SCCR for RCCB

[Julio Chadrone]

I was trying to determine the SCCR for panel I have an RCCB placed before a circuit breaker. It is a 2 pole 16-amp 10 mA trip residual current circuit breaker. The site states the SCCR for this is 10 mA (same as residual current trip, but considering it is rated for 16 amps, does it mean it drops the SCCR for the panel from 5kA down to 10mA if I want to use this on the branch. I ask because it can it is rated for 16 amp so I don't know if putting 10 mA as the highest current it can handle is accurate, especially considering I have an MCB downstream right after it. the part in question is F202 AC-16/0.01

 

[jim dungar]

Somebody is mixing up terminology.
A RCCD is protecting against mA of leakage current, usually L-N faults.
A SCCR is about items being able to withstand kA of short circuit current, until the fault is cleared.
An AIC is also about kA and the protective device's ability to safely clear the fault.

 

[Jraef]

Also, SCCR is a terminology that refers to devices intended for use in North America, typically as listed by an NRTL (Nationally Recognized Test Lab) such as UL, CSA or ETL etc.

RCCB (Residual Current Circuit Breaker) is a term for a device used in countries OUTSIDE of North America and there is no "official" recognition of them in our system, the nearest we would have would be a GFEP (Ground Fault Equipment Protection) circuit breaker (not to be confused with GFCI, which has a specifically lower trip threshold that is not used outside of NA). So you will not find an SCCR on an RCCB, because you are asking for something that requires testing, on a device that is not tested and listed for use here at all.

 

[Julio Chadrone]

For some branch circuit breakers, I can't find an SCCR, and only an AIC. I've read somewhere, but haven't confirmed that the AIC, clearing current can be considered the SCCR for branch circuit breakers which is something I thought sounded right, but didn't get confirmed.

But from the UL course I know that every piece of equipment in ap power circuit needs to have an SCCR. and for RCCB's they are used in power circuit branches so I figured if the RCCB is UL listed, which this one is, it would have had to gone through some sort of testing to get an SCCR rating.
I did find something though, in the document sheet it states if in line with 100-125A class gL or gg fuses the SCCR for this RCCB is 10 kA, but I don't think gL are UL recognized type fuses. So, what I'm getting is this is UL rated, but to put it in a UL approved enclosure, I need to mark it with 10 mA sccr, unless I throw non-UL approved fuses upstream which would disqualify it, for UL approval?

 

[Jraef]

SCCR refers to EQUIPMENT, meaning that you have multiple devices in a unit and together, there is an overall SCCR that is based on EITHER the LOWEST rated device inside, a "series listing" of devices, or at the very least, an untested / unlisted "courtesy" listing of 5kA. The problem is, 5kA is basically useless in the real world.

Breakers alone have an "Interrupt Capacity" (AIC), which would be used as PART of an SCCR if they are in an assembly. So if a breaker by itself is listed at 10kAIC, then the most an assembly using them can have is an SCCR of 10kA, unless the breaker is "Series Listed" with a Main breaker for a higher value, for example 22kAIC is common. In that case then, a panel using that SPECIFIC combination could have an SCCR of 22kA.

You say that RCCB is "listed"? As what? It makes a difference. If it is UL listed under UL489, that is a legit "circuit breaker" and would be REQUIRED to have an AIC rating as part of that listing. If not, it might be "listed" under UL1077, which is for a "supplementary protector", something different from a circuit breaker, which is then REQUIRED to be used DOWNSTREAM of another listed protective device, either a UL489 listed breaker, or a fuse that is UL listed as BRANCH protection (not all of them are). So if their documentation says it is required to have gL fuses ahead of it, that would NOT be a legitimate listing for use in North America, because gL fuses are NOT listed for Branch protection here.

But I think you are still missing something here; "10mA SCCR" would be WORSE than having NO SCCR... 10mA is likely the RCD trip level, which has nothing to do with the IC rating.

