Need MI Cable

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iwire

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Massachusetts
Do you mean to say the the room - where the pictures are taken - is NOT fire rated but travel through the ceilings of the hospital to other rooms that ARE fire rated? If that is the case it would have been more cost effective to make the conversion AT the fire rating boundary. Just wondering what type of fire rated equipment would supply the panel feeders.

No I meant what I said, this room is supplied at 13.8 kV by protected feeders and from this fire rated room it is distributed to other fire rated rooms.

Do you not notice the block walls and the extensive use of fire stop?
 
No I meant what I said, this room is supplied at 13.8 kV by protected feeders and from this fire rated room it is distributed to other fire rated rooms.

Do you not notice the block walls and the extensive use of fire stop?

Noticed it and I think I got it. So the MI cables are only necessary when they leave the room and travel through areas where fire is expected/allowed to occur, and the EMTs are used for interconnection within the fire rated room.
 

iwire

Moderator
Staff member
Location
Massachusetts
Noticed it and I think I got it. So the MI cables are only necessary when they leave the room and travel through areas where fire is expected/allowed to occur, and the EMTs are used for interconnection within the fire rated room.


Where fire is allowed or expected?:D

Very odd way to put it but yes, building furnishings can catch on fire even in fire rated construction.
 
Where fire is allowed or expected?:D

Very odd way to put it but yes, building furnishings can catch on fire even in fire rated construction.

That is exactly where it gets confusing. If the intent of the fire rated electrical room is to prevent the propagation of the fire that originated in the electrical room, then the MI cables would have no useful purpose (within)in the room and a simple transit at the fire break point from normal wiring to MI cable would be sufficient. The question is/was the intent of the design; was the fire intended to be kept out of the room, or is the design aimed at containing the fire within the room?
 

iwire

Moderator
Staff member
Location
Massachusetts
I believe the intent is to make sure the electrical distribution gear is protected from a fire.

You don't want a fire in say, a public hallway to melt out the emergency feeders above that ceiling as they travel from one electrical room to another.

MA has additional requirements about emergency distribution gear that require the emergency gear is not in the same room as the normal gear.

About 20+ years ago here in Boston a new large hotel had an electrical fire in the main electrical room. That same room housed the fire alarm control panel and the emergency distribution equipment. The fire in the normal gear took out the emergency system and fire alarm systems, putting the entire building in the dark even though the fire was contained to one room.
 

Riograndeelectric

Senior Member
I am very impressed with the workmanship and installation of the MI cable in the pictures.
I have to say the person or person installing the MI cable took there time in making the installation look extremely neat.

so you allowed to run MI cable as Parell conductors?

what is the fire rating of MI cable?

I wire do you know how many hours theirs job took for just the electrical room?
 

cowboyjwc

Moderator
Staff member
Location
Simi Valley, CA
that's interesting. i've never worked with it, nor seen an install
in person on the left coast... i've seen references to MI cable installs in the
NEC, and thought it was something grandfathered in...

and yeah, looking at the install, i don't want to think how much of a pain
putting that in and making it look nice would amount to.

I'm right there with you.
 

iwire

Moderator
Staff member
Location
Massachusetts
I am very impressed with the workmanship and installation of the MI cable in the pictures.

So am I.


so you allowed to run MI cable as Parell conductors?

Yes, but there are none here, each group of four is A, B, C, & N, the outer sheath is the EGC.

what is the fire rating of MI cable?

I think it is 2 hours but I am not sure.

I wire do you know how many hours theirs job took for just the electrical room?

No I do not, I was there doing some other work shortly after the MI was installed.
 

iwire

Moderator
Staff member
Location
Massachusetts
and yeah, looking at the install, i don't want to think how much of a pain
putting that in and making it look nice would amount to.

My pictures do not show more than 5% of it if that. The feeders leave this room and run 100s of feet above crowded suspended ceilings and up or down to other floors without any splices. It must of taken a lot of guys and a lot of work. My hats off to them.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
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