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ekstra   ara
 Post subject: Modeling Question
PostPosted: Tue Aug 30, 2022 11:32 am 

Joined: Tue Jun 14, 2022 11:35 am
Posts: 5
I have a old FPE switchboard that has two fuses per phase. In the attached image you have 300-amp fuses with 300 MCM cable. I am assuming for proper results in SKM this would need to be modeled as a 600-amp fuse with parallel 300 MCM. Any thoughts or suggestions on modeling this?


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 Post subject: Re: Modeling Question
PostPosted: Wed Aug 31, 2022 2:21 am 
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Location: Indiana
?

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DOUBLE FUSES.jpg


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 Post subject: Re: Modeling Question
PostPosted: Thu Sep 01, 2022 8:01 am 

Joined: Tue Jun 14, 2022 11:35 am
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Thanks bbaumer, I suppose I should have asked my question with more detail. I am really concerned more with the TCC as I have a 300-amp breaker in the panel downstream of the 300-amp fuses. We really have a 600-amp feed to the panel. I can make the drawing look like the picture, but with a 300-amp fuse the TCC does not tell the story.


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 Post subject: Re: Modeling Question
PostPosted: Thu Sep 01, 2022 4:16 pm 
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Is this your facility or a customer's?

If it's yours, and you only have a 300 amp rated panel downstream, remove one set of fuses and disconnect the corresponding set of conductors at the panel.

Or

Replace the fuses with 150's, although I think removing one set of fuses would be more appropriate.

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 Post subject: Re: Modeling Question
PostPosted: Fri Sep 02, 2022 2:24 am 
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I just re-read your last post. Is the 300 amp breaker in the downstream panel a main?

The panel itself would be protected from overload by the main in that case.

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 Post subject: Re: Modeling Question
PostPosted: Fri Sep 02, 2022 12:33 pm 

Joined: Tue Jun 14, 2022 11:35 am
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bbaumer wrote:
I just re-read your last post. Is the 300 amp breaker in the downstream panel a main?

The panel itself would be protected from overload by the main in that case.


MLO panel the 300-amp is a feeder out of the panel.


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