 

[Julio Chadrone]

Thanks that at least makes me aware of some things I didn't even consider when sourcing my parts. It is rated under UL 1053, which is for ground fault current sensing devices. Yeah the 10 mA was insanely bad, and it didn't make any sense when considering the part itself stated it could handle 16A current. Which is like saying it can handle continious current of up to 16A but if it shorts it can only handle up to 10 mA. But also, if the site itself states





I don't think I can just say no manufacturers, you are incorrect, even if it doesn't really make sense how both these statements can be true.

 

[Jraef]

OK, so the REASON why they are saying this is because although this LOOKS like a "circuit breaker", it is NOT, it is a SWITCH that also has an RCD function to trip at 10mA. So it doesn't have an "interrupt" rating as we consider it for SCCR purposes, because it is not going to "interrupt" any fault (above 10mA). That's likely why they are saying the "SCCR" is only 10mA, because it really has none. Even though they apparently got a UL1053 rating on it, you cannot use it in any way here. They SELL them here, but you can't actually USE them here...

Incidentally, I think you will find that the SYMBOL on the device indicating it's UL status will be a backward UR, meaning it is a "Recognized Component" and thus ONLY able to be used as PART of a UL listed SYSTEM with other devices that are necessary for it's use. That's not the same as being "listed".

Just out of curiosity, what are they for in your system? I ask because there might be a better way to accomplish what you need. These things are more trouble than they are worth.

 

[petersonra]

I think the 10 mA SCCR is likely a mistake. Maybe when it was printed up in china the guy that translated it to English just wasn't a real good translator.

 

[petersonra]

Why not call abb and ask. I don't think there is any valid use for this part in the US anyway.

 

[Julio Chadrone]

It's for a power distribution panel I am designing for heater purposes. The enclosure is going to be used outside of the US. I don't 100% know exactly what is being heated, but I was informed the client wanted earth leakage/ground fault protection on every zone output zone on the panel, as well as overcurrent protection. I sourced this for the ground fault protection and have a regular circuit breaker downstream for overcurrent protection. I am guessing they want this rather than a current transformer with an earth leakage relay system up front so that if one zone trips it doesn't shut down all of their processes.

By can't use them here you mean cannot use them in equipment being operated in the United States?

Also I did end up contacting ABB just to see if they can confirm what is on the data sheet is correct waiting on them for that, will update with their response.

 

[petersonra]

Sccr is a US thing. I don't think that getting a ul508a listing for the panel would help you out any overseas. And the only way to get a meaningful sccr is to ul508a list it.

 

[Jay Kramer]

It's for a power distribution panel I am designing for heater purposes. The enclosure is going to be used outside of the US. I don't 100% know exactly what is being heated, but I was informed the client wanted earth leakage/ground fault protection on every zone output zone on the panel, as well as overcurrent protection. I sourced this for the ground fault protection and have a regular circuit breaker downstream for overcurrent protection. I am guessing they want this rather than a current transformer with an earth leakage relay system up front so that if one zone trips it doesn't shut down all of their processes.

By can't use them here you mean cannot use them in equipment being operated in the United States?

Also I did end up contacting ABB just to see if they can confirm what is on the data sheet is correct waiting on them for that, will update with their response.

Where outside US is to placed?
If it's within the EU the panel must comply with the relevant IEC/EN standards.
Panels used for controlling machines or similar must comply with IEC/EN 60204-1:2018.
Panles used for i.e. Main panels above 250A has to comply with IEC/EN 61439-1 and 61439-2

 

[Julio Chadrone]

Where outside US is to placed?
If it's within the EU the panel must comply with the relevant IEC/EN standards.
Panels used for controlling machines or similar must comply with IEC/EN 60204-1:2018.
Panles used for i.e. Main panels above 250A has to comply with IEC/EN 61439-1 and 61439-2

I am not sure where outside the US it is being placed, but most likely not the EU, since we offer only UL certification on our products not IEC/EN.