Siemens panels numbers of spaces & circuits

[RustyShackleford]

This may be an issue for other panel manufacturers, but I'm familiar with Siemens ...

They rate their panels according to the number of "spaces" and the number of "circuits". If we look at the catalog of available panels in their "plug-on neutral" PN series ...

... we see that the number of circuits can be equal to the number of spaces, or double the number of spaces (fully populated with "space-saver" breakers) or somewhere in between.

I'm just curious why this variation. If the busbars' current-handling capability matches the main breaker, what does it matter how many circuits are connected to the busbars ? Put another way, what is the difference between the 40-40 (spaces-circuits) panel and the 40-60 one ? Both have 200 amp main breakers and presumably busbars to match. Space-saver breakers definitely will work in the 40-40 is panel. Can it simply be the number of ground and neutral bar screws supplied ?

 

[infinity]

Can it simply be the number of ground and neutral bar screws supplied ?

My guess is that it has something to do with this but who knows. I recently did a service upgrade with an 200 amp Eaton plug-on neutral, 40/80 panel and the neutral bar only had 60 spaces. Since there were no AFCI's I had to add an EGC bus on each side.

 

[Fred B]

Space-saver breakers definitely will work in the 40-40 is panel.

No they won't, in the 40-40 the entire bus is limited with rejection and won't allow tandem breakers to attach. There are some that have "modified" the breakers, (not smart) and not code compliant, to get in more than the panel is designed for.

Can it simply be the number of ground and neutral bar screws supplied ?

This is definitely the case, particularly with the PON panels. The neutral bar connection is the concern when "overloading" (more devices than designed for), every Siemens panel I've installed do allow for adding EG bus.

Not sure if this has any factor in the design of these panels but Siemens is the only company that is providing a tandem AFCI breaker

 

[infinity]

No they won't, in the 40-40 the entire bus is limited with rejection and won't allow tandem breakers to attach. There are some that have "modified" the breakers, (not smart) and not code compliant, to get in more than the panel is designed for.

A 40/40 panel is limited to 40 circuits but with Eaton panels like the 40/80 I mentioned prior you can use non-CTL breakers in every slot.

 

[ramsy]

what does it matter how many circuits are connected to the busbars ?

As long as any AHJ still adopts the 2005 NFPA-70 408.35, manufactures will keep building it with that 42 circuit limit, and selling it everywhere that doesn't require it anymore.

42 Circuit Rule in Electrical Panels (PanelBoards/Load Centers), Wenatchee Home Inspections | NCW Home Inspections, LLC

42 Circuit Rule in Electrical Panels (PanelBoards/Load Centers). Wenatchee Home Inspections This subject of how many “Circuits” are allowed in residential electrical panels has come up in a recent discussion. I have had this exact

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[VirutalElectrician]

As long as any AHJ still adopts the 2005 NFPA-70 408.35, manufactures will keep building it with that 42 circuit limit, and selling it everywhere that doesn't require it anymore.

42 Circuit Rule in Electrical Panels (PanelBoards/Load Centers), Wenatchee Home Inspections | NCW Home Inspections, LLC

42 Circuit Rule in Electrical Panels (PanelBoards/Load Centers). Wenatchee Home Inspections This subject of how many “Circuits” are allowed in residential electrical panels has come up in a recent discussion. I have had this exact

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Thank you for the education.
Any data as to what areas are still limited to 42 spaces?

I was surprised when SPAN came out with there panel so small at 32 spaces.

Leviton has 20,30,42, and 66.

 

[RustyShackleford]

No they won't, in the 40-40 the entire bus is limited with rejection and won't allow tandem breakers to attach. There are some that have "modified" the breakers, (not smart) and not code compliant, to get in more than the panel is designed for.

I'm working on a house that has a Siemens 40-40 panel (and older family, I think model# is G4040B1200) and there are a couple of space-saver (by that I mean their QT series) breakers in it. But looking at the door label (online), QT is not listed as an allowable breaker. I better check for modifications.

 

[Fred B]

A 40/40 panel is limited to 40 circuits but with Eaton panels like the 40/80 I mentioned prior you can use non-CTL breakers in every slot.

Depending on listing of panel. yes a 40-80 can be fully populated with tandems but a 40-40 not. Non-CTL are limited to use in older (pre 1968) panels.

I'm working on a house that has a Siemens 40-40 panel (and older family, I think model# is G4040B1200) and there are a couple of space-saver (by that I mean their QT series) breakers in it. But looking at the door label (online), QT is not listed as an allowable breaker. I better check for modifications.

Check panel label, If panel doesn't list a QT type breaker then the tandem wouldn't be allowed per mfg.

 

[ramsy]

Any data as to what areas are still limited to 42 spaces?

Not aware if any jurisdictions still adopt 2005 NFPA-70 408.35, but some still use the 2008 version.

 

[infinity]

Depending on listing of panel. yes a 40-80 can be fully populated with tandems but a 40-40 not. Non-CTL are limited to use in older (pre 1968) panels.

The new Eaton panels can use non-CTL breakers as long as the number does not exceed the amount that is part of the listing. A 40/80 panel can use all non-CTL breakers

 

[Fred B]

The new Eaton panels can use non-CTL breakers as long as the number does not exceed the amount that is part of the listing. A 40/80 panel can use all non-CTL breakers

Why would you spend up to 3 times the price for non-ctl breaker, as a ctl would work on the 40/80 panel?

 

[infinity]

Why would you spend up to 3 times the price for non-ctl breaker, as a ctl would work on the 40/80 panel?

I'm pretty sure that the CTL breakers won't even fit in the new Eaton panels without the notched bus stabs.

 

[Fred B]

Well isn't that something. Eaton misleading advertising in that it forces a 3x cost breaker to fill capacity that is advertised. But if package markings are accurate the BRD is not a listed breaker for the panel.

 

[infinity]

Well isn't that something. Eaton misleading advertising in that it forces a 3x cost breaker to fill capacity that is advertised.

I think that since this is the direction that they're going one has to ask why one breaker cost 3x more than the other breaker.