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#110436 04/10/06 06:52 PM
Joined: Dec 2000
Posts: 4,289
This panelboard powers the lighting in the stairs and corridors, the exit fixtures, etc in a 9 story residential building.

In an outage, the 480V generator will power this panel through a little 30 KVA transformer.

And then..............?

[Linked Image]

[Linked Image]

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#110437 04/10/06 07:05 PM
Joined: Jul 2002
Posts: 8,426
Likes: 3
Well Scott,
That transformer will work.... for a short time at least.
How could a thing like this happen?.
One other thing, I have certain mis-givings about that run of EMT over the top of that exhaust silencer as well, we all know how hot they get!. [Linked Image]

#110438 04/11/06 10:55 PM
Joined: Oct 2004
Posts: 132
What exactly is wrong here...I thought the panel was not fed, but on closer look it seems there is a feeder coming in the bottom of what looks like a feed trhough panel.

Am I missing something stupidly obvious?


#110439 04/12/06 05:44 AM
Joined: May 2001
Posts: 717
Agreed, more info is needed here. Many of those 'silencers' (they're not called mufflers for a reason) are wrapped inside with fire and heat retardent. That means it may not get as hot as you'd think, but that should be in the submittal documents. It also appears that it was here for some time prior to the EMT, so who's problem is that?

I'd be more concerned with the "air over" portion of the cooling. That's something that will get overlooked over the years.

#110440 04/12/06 06:06 AM
Joined: Dec 2004
Posts: 329
"the 480V generator will power this panel through a little 30 KVA transformer.

And then..............?"

While a 30KVA transformer looks a little undersized for the generator. (I am guessing by the 6cyl diesel that it is 60KW or more)
If it has a correctly sized OCD it should be fine electrically. No doubt the diesel will wet stackfrom being underloaded, but that is another story. Outside of the EMT over the exhaust, I don't see too much problem.
Well, I don't see any fire suppression system either, but that could just be outside of the photo.

#110441 04/12/06 07:14 AM
Joined: Feb 2002
Posts: 183
30KVA for 9 stories is about 3KVA/floor. Depending on the size of each floor and types of fixtures on emergency power, that may be enough.

#110442 04/12/06 11:54 AM
Joined: Dec 2004
Posts: 3
Junior Member
Since this is a lighting and appliance panel,408.36(D) requires overcurrent protection on the secondary side of the transformer. I don't see a main breaker or any other OCP device in the picture.

#110443 04/13/06 04:07 AM
Joined: May 2005
Posts: 247
I would assume that the generator is powering more than just lighting, otherwise why would it be a 480v genset?

#110444 04/13/06 06:37 AM
Joined: Dec 2000
Posts: 4,289
Sorry it took me so long to get back to this.

The 30 KVA is plenty to supply the loads that are fed here. My big concern is with the 1" EMT run right above the silencer.

This is not the original panel that was installed, it was installed, I believe, after this one about 10' away burnt out, . (And probably without a permit or inspection)

[Linked Image]

There's lots of heat coming off of that exhaust system. This has happened just during weekly tests of about 15 minutes.

[Linked Image]

Also, the panel is mounted right under the silencer's drain plug.

The 480V genset does supply other loads, but has enough capacity to handle them.

#110445 05/02/06 05:09 PM
Joined: Aug 2005
Posts: 24
9 story building? 480v generator?

Can you say "elevator machinery"

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