Does series rating care about panelboard enclosure rating?

[binwork91]

When we consider fully rate panelboard, we need to consider panelboard enclosure AIC rating and breaker AIC rating. The lower number will be the fully rating number.
For example. enclosure is 65kaic, breaker is 42kaic. then this panelboard is 42kAic fully rate.

what about series rating?

If panelboard "P" enclosure is 65kaic, branch breaker "B" is 42kaic. and the breaker "B" is able to series rate with upstream device "A" up to 100kaic.
question: if the fault current at this panelboard is 70kA, can we say this panelboard is 100Kaic series rate or 65kaic series rate? Is this panelboard good for this 70kA fault?

 

[jim dungar]

When we consider fully rate panelboard, we need to consider panelboard enclosure AIC rating and breaker AIC rating. The lower number will be the fully rating number.
For example. enclosure is 65kaic, breaker is 42kaic. then this panelboard is 42kAic fully rate.

what about series rating?

If panelboard "P" enclosure is 65kaic, branch breaker "B" is 42kaic. and the breaker "B" is able to series rate with upstream device "A" up to 100kaic.
question: if the fault current at this panelboard is 70kA, can we say this panelboard is 100Kaic series rate or 65kaic series rate? Is this panelboard good for this 70kA fault?

Panelboards do not have an Amps Interrupting Capacity (AIC) rating. Because they do not break the fault current, they have a Short Circuit Current Rating (SCCR) instead.

Yes the SCCR rating needs to be considered and it could be the limiting factor, although it normally isn't. Panels are often limited to the fault current value of the lowest installed protective device.
There are no series ratings for panel bussing, although some manufacturers may offer something like an integrated equipment rating or a series combination rating.

When describing fault ratings the correct term is SCCR, which takes into account the panelboard bussing and the series or full AIC ratings of the protective devices. In your example you would say panel "P" has an SCCR of 65kA.
However if the panel is really rated based on the lowest AIC of installed devices, you could say it has an SCCR of 70kA.

 

[binwork91]

Panelboards do not have an Amps Interrupting Capacity (AIC) rating. Because they do not break the current they have a Short Circuit Current Rating (SCCR) instead.

Yes the SCCR rating needs to be considered and it could be the limiting factor, although it normally isn't.
There are no series ratings for panel bussing, although some manufacturers may offer something like an integrated equipment rating.

When describing fault ratings the correct term is SCCR, which takes into account the panelboard bussing and the series or full AIC ratings of the protective devices. In your example you would say panel "P" has an SCCR of 65kA.

Thank you for the explain.
If panelboard "P" enclosure is 65ka SCCR, branch breaker "B" is 42kaic. and the breaker "B" is able to series rate with upstream device "A" up to 100kaic.
question: if the fault current at this panelboard is 70kA, can we say this panelboard is 100Kaic series rate or 65kaic series rate? Is this panelboard good for this 70kA fault? I wonder if I need to ask supply house to change the panelboard SCCR to 100kA.

 

[jim dungar]

I wonder if I need to ask supply house to change the panelboard SCCR to 100kA.

Yes, you need a panel with an SCCR of at least 70kA.
But ask the supply house what the panel label really says.
Depending on the brand, the panel likely has a label that says its SCCR is limited to the lowest AIC of any installed breaker. So even if you ordered a 65kA panel, the panel interior you got may be suitable and their ordering information/records simply needs to reflect that a series rating is being employed.

 

[binwork91]

Yes, you need a panel with an SCCR of at least 70kA.
But ask the supply house what the panel label really says.
Depending on the brand, the panel likely has a label that says its SCCR is limited to the lowest AIC of any installed breaker. So even if you ordered a 65kA panel, the panel interior you got may be suitable and their ordering information/records simply needs to reflect that a series rating is being employed.

Thank you for answering my question. It solves my concern.

 

[Jraef]

However if the panel is really rated based on the lowest AIC of installed devices, you could say it has an SCCR of 70kA.

Was that a typo? The BRACING of the busbars in that panel is rated for 65kA. There is no "series rating" for bus bar bracing so even if the DEVICES have a series rating of 100kAIC, the panel itself is still only 65kA so the SCCR cannot be higher than 65kA. If you have 70kA Available Fault Current at the terminals, you cannot use that panel. At least, that's how I understand SCCR, maybe I'm wrong?

 

[jim dungar]

Was that a typo?

No.
You did not read my statement.
I said if the panelboard contains a label that says its SCCR is based on the lowest AIC of devices installed in it, then the OP may be okay, even if he ordered a 65kA panel.

Switchboards and Motor Control Centers require specific bus bracing, however panelboard bussing is typically continuously braced and so it commonly has ratings of 100kA or more as standard.

For example the Siemens catalog says "The panel design provides bracing up to 200,000A IR UL short circuit rating." Increased bus bracing is not even listed as a typical modification for panel interiors.