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 Post subject: Fusible Disconnect - Low Voltage
PostPosted: Wed Feb 20, 2019 12:01 pm 
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Lets begin this new forum topic regarding the new IEEE 1584 and electrode configurations with a simple low voltage fusible disconnect. What are your thoughts regarding which electrode configuration(s) to use?

Please provide your thoughts about the configuration and the specific location on the equipment if applicable.


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 Post subject: Re: Fusible Disconnect - Low Voltage
PostPosted: Fri Feb 22, 2019 9:38 am 

Joined: Tue Dec 31, 2013 12:19 pm
Posts: 32
The fuse clips could be HCB. The lugs could be VCBB. All else being equal, if you run the calcs on both HCB and VCBB, HCB gives you the higher incident energy. So I would use HCB.


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 Post subject: Re: Fusible Disconnect - Low Voltage
PostPosted: Fri Feb 22, 2019 9:42 am 

Joined: Tue Dec 31, 2013 12:19 pm
Posts: 32
IEEE 1584-2018 Annex C.4 says "VCBB is likely to be the best configuration." So from that language, I wouldn't have a problem using VCBB.


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 Post subject: Re: Fusible Disconnect - Low Voltage
PostPosted: Fri Feb 22, 2019 11:01 am 
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Jeff S wrote:
IEEE 1584-2018 Annex C.4 says "VCBB is likely to be the best configuration." So from that language, I wouldn't have a problem using VCBB.


That is correct, you have to follow the flow of current, This is an opinion, however, the majority of the nodes in a typical 600V Class study are going to be VCBB, The notable exceptions are all bus plugs and breakers in true switchgear construction (versus swithchboard construction), these are horizontal.

Also be cautious on how you classify the low voltage side of a pad mount transformer. Those appear to be horizontal, however, the LV chamber is a hybrid open-air enclosure with extremely large bus separation. The bus separation could be 6"-12".


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 Post subject: Re: Fusible Disconnect - Low Voltage
PostPosted: Mon Apr 01, 2019 11:19 am 

Joined: Mon Nov 24, 2008 6:42 pm
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Location: Nashville, TN
Again, Jim, no disrespect, but how would any of us end-users who were not intimately involved in developing the IEEE 1584-2018 have any idea of what you meant when you introduced these electrode configurations?

You are the Vice Chair of IEEE 1584-2018.

So what electrode configuration is this please?


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 Post subject: Re: Fusible Disconnect - Low Voltage
PostPosted: Mon Apr 01, 2019 1:43 pm 
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mgoslak wrote:
Again, Jim, no disrespect, but how would any of us end-users who were not intimately involved in developing the IEEE 1584-2018 have any idea of what you meant when you introduced these electrode configurations?

You are the Vice Chair of IEEE 1584-2018.

So what electrode configuration is this please?


Agreed. I just finished an article about this issue and I compare it to the introduction of the first edition of IEEE 1584 in 2002. In 2002 we had a new standard but getting comfortable about the application details took a while - Many of the questions seem trivial in hind sight but a big deal back then.

That is where I believe we are now. We have the standard - now the application details need worked out. There is some guidance in the standard but more will become available with subsequent papers (I have one this September at PCIC along with a few colleagues) with other people's papers following. - Similar to 2002. Thanks for your comment!


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 Post subject: Re: Fusible Disconnect - Low Voltage
PostPosted: Mon Apr 08, 2019 1:54 pm 

Joined: Mon Nov 24, 2008 6:42 pm
Posts: 5
Location: Nashville, TN
So Jim,
You are not going to tell us what electrode configuration to use for the "simple" fusible disconnect switch?

What do you tell your clients in your "how to perform an arc flash hazard analysis" class?

This is ridiculous. You did the testing but then left us hanging with these vague electrode configurations.

How is the end user supposed to know what the intentions were of the authors of the IEEE 1584-2018 standard? You used laboratory electrode configurations that don't relate to anything you see in the real world.

Now we are left wondering what to do and I don't hear anyone coming forward from the IEEE 1584-2018 committee to offer and hand in clarifying this!!

SHAMEFUL.


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