AIC rating for LCP & Lighting Relays

[necnotevenclose]

Does the AIC rating for lighting control panels (LCP) & lighting relays need to be rated for the available fault current?

I've done some web research and it appears some peoples thoughts are no because the relays are switches and not an OCPD. Is this correct?

What about the LCP? Would I be able to apply NEC 2008 409.110(3) Exception?

 

[Jraef]

AIC = Amps Interrupting Capacity. The key word is Interrupting. That means interrupting a FAULT, not the normal day-to-day operations. A relay or any control device is not intended to interrupt a fault, that is the job of the OCPD; the fuse or breaker.

But in the course of day-to-day operation, if there is a fault on the down stream side of a control device, it will have to WITHSTAND the fault current until the OCPD can sense, react and interrupt the fault. That is (was) called the Withstand Rating, now it is called the SCCR (Short Circuit Current Rating) of the device since the release of the changes to Article 409 in the NEC a few years back.

So to that end, relays and anything else in a circuit must have an SCCR that is equal to or greater than the Available Fault Current (AFC) in a circuit. Generally, if a component or panel (such as an LCP) has not been specifically tested and listed with an SCCR, you have to assume it is rated for no more than 5kA. But if, in the case of most LCPs now offered by the major panelboard / breaker mfrs, the system is used with the mfrs own breakers, they typically will have been tested by them and listed to have an SCCR level the same as the OCPDs up stream. You have to check though.

 

[skeshesh]

...Generally, if a component or panel (such as an LCP) has not been specifically tested and listed with an SCCR, you have to assume it is rated for no more than 5kA.

As a matter of interest, is the statement above based on experience or is there some sort of industry standard involved?

 

[Jraef]

As a matter of interest, is the statement above based on experience or is there some sort of industry standard involved?

That's basically what Article 409 says about unevaluated devices.

 

[jim dungar]

As a matter of interest, is the statement above based on experience or is there some sort of industry standard involved?

Look at UL508A for some more guidance.

 

[necnotevenclose]

Thanks guys for your replies.

From what I understand LCP and the relays should have a rating that meets or exceeds the available fault current. I've done a little bit of research I'm finding that the standard LCP is either rated for 14k AIC (277V) or 10k AIC (120V).

I found that LC&D offers an LCP panelboard that can be rated upt o 65k AIC as long as you use a main. I can see using that on a large project, but what about the smaller TI's. Would anyone happen to have any suggestions?

again, thanks guys.

 

[skeshesh]

You already answered your own question in the first part of your last post: your rating will depend on the available short circuit current at the point in the electrical system where you will be placing your panel. It is generally correct to say something like a 65KAIC LCP will be used in larger facilities, but really it will depend on the available SC. Even in many large plant or facilities, a lighting control panel may be far off downstream in the electrical distribution or otherwise have a limited available fault, allowing you to use 10KAIC equipment. If you have a single line diagram of the system you're working with and know where you will be connecting the new panel post it for a comments about your particular case.