more than 42 breakers in a panel with AFCI

Don't get too excited. As noted in the discussion, UL limitations still exist. I believe UL limits 100A panels to 20 poles (at least single phase), 40 in a 200A panel. These are class CTL (ciruit limiting).

bud--

| snipped-for-privacy@ipal.net wrote: |> It looks like we will be able to have more than 42 breakers in a panel |> come 2008, depending on local adoption. NEC 408.35 is going away if |> things proceed as they seem. That would be a good thing with panels |> being stuff full of AFCI breakers. Now they can be spaced apart in |> larger panels (though you might not want to space them at every other |> position unless you at least put them at the other positions on the |> other side). |> |> So how big will braker panels get? I see they have them as large as |> 84 slots in Canada, so I presume we could see those showing up here |> around 2008. |> | Don't get too excited. As noted in the discussion, UL limitations still | exist. I believe UL limits 100A panels to 20 poles (at least single | phase), 40 in a 200A panel. These are class CTL (ciruit limiting).

UL rules are like CSA rules, and CSA allows 200 amp panels up to at least

84 circuits. They are larger panels; this isn't being achieved with a lot of tandems. I'd bet the UL rules are based on the box size, and with the right space,more slots would be OK. What we probably have to wait for is the formalized testing of the new larger boxes.

Alternatively, manufacturers _may_ make boxes that are intentially spaced out larger, with gaps in the otherwise solid stack of breakers, to give heat dissipation room to the AFCI breakers. That's the way I would put them in a panel, anyway: get an 84 slot panel and put them in like:

AFCI-*-|-AFCI AFCI-|-*-AFCI -*-|- AFCI-|-*-AFCI AFCI-*-|-AFCI -|-*- AFCI-*-|-AFCI AFCI-|-*-AFCI -*-|- AFCI-|-*-AFCI AFCI-*-|-AFCI -|-*- AFCI-*-|-AFCI AFCI-|-*-AFCI -*-|- AFCI-|-*-AFCI AFCI-*-|-AFCI -|-*- AFCI-*-|-AFCI AFCI-|-*-AFCI -*-|- AFCI-|-*-AFCI AFCI-*-|-AFCI -|-*- AFCI-*-|-AFCI AFCI-|-*-AFCI -*-|- AFCI-|-*-AFCI AFCI-*-|-AFCI -|-*- AFCI-*-|-AFCI AFCI-|-*-AFCI -*-|- AFCI-|-*-AFCI AFCI-*-|-AFCI -|-*- AFCI-*-|-AFCI AFCI-|-*-AFCI -*-|- AFCI-|-*-AFCI AFCI-*-|-AFCI -|-*-

U/L will do whatever the manufacurer's tell them to do. They manufacturer can submit a 200 slot panel and U/L will test it and if it doesn't burst into flames they will list it. Whether an AHJ actually accepts it is up to the AHJ as guided by NFPA, NEMA or their local union rep.

The NEC currently allows single phase residential panels with 42 poles. Does anyone make a 100A panel that allows installation of more than 20 poles? Or more than 40 poles in a 200A panel? Far as I know the UL standard does not permit it.

bud--

On Sun, 08 Oct 2006 20:27:27 -0400 snipped-for-privacy@aol.com wrote: | On 8 Oct 2006 17:52:49 GMT, snipped-for-privacy@ipal.net wrote: | |> I'd bet the UL rules are based on the box size, and with |>the right space,more slots would be OK. What we probably have to wait |>for is the formalized testing of the new larger boxes. | U/L will do whatever the manufacurer's tell them to do. | They manufacturer can submit a 200 slot panel and U/L will test it and | if it doesn't burst into flames they will list it. | Whether an AHJ actually accepts it is up to the AHJ as guided by NFPA, | NEMA or their local union rep.

