How to compare NSX and Square D Q0 Trip Curves

[Korkmaz]

In our project, we will use NSX MCCB and Square D QO MCB. We can compare and see their curves in ETAP, but some of the CB instantaneous short circuit curves intersect. We generally use energy selectivity in such cases, but Square D is used in the USA while NSX MCCB is used in Europe. Therefore, we couldn't find any table or information about the energy selectivity of these circuit breakers. How can we find or compare information about these circuit breakers?

Thank you in advance for your help and guidance.

[Gregoire_Brun]

Hello @Korkmaz 

Your application looks strange for me because to mix a product certified Ul489 and another certified IEC 60-947-2

What can be the standard for your equipment on this case?

Maybe if you need UL products, it should be better to use Powerpact B H J L to replace the compact NSX  

[Korkmaz]

Maybe it better , but i want to know that how can i compare two circuit breaker according to energy selectivity without tables ?

[Gregoire_Brun]

please check if this tool can help you

EcoStruxure Power Design – Ecodial | Schneider Electric TR (se.com)

[Korkmaz]

Hello @Gregoire_Brun 

I appreciate your support and responses , i checked and installed Ecodial but couldn't find Square D type circuit breakers in Ecodial only find NSX and other type of europe side circuit breakers

[Gregoire_Brun · Accepted solution]

Hi @Korkmaz I double check on my side with some other expert in Usa 

Maybe you can ask the question on this topic

Ecodial Presentation - Schneider Electric Community

[Yarom · Accepted solution]

I used to support locally in North America the Square D UL protection devices. Then I moved to where IEC is the standard.

Let's understand first a bit of the background.  You cannot really compare such curves as each type (QO/U, NSX, PowerPact and so on) are tested specific to the standard for which they are intended. The standards of how trip curves work in UL do not necessarily coincide with those of the IEC. Although PowerPact are similar, they are not necessarily interchangeable. There are some NSX breaker that have UL and IEC ratings.

What this gives is so that you can install in either place (where UL or IEC is accepted by law), but according to regulations of that standard for which your panel must adhere.

For example, in the U.S. and Canada they follow UL 489, 508, 1077. Each has a specific application.

489 = Branch Circuit
508 = is a combination for the panel including Feeder circuit and Branch circuits at minimum.
1077 = Supplementary protection for control circuits.

Feeder Circtuit
Incoming to the panel and feeding all the branches, you must install a 489 breaker or UL 98 fuse or non-fuse (separate fuse holder) disconnect switch or UL 248 combination fused disconnect switches. to feed anything below.

Branch Circuit

If you have a control transformer dropping 480/600 (2 phases) to 230 or less single phase to a group of control devices, you must have the 489 type breaker at the primary and can use the 1077 type miniature circuit breaker at the secondary, for any of the control side wire protection.

This is a mere basic example of the complexities of breakers in UL panels. These standards are designed and tested. The IEC does not follow this method of protection. IEC follows as EcoDial shows and is programmed, to calculate cascading, selectivity, cables and other electrical properties.

UL has another property required -> SCCR (Short Circuit Current Rating)

IEC does not consider SCCR. This again, from the graphs of IEC breakers, tells us the energy and from there we calculate cables and busbars (again EcoDial).

To understand more about this UL information, please download the Schneider Electric Technical guide:

https://www.se.com/us/en/download/document/CPTG005_EN/ 

QO trip curves can be found in the catalog:

https://www.se.com/us/en/download/document/0730CT9801/

Any other trip curve can be found in their respective catalog.

For NSX breakers, use the Country website following IEC standards.

For PowerPact breakers, use the U.S. or Canadian website.

Conclusion:

Since UL and IEC are not equivalent standards, but alternatives, we cannot compare the two as they are not tested following the same standards. Each type has a curve generated according to the standard.

[zolos9479]

I would like to clarify the following question with you:
According to the Control Panel Technical Guide, can I use the Multi 9 M9F42350 https://eref.se.com/us/en/scope/product/M9F42350 as Feeder circuits (Incoming protective devices)? It complies with UL489, but its rated operational voltage is max.440V according to the datasheet. How then can I use it for three phases 480Y /277V. Also, what does "..." mean in the table on page 20?
Or on the input option only https://www.se.com/us/en/product/EDB34050/mini-circuit-breaker-eframe-50a-3-pole-480y-277vac-25ka-ma... or https://www.se.com/us/en/product/BDP36050/circuit-breaker-powerpact-b-50a-3-pole-600y-347vac-14ka-lu...
Thank you for your answer

[Gregoire_Brun]

hello @zolos9479 

I wouldn't recommend tuo use the multi9 product for your needed , an dI recommend to use the powerpact B for this application

[Yarom]

Let's clear up a little bit.

You looked at the M9F42350. The Multi9 series is designed for OEM usage, and were give multiple standards.  We see the UL489 as well as IEC947.

You have to be careful when reading datasheets. When you open the datasheet that you referred:

https://eref.se.com/us/en/scope/product/M9F42350, look at the table of standards for the breaking capacity values.

6 kA Icu 440 V AC EN/IEC 60947-2
10 kA Icu 415 V AC EN/IEC 60947-2
20 kA Icu 240 V AC EN/IEC 60947-2
6 kA Icu 440 V AC GB 14048.2
10 kA Icu 415 V AC GB 14048.2
20 kA Icu 240 V AC GB 14048.2
10 kA AIR 240 V AC UL 489
10 kA AIR 240 V AC CSA C22.2 No 5

440V is rated for Countries following the IEC (European) and GB has it's own. These countries run 400V 3phase +/- 10% allowance. Hence, the 440V value.

Nowhere does it mention UL489 for those voltage ratings. For UL489, you can use it on up to 240V. So you can use it as a feeder to a branch that has an oven rated 208V ph-ph for example.

For more details on this series of circuit breaker, you can download the catalog:

https://www.se.com/us/en/download/document/LVCATM9OEM_EN/

Regarding the question of 480/277, the EDB breaker is an original Square D brand breaker, designed for the U.S. market. The use standard industrial 3 phase voltage is 480V phase to phase, which gives 277 phase to neutral. So for any application or equipment using those standard voltages (277V Ph-N could be lighting, 480V Ph-Ph could be a 3 phase motor), you would use this type of breaker for the branch circuit.  It is tested and certrified according the UL and CSA standards.

In Canada, the standard industrial voltage is 600V Ph-Ph or 347V Ph-N. Here, the EDB will not satisfy equipment connecting to this electrical network.

The PowerPact B breaker does satisfy the conditions to work up to 600V Ph-Ph / 347V Ph-N.

Again, all these have to do with the requirements of the regional standard. It is not a question about take something cheaper that seems close enough or why is it 40V too low for what is needed. Do not forget that 10% +/- has to be taken into account. 440V is the maximum.  And to get back to the original question, because of the difference in standards, thereby, different testing procedures and requirements, they cannot be necessarily compared.

As Gregoir Brun mentioned, for your application, it is best to stick with PowerPact B.

Best regards