Maximum ampere rating of the short-circuit device?

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wireman

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Our customer requires a control panel's nameplate to have among other things the:

"Maximum ampere rating of the short-circuit and groundfault protective device, where provided."

Is this the short circuit rating of the main fuses (in our case we don't have any GF protective devices in the panel)?

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They also requiring the SCCR rating (100kA in this case).

Thanks in advance for any replies
 

Jraef

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Electrical Engineer
Our customer requires a control panel's nameplate to have among other things the:

"Maximum ampere rating of the short-circuit and groundfault protective device, where provided."

Is this the short circuit rating of the main fuses (in our case we don't have any GF protective devices in the panel)?

==================
They also requiring the SCCR rating (100kA in this case).

Thanks in advance for any replies

Let's break it down:
"Maximum ampere rating of.."
Means what is the SIZE (Amp rating) OF the device?

"...the short-circuit and groundfault protective device..."
Think in terms of the NEC usage of this term. They mean the Circuit Breaker or Fuses, they do not know what you plan to use. Ground Fault Protective Device, as used generically in this context, is one of the things any circuit breaker or fuse does; it protects against short circuits, defined as phase-to-phase shorts, or ground faults, defined as phase-to-ground shorts. You are confusing this with a Ground Fault Circuit Interrupter, totally different device.

"... where provided."
They don't know if you are even providing this, but IF you are, you must state what these values are.

They also requiring the SCCR rating (100kA in this case).
SCCR (Short Circuit Current Rating) is a maximum available fault current that the piece of equipment being installed must be capable of handling safely. It is not just the interrupt rating of the protective devices, it is a combination of that and the ability of anything down stream of it to handle what gets past the main device before it has a chance to interrupt the flow, commonly referred to as the "let-through" current.

Given that you do not know what all this is, it's a safe bet you are not qualified to attain it, you are not a UL-508A panel shop, and you are in trouble. This has been a requirement in the NEC, article 409, for industrial control panels for quite some time now (2005 code). The wording they have used is almost verbatim out of Article 409, where it describes the minimum necessary labeling requirements. By the way, 100kA is going to be VERY difficult to attain. Did you know this when bidding on it? Because if you are bidding on it now, you might want to consider passing, it will be next to impossible.

http://www.schneider-electric.us/si...ng-the-impact-of-nec-article-409-ul-508a.page
 
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