Re-Routing Service Entrance Conductors

[bradbb2005]

We are moving into a new office building which we are designing the layout, systems, etc. The current configuration is parallel 2 1/4" conduits underground with 4-3/0 conductors stubbing up through the existing concrete floor feeding two separate 200A panels next to each other. The conductors are metered via CTs but are our responsibility from the pole. We are attempting to NOT run new conductors.

In my design, I was calling for the conduit to be cut back outside, routed to the side of the exterior, spliced and routed inside directly to the electrical room to the main panel (main disconnect), utilizing the parallel feeds for a 400AF/350AT Main panel.

We have had two electricians tell us this is not worth trying to do, one not giving a reason and one proposing to add a 90 to the stubbed conduit and re-route the conductors outside to a JBox, splice and run as designed. I have doubts about getting that approved and the architect won't be happy.

I am wanting to get a consensus from those in the field about a design that would facilitate a constructable product. I feel it should be more simple than what it is being made out to be. See attached images for clarity.

 

[tom baker]

Are you proposing to splice service entrance conductors?
The junction box, is it after the CT cabinet?

 

[electrofelon]

So you want to abandon the existing location of the electrical gear and reroute it to a different place? I dont see any issue with intercepting the conduits outside and reworking them. You will need a service disconnect on the outside or immediately on the inside, unless you can encase the conduits in concrete.

 

[electrofelon]

Are you proposing to splice service entrance conductors?
The junction box, is it after the CT cabinet?

Yeah where are the CT's?

 

[augie47]

So you want to abandon the existing location of the electrical gear and reroute it to a different place? I dont see any issue with intercepting the conduits outside and reworking them. You will need a service disconnect on the outside or immediately on the inside, unless you can encase the conduits in concrete.

From you drawing, thats then only problem I see..

 

[tom baker]

I agree with Augie. Put 90s on the end of the existing UG conduit, turn up and hit a disconnect. Disconnects are your friend, in this case once the inspection is done, the power can be turned on and off as required.
One issue is the length of the unfused SE conductors shown in blue. The existing in red is OK as the length of the unfused SE conductors is short, and how far this can be varies with the local rules.

 

[bradbb2005]

Thanks for the replies.

I want to clarify, we are demolishing back to where the blue intercepts the red, there will only be the two conduits coming to the building, at the point the blue comes in. We would splice in a JBox on the exterior with SE-rated hardware.

Also, CTs are at the pole, just before where utility splice occurs, our responsibility takes a trip through the Weatherhead and down the pipe.

I am curious about 230.70(A)(1), " nearest the point of entrance of the service conductors ". To me, without having a ton of in-depth experience (we typically do renovations with existing services), this is kind of a vague and subjective statement. tom baker seems to support this, what is "nearest"? Nearest does not show up in Article 100 and I would fathom it is highly subjective when dealing with an AHJ. My senses tell me that running halfway across this building may be a no-go? As always, budget is a driving factor.

I guess my biggest question was answered, the reworking of the conduit outside should not be a problem.

 

[Greentagger]

2 1/4” conduits?; What did I miss?

 

[Dell3c]

2 1/4” conduits?; What did I miss?

LOL.. you didn't miss anything... .obviously conduit outside "OD"..

 

[bradbb2005]

2 1/4” conduits?; What did I miss?

Good Catch. Late in the day not sure what I was thinking, I also misrepresented the wire - 2/0 in 2".

But this post:

https://forums.mikeholt.com/threads/service-conductors-inside-a-building.145552/

was entertaining and helpful. Seems to be a long shot putting the conductors unprotected that far. We will include a disconnect on the exterior and avoid the splice altogether.

 

[electrofelon]

We will include a disconnect on the exterior and avoid the splice altogether.

Yeah I would try to avoid a splice. You can probably dig up a bit past where the disconnect will be and cut it there leaving them long enough to make it to the new disco.

Yes "nearest point of entry" is vague. Typically this means not much more than a few feet or so in my experience. Washington state specifically defines it has 15 feet which is way longer than anywhere else I have worked.

 

[augie47]

Yeah I would try to avoid a splice. You can probably dig up a bit past where the disconnect will be and cut it there leaving them long enough to make it to the new disco.

Yes "nearest point of entry" is vague. Typically this means not much more than a few feet or so in my experience. Washington state specifically defines it has 15 feet which is way longer than anywhere else I have worked.

We say 3'.... obviously it is subjective.. your AHJ has a number I'm sure.

 

[electrofelon]

We say 3'.... obviously it is subjective.. your AHJ has a number I'm sure.

Here in central NY, its all third party electrical inspections, so you may get a different answer from different inspectors, but I had one tell me once: "5 feet is the max, but you're going to have to give me a hell of a good reason why you needed 5 feet!"

 

[Greentagger]

Wasn’t sure of abbreviation 350AT? Guess thats what your main is fused at as noted 2/0 now instead of 3/0?

 

[electrofelon]

Wasn’t sure of abbreviation 350AT? Guess thats what your main is fused at as noted 2/0 now instead of 3/0?

"AT" is amp trip, and "AF" is amp frame. It is a common callout for adjustable trip circuit breakers, but I guess it works for fused switches too.

 

[ritelec]

"We are attempting to NOT run new conductors."

Is that rigid from the pole to the building?
Yeah right... piece of cake to reroute them.....

Good luck with that.

 

[Greentagger]

"AT" is amp trip, and "AF" is amp frame. It is a common callout for adjustable trip circuit breakers, but I guess it works for fused switches too.

Thanks.

 

[electrofelon]

"We are attempting to NOT run new conductors."

Is that rigid from the pole to the building?
Yeah right... piece of cake to reroute them.....

Good luck with that.

It is doable without great difficulty. Un-thread at a coupling, use threadless couplings and/or a box or C condulet.

 

[bradbb2005]

Thanks.

I didn't feel like typing all of the particulars and knew the point would be clear. It will be a 400A panel with a 350A main breaker fed by parallel 2/0.

It is doable without great difficulty. Un-thread at a coupling, use threadless couplings and/or a box or C condulet.

The latest EC we talked to seemed to have no issue with it, they also have contacts with a local utility that do this stuff all the time, so, we press on.

 

[Frank Licata]

2 1/4” conduits?; What did I miss?

... must be a special order, along with the 1-3/4" ;-)