Electrical panel nameplate

[lquadros]

I have had to fill up this nameplate a number of times, over the years. There are several details. Out of which, there is one that says interrupting capacity. This data has ranged anywhere from 65kA to 5kA. Would you know of a standard nameplate data that NEC chooses and does it have this item mentioned on a panel nameplate?

My understanding is that an electrical panel is not an interrupting device, hence it should not be mentioned. I agree with the item - short circuit rating or current withstand rating. Your point of view on this matter is greatly appreciated.

 

[petersonra]

I have had to fill up this nameplate a number of times, over the years. There are several details. Out of which, there is one that says interrupting capacity. This data has ranged anywhere from 65kA to 5kA. Would you know of a standard nameplate data that NEC chooses and does it have this item mentioned on a panel nameplate?

My understanding is that an electrical panel is not an interrupting device, hence it should not be mentioned. I agree with the item - short circuit rating or current withstand rating. Your point of view on this matter is greatly appreciated.

In general, only the manufacturer can affix a meaningful marking of some sort indicating the SCCR or the AIC. You could have UL or some other field evaluation company inspect it and affix such a nameplate as well.

The format of the marking is not a code issue.

 

[Aleman]

Article 409 covers control panels in the NEC (2011 shown) as below.
As far as I know you should be able to establish an SCCR for your panels if they don't have one. Basically it will be the same rating as the lowest rated component
in the panel. I recently compiled label data for about 20 panels where I work. These were built either by myself or other contractors and had no 'official' label or rating. As a plant safety project I had an Arc Flash study done and labels made for any panels that needed labels. There is a ton of info available on establishing SCCR ratings for panels on the net.
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409.110 Marking. An industrial control panel shall be
marked with the following information that is plainly visible
after installation:
(1) Manufacturer’s name, trademark, or other descriptive
marking by which the organization responsible for the
product can be identified.
ARTICLE 409—INDUSTRIAL CONTROL PANELS 409.110
2011
(2) Supply voltage, number of phases, frequency, and fullload
current for each incoming supply circuit.
(3) Industrial control panels supplied by more than one
power source such that more than one disconnecting
means is required to disconnect all power within the
control panel shall be marked to indicate that more than
one disconnecting means is required to de-energize the
equipment.
(4) Short-circuit current rating of the industrial control
panel based on one of the following:
a. Short-circuit current rating of a listed and labeled
assembly
b. Short-circuit current rating established utilizing an
approved method
Informational Note: UL 508A-2001, Standard for Industrial
Control Panels, Supplement SB, is an example of an
approved method.
Exception to (4): Short-circuit current rating markings are
not required for industrial control panels containing only
control circuit components.
(5) If the industrial control panel is intended as service
equipment, it shall be marked to identify it as being
suitable for use as service equipment.
(6) Electrical wiring diagram or the identification number
of a separate electrical wiring diagram or a designation
referenced in a separate wiring diagram.
(7) An enclosure type number shall be marked on the industrial
control panel enclosure.

 

[petersonra]

Basically it will be the same rating as the lowest rated component in the panel.

You can get a number that way. But it is unlikely to be the real number. For instance terminals normally have a basic rating of 10 kA. That does not mean that any panel that has a terminal in it is automatically 10 kA SCCR. GFCI receptacles have a rating of 2 kA. That does not mean a panel that has a GFCI in it is automatically 2 kA SCCR.

You certainly could use UL508a's SCCR procedure and come up with a number and it might even be the "correct" number (not likely if you used your suggested approach though). That does not mean the nameplate you created is especially meaningful.

 

[Aleman]

You certainly could use UL508a's SCCR procedure and come up with a number and it might even be the "correct" number (not likely if you used your suggested approach though).
That does not mean the nameplate you created is especially meaningful.

I did use UL508a's procedure and yes I came up with a real number. It isn't exactly rocket science. I was just making a generalization of what establishes an SCCR rating on a panel.
If the OP wants to do that then I would suggest reading up on it before doing it.

 

[Smart $]

While you are determining the SCCR for a label [110.10], you should also determine the maximum available fault current [110.24].

 

[petersonra]

I did use UL508a's procedure and yes I came up with a real number. It isn't exactly rocket science. I was just making a generalization of what establishes an SCCR rating on a panel.
If the OP wants to do that then I would suggest reading up on it before doing it.

You do understand that if you use the UL procedure to calculate the short circuit current rating you also have to abide by the other 200 pages in the UL 508a spec. That is a prerequisite to using the supplement that tells you how to calculate the short circuit current rating.

 

[Aleman]

While you are determining the SCCR for a label [110.10], you should also determine the maximum available fault current [110.24].

I agree with you. But what I need is a nameplate per my boss and that means establishing the SCCR for the panels. They are not supposed to be rated lower than
the available fault current I know. I don't have those numbers yet but am working on it. The vendor supplied UL listed panels we do have and any other panel we have
bought with a system have SCCR ratings on the labels. Those numbers were determined by the panel build itself regardless of the supply it was being hooked up
to. We do need to make sure we are ok in that our SCCRs are higher than available fault current. Otherwise I will need to do some rebuilding.

 

[Aleman]

You do understand that if you use the UL procedure to calculate the short circuit current rating you also have to abide by the other 200 pages in the UL 508a spec. That is a prerequisite to using the supplement that tells you how to calculate the short circuit current rating.

None of these panels will be nor are they required to be UL listed. If that changes I will worry about it then but most are built per UL508A.
We do have a few built by a previous contractor that would need to be rebuilt or replaced but for now I am just making them ok per NEC 409.
As I see it, per NEC 409 the only UL508a related requirement for our panels is the SCCR rating method given in UL508a supplement SB.