Commercial mini breaker

[DanZ]

Hey guys, I've got an odd question for you.

I'm currently working on a dentist office remodel, and when I looked at the existing panel, it had several "mini" breakers, in both a side by side (half size) and straight across versions. I should have taken pictures of the breakers, but unfortunately, I didn't.

It's a B Use group (commercial) office, with a single phase 200A service and an existing Square D QOC42U 42 space panel. There are currently 31 breakers on the odd numbered side of the panel and 28 on the even numbered side. If it's allowed, I would like to reuse the existing breakers to do new the new work, since we're lessening the number of receptacles in the treatment rooms, as well as the number of treatment rooms.

This job is in Ohio, so it would be under the 2008 NEC, I believe.

Does anyone have a code section they can reference, or a cut sheet for the panel that says we can or can't use these mini breakers?

Thanks,
Dan

 

[Buck Parrish]

I don't have a reference. But the number of breakers has been lifted in 08.
I am not sure if that applies to Commercial I am pretty sre that it does.
Those SQ. D mini side by side breakers do look kind of weird. But they should be listed for that application.
Did you look on the panel cove for breakers allowed?
I don't see a problem with it. As long as the load is below the Max. ampacity of the panel.

 

[DanZ]

I know the max number has been lifted from 42, but it's pretty much (to my understanding) been lifted to whatever the Manufacturer sees as safe. From what I can tell, anything using the Square D QOC42U number is listed at 42 circuits max. I did not look for max breakers on the tags, I should have. It's a single phase (200A), and overloaded with breakers (59 in the panel), with a sub panel (4 of the 20 mini breakers in the main panel) with 4 20A breakers, with a sub panel coming off that, that has a combo or 30-60 breakers for the washer/dryer, range, and something else. I'm seriously thinking it should all be torn out and redone with a service upgrade, but I really don't see my boss going for that.

 

[celtic]

It's a B Use group (commercial) office, with a single phase 200A service and an existing Square D QOC42U 42 space panel. There are currently 31 breakers on the odd numbered side of the panel and 28 on the even numbered side.
This job is in Ohio, so it would be under the 2008 NEC, I believe.

Being under the '08 would not automatically cause the panel to allowed to have in excess of 42 CBs

From what I can tell, anything using the Square D QOC42U number is listed at 42 circuits max. I did not look for max breakers on the tags, I should have. It's a single phase (200A), and overloaded with breakers (59 in the panel),

The "42" in the model number *MAY* be an indication of the max number of spaces/poles available..however, the number you provided is the cover catalog number (see pg.6 in below link)..it might also be for a 40 ckt. panel (QO140M200)
http://www.squared.com/us/products/gendoc.nsf/bce2f96988bd1a338625643a006e3b29/32c922ae0df4918d85256f6c005e8b6c/$FILE/0100EP0702.pdf
(in .pdf format)

I'm thinking it's a 42ckt panel based on your 200A limitation....had it been a 225A it could have gone either way (QO140M225 or QO142M225).

Does anyone have a code section they can reference, or a cut sheet for the panel that says we can or can't use these mini breakers?

*ASSUMING* this panel is a QO142M200 (42ckt/200A/1?).....

Features and Specifications

Approvals: UL Listed
Ampere Rating: 200A
Application: Designed to meet residential, commercial and industrial requirements to protect electrical systems, equipment and people.
Cover Type: Order separately
Grounding Bar: Order separately
Bus Material: Tin Plated Copper
Main Type: Convertible - Factory installed main breaker
Catalog Reference Number: 1100CT9901
Maximum Single Pole Circuits: 42
Short Circuit Current Rating: 22kA
Enclosure Type: Indoor
Enclosure Rating: NEMA 1
Maximum Tandem Circuit Breakers: 0
Depth: 3.75 Inches
Height: 37.98 Inches
Spaces: 42
Wiring Configuration: 3-Wire
Phase: 1-Phase
Voltage Rating: 120/240VAC
Wire Size: #4 to 300 AWG/kcmil(Al/Cu)
Width: 14.25 Inches

...on the other hand, I could be completely wrong in which case disregard all this nonsense

 

[DanZ]

The "42" in the model number *MAY* be an indication of the max number of spaces/poles available..however, the number you provided is the cover catalog number (see pg.6 in below link)..it might also be for a 40 ckt. panel (QO140M200)
http://www.squared.com/us/products/gendoc.nsf/bce2f96988bd1a338625643a006e3b29/32c922ae0df4918d85256f6c005e8b6c/$FILE/0100EP0702.pdf
(in .pdf format)

I just found that out. There was space for 42 full size breakers in the panel, and they were all being used!

I'm thinking it's a 42ckt panel based on your 200A limitation....had it been a 225A it could have gone either way (QO140M225 or QO142M225).

It didn't have a main in the panel, it was in a disconnect on the side of the building, but I'm still guessing it's rated or listed for 42 circuits max.

*ASSUMING* this panel is a QO142M200 (42ckt/200A/1?).....

