confusing language on Siemens load center

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RustyShackleford

Senior Member
Location
NC
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electrical engineer
I'm looking at the label on this Siemens plug-on neutral load center: https://www.cityelectricsupply.com/...-225a-42-spaces-64-circuits-copper-bus-nema-1

PN4264B1225C label.jpg

It is designated for 42 spaces and 64 circuits. With the 42 spaces, you could have 84 circuits by using space-saver breakers (type QT in Siemens parlance) in every position. Siemens enforces the 64-circuit limit by providing only 22 of the 42 stabs with the notch with allows a space-saver breaker. (Of course this can be circumvented by using non-CTL breakers, but this is non-code compliant unless the panel is very old, made prior to 1965 I believe).

So far, so good.

But then note the language on the far-right of the label: "The installed neutrals limit this panelboard to 64 circuits that require neutral connections. If up to 84 circuits are needed, instal ECNBX kit(s) per schematic."

What on earth does this mean ? You're allowed to use non-CTL breakers to populate up to 84 circuits, if you simply install extra neutral bars ? If so, would this be code-compliant ? Siemens seems to be instructing you to do this if desired; does this override the rule about not using non-CTL breakers on newer panels ?
 
RustyShackleford said:
It is designated for 42 spaces and 64 circuits. With the 42 spaces, you could have 84 circuits by using space-saver breakers (type QT in Siemens parlance) in every position. Siemens enforces the 64-circuit limit by providing only 22 of the 42 stabs with the notch with allows a space-saver breaker.
Click to expand...
Where does it say that only 64 circuits can be used? It sounds like once you add the additional neutral bar it becomes an 84 circuit panel for 84 neutrals.
 
infinity said:
Where does it say that only 64 circuits can be used? It sounds like once you add the additional neutral bar it becomes an 84 circuit panel for 84 neutrals.
Click to expand...
I suppose it doesn't, explicitly, except maybe for the chart at the top=center of this schematic.

PN4264B1225C schematic.jpg
If they didn't mean it to be explicit, why on earth did they make only 22 of the stabs able to accept QT breakers (without using non-CTL type) ? Were they afraid people would violate the requirement of each neutral having a dedicated screw on the bar ?
 
RustyShackleford said:
If they didn't mean it to be explicit, why on earth did they make only 22 of the stabs able to accept QT breakers (without using non-CTL type) ? Were they afraid people would violate the requirement of each neutral having a dedicated screw on the bar ?
Click to expand...
Who knows. I know that Eaton panels listed as 40/80 just use non-CTL breakers to get the 80 circuits.
 
I think this must just be a screw-up on the label. The spec sheet says 64 circuits. Also, the only other bigger panel Siemens lists is a 54-space, 82-circuit. FWIW, I do count 64 branch neutral terminals on the stock bars.
 
Electromatic said:
FWIW, I do count 64 branch neutral terminals on the stock bars.
Click to expand...
Right, which is why they say you need to add the neutral-bar extension kits if you want more circuits. Which of course you don't necessarily need if you have some 2-pole loads that don't require neutrals (since they count as two circuits).
 
It says "Accepts type QT breakers for a max of 64 circuits" so I don't think that it is labeled incorrectly.
 
RustyShackleford said:
So what are they trying to say with the wording I highlighted in OP ?
Click to expand...
It cannot utilize more than 64 circuit breakers. Why you would need more than 64 holes for neutrals in this panel is a mystery when it's clearly labeled as to being limited to no more than 64 breakers.
 
Likely, because they OFFER a panel that can go larger, the printing on this label is the same for both panels.

You cannot use Non-CTL breakers in a panel unless the panel listing and the breaker listing Specifically allows it. Maybe the Eaton that Infinity mentioned does? The entire concept of CTL and the 42 circuit limit was basically scrapped years ago, so it’s possible that Eaton just added their Non-CTL tandems to their panel listing and removed the “Only for use in panels made before 1968” qualifier from the breaker listing, problem solved!

In this case though, the Siemens PANEL does list “QT” breakers, which are the tandems, but the Non-CTL versions have an “NC” suffix. The problem is, Siemens still says that the NC variant of the tandem breakers is “For replacement use only in panels manufactured before 1968.” So using them in a new panel would be a 110.3(B) violation.
 
Jraef said:
Likely, because they OFFER a panel that can go larger, the printing on this label is the same for both panels.
Click to expand...
Nope. The larger panel allows 82 circuits not 84. And the label for it has similar wording, saying you can go to 100+ circuits with add'l neutral bar ...
 

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RustyShackleford said:
Nope. The larger panel allows 82 circuits not 84. And the label for it has similar wording, saying you can go to 100+ circuits with add'l neutral bar ...
Click to expand...
Ignoring the wording about the neutral expansion it's only listed as a 64 circuit panel so what is the actual problem? Do you need more than 64 circuits?
 
infinity said:
it's only listed as a 64 circuit panel so what is the actual problem? Do you need more than 64 circuits?
Click to expand...
It's inconvenient to be unable to put QT breakers into the 10 positions closest to the main breaker. That would require non-CTL breakers, which the wording suggests is acceptable - since there's no other way to achieve the 84 circuits that it says are available simply by adding neutral-bar extensions.
 
RustyShackleford said:
It's inconvenient to be unable to put QT breakers into the 10 positions closest to the main breaker. That would require non-CTL breakers, which the wording suggests is acceptable - since there's no other way to achieve the 84 circuits that it says are available simply by adding neutral-bar extensions.
Click to expand...
From the information on the spec sheet in post 3 there is an obvious conflict between that (max 64 circuits) and what is on the spec sheet in post #1 which mentions the neutral expansion. Only Siemens can answer why the two don't match. Regardless given the model number, the chart in post #3 and the explicit mention of QT breakers in only the bottom slots 64 is maximum number of circuits that you can use in this panel. Have you tried to contact Siemens so that they can explain the discrepancy?
 
Is like when you get drawings with boiler plate specifications. They didn't bother to check to see if everything they copied from every other design spec actually applies to this design.
 
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