Please Help with CT and Service

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shermansfather

shermansfather

Member
Location
Northeast Ohio
I have a job that involves providing 277/480 for future use to gravel boats. The boats will not be in place for some time, but the service needs to be installed now as the POCO is for a limited time providing the transformer free.

My parameters:
A: Load - Anywhere between 5kw and 100kw per disconnect (x2), maybe peaks of 200kw
B: Connections to disconnect made by ship's electrician, who I'm told keep rated cable, fuses and fuse reducers. I'm to leave fuses out of disconnect after my installation.
C: I'm installing 2 400 A Discos, but POCO is requiring 1600A capacity out of the vault and 1600A CT cabinet.
D: Everything is outdoors, no stucture anywhere

My questions:
A: Before the CT cabinet do I parallel the phases individually (like my drawing), the POCO is telling me to do it his way.

B. Do I bond the neutral to the EGC and electrodes at the CT cabinet or at each disconnect ? I left this off the drawing for now.

C. Would I need a main disconnect before the 2 400A discos (POCO says they usually want a disco before CT's above 800A, their engineer says he'll let it go)

D. Does anybody have any better ideas ?

Flats.jpg
 
ohmhead

ohmhead

Senior Member
Location
ORLANDO FLA
shermansfather said:
I have a job that involves providing 277/480 for future use to gravel boats. The boats will not be in place for some time, but the service needs to be installed now as the POCO is for a limited time providing the transformer free.

My parameters:
A: Load - Anywhere between 5kw and 100kw per disconnect (x2), maybe peaks of 200kw
B: Connections to disconnect made by ship's electrician, who I'm told keep rated cable, fuses and fuse reducers. I'm to leave fuses out of disconnect after my installation.
C: I'm installing 2 400 A Discos, but POCO is requiring 1600A capacity out of the vault and 1600A CT cabinet.
D: Everything is outdoors, no stucture anywhere

My questions:
A: Before the CT cabinet do I parallel the phases individually (like my drawing), the POCO is telling me to do it his way. DO IT THERE WAY




B. Do I bond the neutral to the EGC and electrodes at the CT cabinet or at each disconnect ? I left this off the drawing for now AT DISCOS



C. Would I need a main disconnect before the 2 400A discos (POCO says they usually want a disco before CT's above 800A, their engineer says he'll let it go) ID ASK AGAIN !

D. Does anybody have any better ideas ? NO IT LOOKS FINE ! BUT QUESTION WHAT PROGRAM DO YOU USE FOR YOUR LAYOUTS I LIKE THAT .

Flats.jpg
Click to expand...


i like the view and the basic design its a clean looking drawning so whats the program ?
 
augie47

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
In answer to your questions
1.Local POCOs won't accept all phases in one conduit, but if it's agreeable with your POCO it makes for a net job.
2."Normal" here is to ground the CT cabinet by the neutral connections (non-isolated)
3.Be thankful POCO doesn't want the disconnect.
4."Normal" here would be a GEC from each disconnect to the electrode(s)
 
busman

busman

Senior Member
Location
Northern Virginia
Occupation
Master Electrician / Electrical Engineer
I would have said you need one of each phase and the neutral in each conduit for the parallel, unless it's a non-metallic CT cabinet.

Mark
 
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