. [Linked Image]

{Message edited to fix tag}

[This message has been edited by Trumpy (edited 08-21-2006).]

#124179 - 08/21/06 11:27 PM Re: Oddball Fuses  
Rewired  Offline
Joined: Jan 2006
Posts: 558
Hamilton, Ontario, Canada
Very cool! I will be definately looking up more information on pyro cables. That is the first time I have actually seen it installed and in service. Too bad its not too popular here any more, I would have really liked to get lessons on how to properly install pyro and get some hands on experience installing the stuff.


#124180 - 08/22/06 07:32 AM Re: Oddball Fuses  
resqcapt19  Offline
Joined: Nov 2000
Posts: 2,148
It looks like the lock nuts on the MI connectors are ferrous. That could be a problem. It apprears that the 3 MI connectors enter the enclosure via some type of plate that is bolted to the inside of the enclosure. I assume that is nonferrous to pevent induction heating.


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