84-pole panelboards, pros vs cons?

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I used a 84 recently. Originally the job called for a two section but I didn't have the room. Fortunatly I had 30 circuits coming in the bottom. I wouldn't want to bring 84 circuits in the top. I used mostly MWBCs in the top and it worked out good. Ended up with 73 circuits and 11 spares. There is a picture of it right after it was mounted on the wall in another thread.
 
Steviechia2 said:
It really comes down to the load. I just did a job where we had several 84 circuit panels, it was just 2-42 circuit Square D main lug panel-boards nippled together with numbers 1-84. One fed the other
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I think you're missing the point. The topic is about 1 panel with 84 circuits. Yeah, it's essentially the same thing but in one package.

I think I would only use one if space was a big factor, or if it was much cheaper. I could see it getting very crowded. Someone mentioned using multiwire circuits to cut down on wires, but we don't use many mwbc's with the latest code change. I think residential is the best application for a panel that size.
 
Are the 84-pole panelboards not wide enough to accommodate 84 branch circuits? How is the width with other panelboards, such as 54-pole, 60-pole, or 72-pole? Are the heights of these panels significantly taller than the 42-pole? Can this be a problem, too?
 
One more question. Would the use of an 84-pole panelboard make sense in an application in which many 3-phase circuits are involved?
 
AQC said:
The NEC 2008 allows use for panelboards up to 84-poles. Please help me understand any advantages and/or disadvantages to using panelboards greater than 42-poles. Has anybody here used panelboards that are 84-poles (or 54, or 60, or 72, etc etc), and what is your experience with them?

Thanks,
AQC
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Where is the section in the NEC that limits panelboards to 84 poles?
 
AQC said:
For clarification, I'm thinking more in terms of commercial/retail panelboard installation as opposed to residential installation.

Continue the answers, they are good so far!
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I've installed several of them in the last year--Square D NQ series, 84 circuits.
We do a lot of data center/computer room type jobs, and these really save on wall space. We like the first panel coming from the UPS to have a 3P MCB of the MC (mission critical) type, guaranteeing that a short on the downstream side of 1P 20A thru 3P 30A branch cb will not trip the main. The "MC" CB is expensive, so for about 8 years we order that with TFL for the first panel and then sub feed lugs for downstream panels, all protected by the "MC" main cb. I've got multiple installations of 4-5 Panelboards (168 to 210 circuits) subfed one to another. With the (Yes--very tall, like 80") 84 circuit panelboards I can get 3 x 84 = 252 circuits in a little over 60" of wall space. That used to take 120+" with the 42 circuit rule.
 
CFL said:
I think you're missing the point. The topic is about 1 panel with 84 circuits. Yeah, it's essentially the same thing but in one package.

I think I would only use one if space was a big factor, or if it was much cheaper. I could see it getting very crowded. Someone mentioned using multiwire circuits to cut down on wires, but we don't use many mwbc's with the latest code change. I think residential is the best application for a panel that size.
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We run multiple 1-1/4" EMT down under the floor, less than 24" long, to large (18x18x6) home run pull boxes. Since most of our circuits are 1-phase 1 neutral and 1 IG ground wire, we have ended up with as many as 252 wires (most #12, some #10) in the panels, all loads exiting down. Pretty crowded but if it's done really neatly (and we use wire markers on all 3 conductors per circuit to facilitate future removal/rewiring), it comes out very good looking.
Since the panels are so tall, you could also put the (Max. 23.5") EMT sleeve up thru a T-bar ceiling at 9 feet, for overhead load circuit.

One other plus--when pulling in future branch circuits, you are pulling into the large j-box, not into the panel with hot busses, then push the last 24" up into the panelboard. Jobs like this have all the later adds done energized.:)
 
In residential it always seems to make more sense to stick a sub panel somewhere that helps with homeruns and future addition, second floor laundry rooms tend to be the preferred spot for us.
 
NEC allows 42 cir per panel. I have installed many 84 circuit panels they are (2) 42 circuit panels side by side. The feeder supplys power to the first then there are lugs that feed through to the other panel. They are very large cans 72" plus (depending on voltage and the panel Amps and if you have a main installed or not) I have had problems installing these panels in some situations where I have Class 1 Div 2 areas and have to keep the panel above 18". The problem comes from having to keep within the NEC rule for the hight of a breaker AFF.

The width of the panels are still 20" (i use Cutler HAmmer/GE)

Every application that I use the panels are 3 ph 4 wire. The only problem is it would be impossible to install a 3 pole breaker on circuits 42,44,46. You would have to check to make sure there are no multiple pole breakers that are engineered between 41,43 or 42,44

also make sure that if the panels are to be installed in a flush panel installation that you give yourself enuff room for the covers.
 
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