...on the other hand, I could be completely wrong in which case disregard all this nonsense

That might be it! It looked like a big gray box, flush mounted in the wall...:roll:

 

[SEO]

I agree with celtic . Look a section 408.54. They probably used tandem breakers that are stamped for replacement use only.

 

[jim dungar]

Your panel is not rated for tandem breakers. As it has been said the catalog number you gave is for a cover that has 42 breaker knockout locations. Square D has never built any panel, that uses that cover, that is listed for tandem breakers.

 

[celtic]

It didn't have a main in the panel, it was in a disconnect on the side of the building...

The panel would have a L for lugs in the model number instead of an M

 

[DanZ]

I agree with celtic . Look a section 408.54. They probably used tandem breakers that are stamped for replacement use only.

Or something that doesn't fit right, or was modified slightly...:roll:

Your panel is not rated for tandem breakers. As it has been said the catalog number you gave is for a cover that has 42 breaker knockout locations. Square D has never built any panel, that uses that cover, that is listed for tandem breakers.

That's what I figured. Looks like we'll have to run a sub panel and move a bunch of stuff, or tear it all out and re do a whole bunch of stuff. Or, submit drawings as it is, and "hope" they don't catch it...to appease my boss, and keep the sub panel and tear out ideas in my back pocket. :grin:

 

[DanZ]

The panel would have a L for lugs in the model number instead of an M

??? It had the space for a main, but it hadn't been punched through. You only need one main OCPD, and I think local code requires one on the exterior of commercial buildings, so fire departments...or kids having fun...can turn the power off from outside.

 

[celtic]

??? It had the space for a main, but it hadn't been punched through.

The covers are rather generic...a lug only and main being the same cover....difference being the ko being used or not.

Regardless of that....

...from what you have told us, and what we have discovered, it seems there is an issue that needs addressing.
Hopefully, your boss will understand this and can translate it to the customer.

 

[DanZ]

...from what you have told us, and what we have discovered, it seems there is an issue that needs addressing.
Hopefully, your boss will understand this and can translate it to the customer.

That's what I'm hoping. It may come down to my boss having me leave it "as is" with our changes, and taking the correction letter to the customer and telling them we can't do it.

Part of me wants to establish a good reputation with the AHJ and the people of the various building departments, while the other part of me wants to keep the guy who signs my pay check happy...:roll:

 

[C3PO]

I agree with Jim and Celtic. With a QOC42 cover you have at most 42 spaces (it is probablly a QO142L225G) with none of the spaces listed for use with tandem breakers. What they have probablly done is use a QO2020 or QO1515 tandem in the panel. They will snap in the panel in any location but they are not listed for use in a CTL panelboard.

I see a lot of "electricians" use these these breakers anyway. When you tell them they are not for CTL panels they look at you wierd and say what is a CTL panelboard.

 

[DanZ]

I agree with Jim and Celtic. With a QOC42 cover you have at most 42 spaces (it is probablly a QO142L225G) with none of the spaces listed for use with tandem breakers. What they have probablly done is use a QO2020 or QO1515 tandem in the panel. They will snap in the panel in any location but they are not listed for use in a CTL panelboard.

That's pretty much what I figured. Hey, it fits, right?!?:grin:

I see a lot of "electricians" use these these breakers anyway. When you tell them they are not for CTL panels they look at you wierd and say what is a CTL panelboard.

Uhm...what is a CTL panelboard?
I'm not an electrician, I'm just the designer/drafter/Architect without a stamp...:grin:

 

[DanZ]

Well, I talked to my boss, and he thinks it would be a good idea to send our EC over there to see what his take is. I'm pretty sure he's going to want to replace it, or run a sub panel and move a bunch of stuff. :grin: :grin: :grin:

I still can't believe how many times I've heard "It's existing..." about this job.:roll:

 

[C3PO]

That's pretty much what I figured. Hey, it fits, right?!?:grin:
Uhm...what is a CTL panelboard?
I'm not an electrician, I'm just the designer/drafter/Architect without a stamp...:grin:

I can't remeber when panelboards started being listed CTL but has been a long time. (20-30 years)

CLASS CTL PANELBOARDS
Circuit-limiting panelboards (known as "Class CTL" panelboards) are identified by the words "Class CTL" on the UL Listing Mark.
Class CTL panelboards incorporate physical features which, in conjunction with the physical size, configuration, or other means provided in Class CTL circuit breakers, fuseholders or fusible switches, are designed to prevent the installation of more overcurrent protective poles than that number for which the device is designed and rated.

 

[jim dungar]

I can't remeber when panelboards started being listed CTL but has been a long time. (20-30 years)

It is more like 40-45 years.

 

[C3PO]

It is more like 40-45 years.

I couldn't remember for sure I was just guessing on that part. :smile:

 

[norcal]

I can't remeber when panelboards started being listed CTL but has been a long time. (20-30 years)

If I remember correctly, catalogs used to list Non-CTL twin breakers as being manufactured for panels built prior to 1968.

 

[jim dungar]

If I remember correctly, catalogs used to list Non-CTL twin breakers as being manufactured for panels built prior to 1968.

But even then, the panel had to be rated for use with tandems. Just because they fit, didn't mean you could use them.