WCR RATING - KOHLER AUTOMATIC TRANSFER SWITCHES

[PE (always learning)]

Hey everyone,

I apologize, I know I have been posting a lot recently and I appreciate all of your help. Here is another question that has been bothering me and its related to the withstand and close on ratings for Kohler Automatic Transfer Switches. The cut sheets give three scenarios for transfer switch ratings: With Current-Limiting Fuses, Specific Coordinated Breaker, and any breaker. I have attached a cut sheet showing the conditions for my breaker which fall under "N/A". My question is if I fall under not applicable, is there a minimum rating that this transfer switch has even though it says "N/A". I have tried contacting the manufacturer and sales representative who weren't of much help and sent my question on to the "technical guru". They said it would take a week or longer to get back to me. The model number for this transfer switch is KSS-AMVA-0600S and it is being protected by a breaker that is not on the list of specific breakers. Again, I know this is more of a technical question to ask the manufacturer, but I'm curious if anyone else has seen this before.

Best Regards

 

[ron]

Unfortunately you are out of luck. It has no withstand rating with "any" 800A breaker.

ATSs are constantly failing when I do SCCSs. Un-fused disconnect switches too. grrrrr

 

[PE (always learning)]

Seriously? So there's not even like a minimum rating for the ATS? This is on the emergency branch and all I would need is a rating of 10kA to be protected. That's very surprising to me.

 

[Ingenieur]

Seriously? So there's not even like a minimum rating for the ATS? This is on the emergency branch and all I would need is a rating of 10kA to be protected. That's very surprising to me.

it is only rated for use with the specified cb's
not even i limiting fuses

 

[jim dungar]

I have tried contacting the manufacturer and sales representative who weren't of much help and sent my question on to the "technical guru". They said it would take a week or longer to get back to me.

You don't get what you don't pay for. You need to stop buying from suppliers like this, or they will never start providing legitimate support.
I would guess that transfer switch vendors get asked this type of question at least once a week, if not once a day (nationally). Article 110.10 has been in the NEC for decades.

The manufacturer may respond that they never bothered to get an 'any breaker' rating, in which case you will need to either change your protective device or change your switch.

 

[wbdvt]

I think only choice is to replace the upstream breaker with a listed one or find another ATS. Also, I would think the upstream breaker would have to be listed for both the Normal and Emergency feed.

 

[publicgood]

This simply means it was not tested for this rating and cannot be applied for SCCR. You'll need fuses or specific breaker. The specific breaker must be that exact breaker and trip unit: UL 1008 7th Edition

 

[publicgood]

Note 2017 NEC (I believe) has the contractor field labelling the SCCR on the outside of the ATS.

 

[jim dungar]

Note 2017 NEC (I believe) has the contractor field labelling the SCCR on the outside of the ATS.

Are they field labeling the amount of available fault current, or Short Circuit Amps (SCA)? The SCCR would comes from the equipment manufacturer.