How often do they burst into flames? I'm just curious how fun of a job it is at the UL testing facilities. :-)

In Canada, Square-D already sells (under the Schneider name), NF series panels with 54 and 66 spaces, and NQOD series panels with 54, 72, and 84 spaces. The QO series has a 60 space panel, as well as a 40 space panel that is rated for 64 poles (presumably using 24 tandems and 16 full size breakers). Maybe they will take these same designs and submit them to UL for testing to get listed in the US (if not already) and start selling them in areas where NEC 2008 gets adopted. I looked for larger Canadian panels from Eaton Cutler-Hammer, but could not find any.

On Mon, 09 Oct 2006 02:24:05 -0500 Bud-- wrote: | snipped-for-privacy@aol.com wrote: |> On 8 Oct 2006 17:52:49 GMT, snipped-for-privacy@ipal.net wrote: |> |> |>> I'd bet the UL rules are based on the box size, and with |>>the right space,more slots would be OK. What we probably have to wait |>>for is the formalized testing of the new larger boxes. |> |> U/L will do whatever the manufacurer's tell them to do. |> They manufacturer can submit a 200 slot panel and U/L will test it and |> if it doesn't burst into flames they will list it. |> Whether an AHJ actually accepts it is up to the AHJ as guided by NFPA, |> NEMA or their local union rep. | | The NEC currently allows single phase residential panels with 42 poles. | Does anyone make a 100A panel that allows installation of more than 20 | poles? Or more than 40 poles in a 200A panel? Far as I know the UL | standard does not permit it.

Eaton Cutler-Hammer has listed in their catalog, CH series panels that have up to 30 spaces for 100 or 125 amp, 32 spaces for 150 amp, 42 spaces for 200, 225, 300, or 400 amp. These are main breaker panels. Main lug panels only go up to 24 spaces for 125 amp, 32 spaces for 150 amp, 16 spaces for 200 amp (probably just an odd bus here), and 42 spaces for

225 amp. I suspect some of the lower amperage MCB panels really have larger busses but with mountings for smaller main breakers.

Square-D has similar, but I did notice a 100 amp MCB panel up to 32 spaces in the QO series.

I did not look at BR or HOM series, or other brands like GE or Siemens.

Do you have a copy of the UL standard that limits 200 amp panels to no more than 40 poles?

I have a 40 branch circuit 200a panel, but then the main disconnect counts as two. So 42 here.

later,

tom @

On Mon, 09 Oct 2006 08:02:31 -0400 Tom The Great wrote: | On Mon, 09 Oct 2006 02:24:05 -0500, Bud-- | wrote: | |> snipped-for-privacy@aol.com wrote: |>> On 8 Oct 2006 17:52:49 GMT, snipped-for-privacy@ipal.net wrote: |>> |>> |>>> I'd bet the UL rules are based on the box size, and with |>>>the right space,more slots would be OK. What we probably have to wait |>>>for is the formalized testing of the new larger boxes. |>> |>> U/L will do whatever the manufacurer's tell them to do. |>> They manufacturer can submit a 200 slot panel and U/L will test it and |>> if it doesn't burst into flames they will list it. |>> Whether an AHJ actually accepts it is up to the AHJ as guided by NFPA, |>> NEMA or their local union rep. |>

|>The NEC currently allows single phase residential panels with 42 poles. |>Does anyone make a 100A panel that allows installation of more than 20 |>poles? Or more than 40 poles in a 200A panel? Far as I know the UL |>standard does not permit it. |>

|>bud-- | | | I have a 40 branch circuit 200a panel, but then the main disconnect | counts as two. So 42 here.

The rule that limits the panel to 42 poles does not count the main.

Yup, looks like CH has panels over my 30/40 limit.

I had thought my old SqD catalog didn't have poles above a 20/40 limit, but there were somer even in that old catalog that were over. I was wrong about the UL limit.

Nope. Sure would be nice if the UL standards, or a good summary, were available online.

-------------- The commentary in the ROP says the 42 pole limit also appears in the UL panelboard standard, so you will have to wait for bigger panels until the UL standard is changed.

bud--

| Nope. Sure would be nice if the UL standards, or a good summary, were | available online.

Best they have is an index. It would be nice to know what they test for so the public understands the value of the mark. But alas, most of the public is essentially a zombie in this regard.