230.7 clarification

[mcelweec@gmail.com]

I have a service end box sandwiched between 2 switchboards. Each switchboard has a 3000 amp service switch followed by 2 cubicles with fusible disconnects. The metering is done on the load side of the fusible disconnects.
A tenant wants to add an unanticipated 800amp service , the load cannot be accommodated by either of the switchboards.
We need to do another tap from the service end box.
We can’t use the top of the end box as this is where the utility wires come in & we are not permitted to be on their side of the box.
We would prefer not to excavate if possible.
My question is can we race through the switchboard cubicles to feed the 800 amp switch.?
If this is not permissible could we create a barrier inside the cubicles ?

 

[augie47]

Are there nipples or conduits between your service box and your 3000 amp gear ?

 

[mcelweec@gmail.com]

The service end box is a cubicle section. Its bolted to both switchboard A & switchboard B with a bushed opening allowing the service conductors to pass through , similar to a trough opening.
My main concern is when we pass through the cubicle with the main switch we are going to be passing through 2 cubicles which are on the load side of the main.

 

[electrofelon]

My question is can we race through the switchboard cubicles to feed the 800 amp switch.?
If this is not permissible could we create a barrier inside the cubicles ?

I am not clear enough on the setup and arrangement to say yay or nay, but take a look at 408.3(A)(3)

Edit to add: Regarding you specific question about 230.7, a cabinet or switchboard is not a raceway.

 

[mcelweec@gmail.com]

Possibly the exception might apply.
I was thinking of running a trough to serve as a barrier running a long the bottom of the gear. There is plenty of room.
I would be installing a remote 800 amp meter combo.
BTW my setup is 7 cubicles. SEB in the middle, service disconnect with 2 branch cubicles either side.

 

[augie47]

A bit hard to visualize but it appears the install would be Code compliant.

 

[jaggedben]

You might want to confirm with the switchboard manufacturer that you're not violating their listing.

 

[mcelweec@gmail.com]

https://forums.mikeholt.com/asset.php?fid=20992&uid=102188&d=1557222030

 

[mcelweec@gmail.com]

I wasn’t sure if that was going to upload.
It’s hard to make everything out , but you’ll feel the heavy black line going to the end line box.
I want to come out the right hand side with a trans S combo to feed the new tenant.

 

[Dennis Alwon]

IMO, you can use the switchboard as a raceway for your conductors however are the conductors coming into the building large enough to handle the extra load?

 

[oldsparky52]

Trying to wrap my head around this, you are planning to tap unprotected service conductors and run through (2) cabinets to get to your OCP device? Sorry, but I can't read your drawing.

 

[oldsparky52]

When wiring gas stations, we would at times install a conduit for intrinsically safe circuits through a line voltage wiring trough to get to the other side and no inspector ever had a problem with that. I'm saying that to say if you have the room in the adjacent cabinets, I would think you could install a raceway to isolate the service conductors from the non service conductors in those adjacent cabinets.

 

[mcelweec@gmail.com]

Oldsparky52 that is correct going through 3 cabinets unprotected.
My other option is to excavate the newly poured concrete to get underneath the SEB.
Dennis Alwon , the 3000amp switches are maxed out, we need to get the additional load from the utility , they are installing a new transformer vault in the street to service the building.

 

[electrofelon]

Oldsparky52 that is correct going through 3 cabinets unprotected.
My other option is to excavate the newly poured concrete to get underneath the SEB.
Dennis Alwon , the 3000amp switches are maxed out, we need to get the additional load from the utility , they are installing a new transformer vault in the street to service the building.

Another thing you might want to check on is how much conductor they will allow per the "nearest point of entry" clause.

 

[oldsparky52]

... the 3000amp switches are maxed out, we need to get the additional load from the utility , they are installing a new transformer vault in the street to service the building.

Are the existing service conductors from the transformer to the service equipment large enough for the additional load or are you upgrading those too?