The "instructions" that appear here are required to be followed in order to show compliance with 110.2, otherwise the job gets Red Tagged.

Ahh Darryl, give the guy break! I mean, the panel's not even full yet--he's still got three more spaces at the bottom of the panel.


With work like this, the guy must be Canadian or something...

[This message has been edited by SolarPowered (edited 07-22-2005).]

Help me out here, please. Am I missing something in the panel instructions that limits the number of OCDs?

It seems to me that anybody who installs a separate branch circuit for the "blender" (#37) is being pretty conscientious.

John,

In big letters, up at the top: G4040ML1200CU. And in the lower corner, Class CTL. Those first few numbers and letters say it has 40 spaces, in which 40 poles are permitted. Class CTL means that it's designed to reject Class CTL tandems, which means that they've either modified the panel to take the tandems, or they're using non-Class CTL breakers.

Also, assuming that this is a "Lighting and Small Appliance Panelboard", the absolute maximum number of poles permitted under the NEC is 42.

Solar, thanks for the explanation. I gather that all lighting & appliance panelboards have "4040" (or other) as part of their catalog numbers, so the problem was obvious to everyone but me

Thanks to your pointer about the "CTL" class designation, I found a page that explained the history nicely:
http://www.mikeholt.com/misc.php?id=unformatted/8-29-99&type=u&title=Circuit+Breakers+-+CTL+Assemblies+(8/29/99)

So, I understand now that this is probably a case of using CBs marked "Replacement Use Only - Not for CTL assemblies" in a CTL panelboard.

This is a perfect example of why I lurk here -- I learn something nearly every day.

(Note to "Hitchikers Guide to the Galaxy" fans: Now we know what the ultimate question is!)

So they corrected their violation and you still are not passing their work. Ugh.

John, I don't know whether ALL panelboards use the "4040" nomenclature--as far as I know, there's no provision in the code that requires that. Rather, it's common enough that you can pretty much figure out what the panel is from the number.

There should be a specific mention on the instructions about what is allowed, and what isn't. It may be in the directory part (where "blender" is written in). The diagram in the middle shows only one pole in each position; if a tandem is allowed, the diagram normally shows two poles. I'm thinking that there's some sort of note printed just above the directory that doesn't show in the pictures.

electricmanscott:
I wouldn't consider reducing the number to 54 exactly 'correcting the problem'. Plus the issue if the breakers are listed for use in the panel. If I was inspecting, I think I'd want to see some load calcs before I signed off on something like that.

SolarPowered
"...With work like this, the guy must be Canadian or something..."

No we would at least use Robertson screws to hold the cover on. :=)

Besides what's the big deal how many breakers you have in a panel? As long as the bus is rated for the current that the Over current protection will allow through I see no safety issue.
If we had that code over here we would be putting subpanels in New Houses. It looks a lot neater with one nice size 84 circuit panel on the wall than 2 - 42 circuit panels

Dynamite, I agree with you that the 42 circuit limit seems arbitrary- and should be deleted.

I believe the number of circuits in a panel is a design issue. Personally, I prefer a main panel serving a galaxy of satellite sub-panels.
I prefer multiple subs for two reasons: the breaker should be located close to the area it serves, and there is a limited number of openings you can put in a panel case.
Using your example, 84 romex circuits would need at least 42 1/2" knockouts- under the best of circumstances, 21 top and 21 bottom. That many holes needs a lot of metal!

Reno, let's not forget that sub-panels can mean more efficient distribution of power, as a feeder can have less voltage drop than several branch circuits running the same distance, because of load diversity.

I guess my comment about "the guy must be Canadian or something..." was a bit too subtle. I was referring to the fact (as DYNAMITE mentions) that there is no 42-pole rule in Canada, and they have panels that go up to at least 84 poles, and perhaps more. I'm sure our Canadian brothers do work that is very comparable in quality to that done south of the Canadian border.

[This message has been edited by SolarPowered (edited 10-11-2005).]

Eh?

As Joe points out in another thread, now is the time to submit proposals for the next NEC edition.
Has anyone suggested eliminating the "42 rule" as arbitrary?

Er, eliminate the rule? They should make it less!! Thank god I rarely do residential, but could you imagine a residential box with 84 breakers! What a rats nest of wires that would be.

Using your example, 84 romex circuits would need at least 42 1/2" knockouts- under the best of circumstances, 21 top and 21 bottom.

Not around here! All new residential construction I've seen in this area has all homeruns crammed into a single chase nipple, PVC MA, or clamp connector, usually 2.5"!

Yatix. apologise...silly me, thinking anyone actually paid attention to the code, listing requirements, or strain relief! :-)

Yatix. apologise...silly me, thinking anyone actually paid attention to the code, listing requirements, or strain relief! :-)

Well, some of us do, but we can't change the world...