Tap Box Size Calculation
- Thread starter anbm
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- Logan, Utah
How about the engineer giving it a shot first, then we electricians will check it out.
Chris
Chris
How's about this?
Engineering solution: add notes on drawing something like this:
1. Electrical contractor to install underground tap box with xxx wires in ??? conduits come in, yyy wire come out in ??? conduits, straight run, field verifaction (-:
2. Electrical contractor to install 1,600A tap box.
Just kidding, looking for quick answer from your field, trade experience...
Engineering solution: add notes on drawing something like this:
1. Electrical contractor to install underground tap box with xxx wires in ??? conduits come in, yyy wire come out in ??? conduits, straight run, field verifaction (-:
2. Electrical contractor to install 1,600A tap box.
Just kidding, looking for quick answer from your field, trade experience...
sounds like S.O.P. engineer guesses and poor ole electrician has to size
You don't mention number of wires to a set or insulation type, so one would have to guess at your conduit size. You don;t mention if it's straight pull or angle, nor if the conduits are in the same row.
Other than that, we have all we need
Using a lot of gestimatimng, roughly a 16 x 30, but if "size matters" you need to give a lot more detail and maybe a "consultation" credit card #
You don't mention number of wires to a set or insulation type, so one would have to guess at your conduit size. You don;t mention if it's straight pull or angle, nor if the conduits are in the same row.
Other than that, we have all we need
Using a lot of gestimatimng, roughly a 16 x 30, but if "size matters" you need to give a lot more detail and maybe a "consultation" credit card #
To be honest, this is wiring from secondary of a utility xfmr, the power company does not provide us the larger xfmr that we wanted. So, on secondary of their xfmr they will run a wireway -36" long hold (4) 3/0 copper to our tap box and from output of this tap box, we run (4) 4"C - each conduit has 600kCM to our main gear inside the building.
I assume we will have (2) rows of (2) 4" conduits come out of tap box, starigh run to the main gear.
Consultant credit card because of sizing wrong tap box???....That's why we need to blame on electrician to size and install the box (-:
I assume we will have (2) rows of (2) 4" conduits come out of tap box, starigh run to the main gear.
Consultant credit card because of sizing wrong tap box???....That's why we need to blame on electrician to size and install the box (-:
I'd like to think I had a simple answer.
To start with there are opinions as to ALL Art 314 rules apply in these situations. If so, and if you are coming in straight across from the wireway
it would seem that dimension would be 36" (4 x 8 +4)and the width would be whatever was necessary for your conduits.
90% of the situations I have seen like this the "taps" came in the bottom of the box across from a removable cover (often a quazite box) in which case we could go back to 312.6(A) and you would just need a 12" deep box approx. 18" sq based on the 4 sets of 4/0's
Definitely a good situation for an engineer.
To start with there are opinions as to ALL Art 314 rules apply in these situations. If so, and if you are coming in straight across from the wireway
it would seem that dimension would be 36" (4 x 8 +4)and the width would be whatever was necessary for your conduits.
90% of the situations I have seen like this the "taps" came in the bottom of the box across from a removable cover (often a quazite box) in which case we could go back to 312.6(A) and you would just need a 12" deep box approx. 18" sq based on the 4 sets of 4/0's
Definitely a good situation for an engineer.
OK this info comes with a non refundable deposit. If this is a wireway and the conduits come in one end and out the other end, and your using the tap blocks to change wire size, the dimentions of table 312.6B per article 376.56B require 16" of length to the tap blocks. If your staggering the tap blocks, you'll need 16" from the end of the wireway to the first block on the 600 kcmil side and 8" on the 3/0 awg side. 32" would be the minimum size to start with based on 314.28A1 per article 376.23B. I see a minimum 36" wireway withh minimum staggering between blocks.
Of course this is all based on what i think you are doing and using.
Rick
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