masselectrician
Member
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- Mass
Would it be a violation to feed two seperate 400A discos, which in turn feed two transformers, which each have their own panel, from one three pole 800A breaker? Assuming balancing was not an issue.
Parallel Feeder to 2 Disos
- Thread starter masselectrician
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- Massachusetts
It could be done but the conductors will have to joined together at the disco end before being connected to the discos.
masselectrician
Member
- Location
- Mass
That is the question we were debating today. Do we have to bring both sets into a can, join the two runs, then tap off to each disco so that each phase from both sets come into each disco. Just wondering if anything would prevent bringing one run into each disco directly.
masselectrician
Member
- Location
- Mass
Agreed, that's what we are looking at.
- Location
- Massachusetts
You could do that only if those conductors would meet the tap rules for distance.
If the run is long and inside than no you will have to join them first.
I just recently had to tap the end of a 1600 amp feeder with a 400 and 800 fused switch, I had to buy four 7 port 750 Kcmil 'polaris' connectors to do it at just $140 per connector.
LarryFine
Master Electrician Electric Contractor Richmond VA
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- Henrico County, VA
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- Electrical Contractor
Welcome to the forum! 
No, and might be preferable. It would certainly be easier to wire.
- Location
- Massachusetts
Welcome to the forum!
No, and might be preferable.
It might be easier and it would defiantly be cheaper but likely will be a violation.
curt swartz
Electrical Contractor - San Jose, CA
- Location
- San Jose, CA
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- Electrical Contractor
Bob, I'm curious how you made the connections to the Polaris. Did you connect the lines to ports 1-4 and the loads to ports 5-7 or did you alternate line/load. I have never noticed a current rating on the connectors but always figured they were good for at least the rating of the maximum wire size. If all of the lines were connected to one end and all of the loads to the other end the middle of the connector would need to carry 1200 amps.
chris kennedy
Senior Member
- Location
- Miami Fla.
- Occupation
- 60 yr old tool twisting electrician
You will notice they are rated for 90C.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
You could do this as Gus mentioned if you can comply with the tap rule.
- Location
- Massachusetts
Yes.
No
It's funny I contemplated this same thing the night we were doing the cut over but ended up figuring the unit must be rated for what the conductors could carry.
Quite intriguing subject. If determined by bus sizing as a "guide", the cross sectional area would have to be 1.2 in? Cu to carry 1200A at any point. Line-load staggered would definitely be the better approach.
Assuming a 2x1 out, the one would best be placed in the middle hole.
Last edited:
- Location
- Massachusetts
I had seven ports, 4 IN, 3 OUT.
I also know from a months worth of recording that the entire load carried by these connector does not exceed 700 amps.
curt swartz
Electrical Contractor - San Jose, CA
- Location
- San Jose, CA
- Occupation
- Electrical Contractor
Bob, I first want to state that I wasn't stating that you did anything wrong. I have seen these connectors used this way in the past but have always questioned how they should be connected. My gut feel was to alternate. I have not seen any instructions from NSI/Polaris. I just checked Ilsco's web site since they now makes a similar connector and below are the specifications.
- Broad wire range: 750kcmil-14
- UL Listed and CSA certified for 600 volts, 90?C
- Dual rated for copper or aluminum conductor
- Cold temperature rated to -45?C
- High dielectric strength plastisol is chemical resistant
- Black cover is UV rated
- Removable port & screw plugs
- Prefilled with De-ox
- Per NEC Article 310-16 Allowable Ampacities are as follows: # 4 - 95 Amps, 1/0 - 170 Amps, 3/0 - 225 Amps, 250 - 290Amps, 350 - 350 Amps, 500 - 430 Amps, 750 - 535 Amps
- Incoming and outgoing conductors must be staggered.
- UL File E6207
...and of the three outs 2 went to one disco while one went to another... 2x1 out.
I'm sure this info makes everyone more comfortable with your use of the connectors... but staggered is still the better approach. Don't you agree?
I know you don't like to agree with me, so I'll let you slide if you don't answer
- Location
- Massachusetts
I will go with 'it would not be worse.' :grin:
Quite honestly there where instructions with the each unit and they said nothing about what is required or expected as far as ins and outs. This tells me the units are designed to accommodate worst case loading conditions.
I know you don't like to agree with me, so I'll let you slide if you don't answer
[/QUOTE]LOL:grin:
- Location
- Massachusetts
I did not take it that way.
Well thats interesting.
I have one left I will have to check what brand I have.
chris kennedy
Senior Member
- Location
- Miami Fla.
- Occupation
- 60 yr old tool twisting electrician
I will second that. But I have never seen that in my research of NSI. Bob, the taps in your picture are polaris.
curt swartz
Electrical Contractor - San Jose, CA
- Location
- San Jose, CA
- Occupation
- Electrical Contractor
How can you tell Chris?
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