# Single phase 480v



## WronGun (Oct 18, 2013)

We have been relocating and adding equipment in a large manufacturing plant. 

Needless, to say I’m in a complete different world than I’m used to, not much industrial experience. 

So we are adding some new equipment that is spec’d out for single phase 440/460 @40A. 

Is this simply a DP circuit coming from a 3ph. Panel ?

We have a 3-phase 480v panel close by. 


Another question 

Swapping out locations for 480V/200A spot welders for 480V/60A Water jet machines. 

Locations are already piped with 2” Emt and 3/0 copper capable of 225A. I would assume it would be ok to use this much larger wiring for 60A machinery (convert the wire to #6awg in cans using Polaris taps). Never oversized anything to this extent. 



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## Cow (Jan 16, 2008)

Yes, it is as simple as using a 2 pole breaker in a 3 phase panel to get single phase.

For your second question, what are those 3/0's connected to at the source? A 200A breaker? That could be tough to install 60A breakers in the panel if you don't have the right bus stabs to accept several smaller framed 60A breakers available.

Insulated taps can certainly be used to reduce to #6's at the load, but you need to properly protect those #6's with a suitable OCPD upstream.

One option may be to use those 3/0's to feed a panelboard close to the load and then install some 60 amp breakers in it to feed several machines.


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## WronGun (Oct 18, 2013)

Cow said:


> Yes, it is as simple as using a 2 pole breaker in a 3 phase panel to get single phase.
> 
> For your second question, what are those 3/0's connected to at the source? A 200A breaker? That could be tough to install 60A breakers in the panel if you don't have the right bus stabs to accept several smaller framed 60A breakers available.
> 
> ...




The 3/0 conductors are fed from large 480V/200A fused lever disco’s which are fed from the buss of a full 480V panel. 

My plan is to demo the disco’s and to Install a new 480v panel in order to make room for 480v 3ph OCPD’s using the existing feed. 

We would also need to install cans at both ends of the 2” pipe runs to convert/downsize the conductors 


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## Cow (Jan 16, 2008)

Just an FYI, there are also fuse reducers available to go from 200 to 60 amps:


https://www.google.com/url?sa=t&rct...Reducers.pdf&usg=AOvVaw3ARdDrhQI7S9SARtOrcfz2


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## WronGun (Oct 18, 2013)

Cow said:


> Just an FYI, there are also fuse reducers available to go from 200 to 60 amps:
> 
> 
> https://www.google.com/url?sa=t&rct...Reducers.pdf&usg=AOvVaw3ARdDrhQI7S9SARtOrcfz2




Interesting , that would make things simpler. Almost too simple 


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## WronGun (Oct 18, 2013)

Good idea , but now that I think about it the disco’s are pretty old made by Gould. Mechanisms are pretty worn down and should be updated anyways. 


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## Southeast Power (Jan 18, 2009)

I would take the opportunity to install a new panelboard with the breaker you need and a spare or two.


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## varmit (Apr 19, 2009)

Would it not be easier to pull out the 3/0 and pull in #6 or #4, than to do all of the work to make the 3/0 fit in a 60 amp disconnect? Then sell the scrap.

You could also, following tap rules, tap the 3/0 and run #6 to your disconnect, if close enough (25 feet ) and be code compliant.

Then again, any upgrade to the old existing installation is more profit for you.


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## WronGun (Oct 18, 2013)

varmit said:


> Would it not be easier to pull out the 3/0 and pull in #6 or #4, than to do all of the work to make the 3/0 fit in a 60 amp disconnect? Then sell the scrap.
> 
> 
> 
> ...




That’s what I’m thinking. I’m taking away from work and an updated install. New panel it is. 


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