300.20(b)....

Status
Not open for further replies.
C

chevyx92

Senior Member
Location
VA BCH, VA
Can someone please explain this article and give and example of a practical situation where you need to do this? Cutting slots, huh?? :confused:
 
chevyx92 said:
Can someone please explain this article and give and example of a practical situation where you need to do this? Cutting slots, huh?? :confused:
Click to expand...
Parallel feeders into a steel exterior main building disconnect switch. They line up nicely to the lugs while you are scratching your head wondering what a nice installation I wonder why the paint around the locknuts is all discolored and corroded?? After you replace the fuses and you are driving home in the van the lightbulb goes off in your head!!!!!!!! The boss says just put in bigger fuses hey you gotta laugh. The locknuts still complete the path unless you dont tighten them enough to break the paint.
 
Here is an example of single conductor MI cable.

MICable01.jpg


We are looking at three - 3 phase, 4 wire feeders coming out of an emergency (or would it be life safety?) distribution panel in a hospital.

The installers here cut out the steel and installed non-ferris metal to enter the conductors but the NEC would allow just cutting slots between the four KOs of each feeder.
 
iwire said:
Here is an example of single conductor MI cable.

MICable01.jpg


We are looking at three - 3 phase, 4 wire feeders coming out of an emergency (or would it be life safety?) distribution panel in a hospital.

The installers here cut out the steel and installed non-ferris metal to enter the conductors but the NEC would allow just cutting slots between the four KOs of each feeder.
Click to expand...

Nice pic. I haven't used MI cable before. Is that copper jacket with a single copper conductor in each piece of cable there?
 
chevyx92 said:
Is that copper jacket with a single copper conductor in each piece of cable there?
Click to expand...

Yes, the conductor is insulated from the copper sheath by a mineral that looks like gypsum.

It is a major pain to work with but will keep working even if directly exposed to fire.
 
Dennis Alwon said:
And what good is that if the feeder is in emt? :grin:
Click to expand...

That EMT is not supplying the panel, I don't recall what it does. It was not my work, I was there doing other work. :)
 
iwire said:
Yes, the conductor is insulated from the copper sheath by a mineral that looks like gypsum.

It is a major pain to work with but will keep working even if directly exposed to fire.
Click to expand...


That's what my house is wired with. Can't take a risk with that deadly romex....:grin:
 
iwire said:
Here is an example of single conductor MI cable.

MICable01.jpg


We are looking at three - 3 phase, 4 wire feeders coming out of an emergency (or would it be life safety?) distribution panel in a hospital.

The installers here cut out the steel and installed non-ferris metal to enter the conductors but the NEC would allow just cutting slots between the four KOs of each feeder.
Click to expand...
Wow, that seems like a major PIA to install, big coordination of trades thing... clearly the plumber goes first to put in the tubing, but who goes next, the drywall guy or the electrician :grin: :grin: :grin:
 
Status
Not open for further replies.
Top