Taps

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hhsting

Senior Member
Location
Glen bunie, md, us
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Junior plan reviewer
I have incoming service conductors 4 sets of 600 kcmil to 1600 amps service disconnect.

The load side of service disconnect 4 sets of 600 kcmil feeds trough from which they are tapped to five disconnects for five different tenants all less than 10 feet from the trough.

First disconnect: 4#3/0 Awg and #6 Awg ground tapped to 200A disconnect.

Other three disconnects: 2 sets of 3/0awg and #3 Awg ground tapped to 400A disconnects.

I read somewhere parallel feeders have to be terminated at both ends but not sure about above case. Since I have parallel feeders which are tapped, would the above be allowed per code?
 

david luchini

Moderator
Staff member
Location
Connecticut
Occupation
Engineer
I have incoming service conductors 4 sets of 600 kcmil to 1600 amps service disconnect.

The load side of service disconnect 4 sets of 600 kcmil feeds trough from which they are tapped to five disconnects for five different tenants all less than 10 feet from the trough.

First disconnect: 4#3/0 Awg and #6 Awg ground tapped to 200A disconnect.

Other three disconnects: 2 sets of 3/0awg and #3 Awg ground tapped to 400A disconnects.

I read somewhere parallel feeders have to be terminated at both ends but not sure about above case. Since I have parallel feeders which are tapped, would the above be allowed per code?

Each set of tap conductors should connect to all 4 of the parallel feeder sets.

Also, I don't have the Code available, but the tap ground conductors appear undersized.
 

tkb

Senior Member
Location
MA
You will have to tap each of the parallels in each set for your new feeders.
Since 1/0 is the minimum size for parallel, the smallest tap feeder you can have is four sets of 1/0 for a 600 amp feeder.
 

hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
I do not have any 600 amps feeders. I have one 200 amps and four 400 amps feeder. So the tap is not possible since smallest is 1/0 awg four sets 600 amps feeder?

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kwired

Electron manager
Location
NE Nebraska
Does the trough feed anything but the mentioned tenant disconnects? Are they adjacent to the 1600 amp service disconnect?

If no to first question and yes to second - would probably cost you less to just connect "feeder taps" to the 1600 amp service disconnect then it will to make a proper 1600 amp conductor out of paralleled conductors and tap to it.

If you need provisions for possibly adding more down the road a switchboard or I-line panel might be worth consideration.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
As kwired stated you could just connect the 4 tap conductors directly to the 1600 amp disconnect and forget the parallel 600's, otherwise each tap has to connect to all 4 parallel sets.
 

retirede

Senior Member
Location
Illinois
Could one not consider each set of 600s taps themselves and not feeders (not paralleled)? If so, you are simply downsizing the tap conductors and only need to connect to one of the 600s for each.
I really don’t know if this is proper, thought I’d throw it out there.
 

kwired

Electron manager
Location
NE Nebraska
Could one not consider each set of 600s taps themselves and not feeders (not paralleled)? If so, you are simply downsizing the tap conductors and only need to connect to one of the 600s for each.
I really don’t know if this is proper, thought I’d throw it out there.
Technically if you went from a 1600 amp OCPD to a 600 KCMIL then to a 3/0 AWG - you are "tapping a tap". All the tap rules state the tap conductor must end at an overcurrent protective device, so the 600 KCMIL tap is what is not in compliance as it ends at another tap.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Technically if you went from a 1600 amp OCPD to a 600 KCMIL then to a 3/0 AWG - you are "tapping a tap". All the tap rules state the tap conductor must end at an overcurrent protective device, so the 600 KCMIL tap is what is not in compliance as it ends at another tap.

Agreed, otherwise just run one set of the 600's to each disconnect and you're done. :)
 

kwired

Electron manager
Location
NE Nebraska
Agreed, otherwise just run one set of the 600's to each disconnect and you're done. :)
600's may not fit so well in the 200 amp disconnect that was mentioned;) they are feeder taps either way but there is minimum size on the tap depending on whether you can apply 10 foot rule or 25 foot rule, 3/0 is too small for 25 foot rule on 1600 amps but will work with 10 foot rule.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
600's may not fit so well in the 200 amp disconnect that was mentioned;) they are feeder taps either way but there is minimum size on the tap depending on whether you can apply 10 foot rule or 25 foot rule, 3/0 is too small for 25 foot rule on 1600 amps but will work with 10 foot rule.

Yes there are many ways to do this without installing 15 or 20 Polaris style taps in the wireway.
 

kwired

Electron manager
Location
NE Nebraska
If designing this from scratch, lesser expensive way is to make each of the mentioned tenant disconnects a service disconnecting means. Sounds like they are all grouped together already - then you have no feeder tap rules, no 1600 amp disconnect. Each service disconnect can be supplied with 200 or 400 amp conductors and not worry about tap rules, and really wouldn't even need to worry about paralleling and connecting 600's either. But if supplying 5 disconnects from 4 -600's you about have to make the 600's parallel and that involves more/bigger splicing devices and enclosures to do it in.
 

hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
I am not sure how 4 sets of 600kcmil tap to 200 amp feeder and four 400amp feeder would work. Looking at instruction dont see which side is incoming, outgoing to other discos and tap.

Also brining the 200amps feeder cables and four 400 amps feeder.cables to main service disco where would they be tap to the load side of the main service disco? Do they have something like that for 1600 amps?



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infinity

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Location
New Jersey
Occupation
Journeyman Electrician
I am not sure how 4 sets of 600kcmil tap to 200 amp feeder and four 400amp feeder would work. Looking at instruction dont see which side is incoming, outgoing to other discos and tap.

Also brining the 200amps feeder cables and four 400 amps feeder.cables to main service disco where would they be tap to the load side of the main service disco? Do they have something like that for 1600 amps?

That was my suggestion and is incorrect. I thought that there were only 4 disconnects but now I see that there are actually five. My apologies, disregard that suggestion. :ashamed1:
 

hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
Would it be per code to have the 4 sets of 600 kcmil land on buses A, B, C inside trough one bus for each phase and then tap from the buses 200 amp feeder and 4 400 amps feeder to the disconnects?

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kwired

Electron manager
Location
NE Nebraska
Would it be per code to have the 4 sets of 600 kcmil land on buses A, B, C inside trough one bus for each phase and then tap from the buses 200 amp feeder and 4 400 amps feeder to the disconnects?

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bus would need to have 1600 ampacity, but I think would be fine.

Think you might want to look at switchboard pricing, especially if you don't have any gear already. I line panel maybe a good option though I think they only go up to 1200 amps. Would take up less space and probably easier to assemble and cost less in the long run.
 
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