Unfused Wire / Disconnect Grouping Question

[SparkyAdam]

I am working on a project for an industrial facility with 400 amps of three-phase power (208). They want to add one 200-amp service, bringing the total to 600 amps.

Currently, the CT Can is nippled to one main breaker panel and one knife switch disconnect, which feeds a nearby main lug panel. They want to add one 200-amp panel to the current system fed from a new mast. The current CT Can is wide enough to accommodate a third nipple to either a main breaker panel or a knife switch disconnect, but on the other side of the wall, a beam prevents me from placing anything there.

Can I route a 200amp feeder from the CT Can, through the existing knife switch disconnect, to a new knife switch disconnect placed where panel 2 is now? Or would I have to remove the knife switch and panel 2, and place a gutter that would nipple to two different disconnects?






View attachment Panels.jpg

 

[SparkyAdam]

I know you can use a disconnect as a pass-through per 312.8, but 312.8A4 says you have to label its shut-off location; in this case, since the pass-through conductors are from a CT Can, there isn't one until it hits the disconnect that we would add directly adjacent.

I'm not sure why, but I'm pretty certain I cannot run a pipe from the CT Can on the exterior surface and LB it into a new disconnect on the inside. Am I wrong?

 

[electrofelon]

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I'm not sure why, but I'm pretty certain I cannot run a pipe from the CT Can on the exterior surface and LB it into a new disconnect on the inside. Am I wrong?

I think you are wrong. Do you have a code section you think it violates?

 

[electrofelon]

I also don't see an issue with two sets of service entrance conductors entering the first safety switch, with one landing on that switch and the other continuing to another safety switch.

 

[SparkyAdam]

I think you are wrong. Do you have a code section you think it violates?

I was always told you could not have unfused wire in an LB. I cannot find a code for it. It might have been that the utility company prohibited it, but in this case, if it came after the CT that might change that.

Still have to group the disconnects, but an exterior surface pipe to feed the new panel would be easier if it were allowed.

 

[electrofelon]

I was always told you could not have unfused wire in an LB. I cannot find a code for it. It might have been that the utility company prohibited it, but in this case, if it came after the CT that might change that.

Still have to group the disconnects, but an exterior surface pipe to feed the new panel would be easier if it were allowed.

There is no such code. You are correct some utilities prohibit LBs in unmetered conductors, but that would not apply in your case.

 

[SparkyAdam]

I also don't see an issue with two sets of service entrance conductors entering the first safety switch, with one landing on that switch and the other continuing to another safety switch.

Per 312.8A4, what would you label the disconnect in this case (since it cannot be shut off)

 

[texie]

The conductor marking in the photo would indicate this is a 120/240 3 phase 4 wire service, not a 208Y. Or maybe that orange looking tape is actually red.

 

[augie47]

Take note that NF switches normally have a 10K AIC rating. When you increase your service size you might find this to be an issue.

 

[SparkyAdam]

Take note that NF switches normally have a 10K AIC rating. When you increase your service size you might find this to be an issue.

The existing is a fused switch, I was likely adding a fused also, just general duty since its only 208

 

[augie47]

The existing is a fused switch, I was likely adding a fused also, just general duty since its only 208

I made an assumption on "knife switch disconnect " my bad

 

[electrofelon]

Per 312.8A4, what would you label the disconnect in this case (since it cannot be shut off)

There is certainly some poor wording and ambiguity there which has created some debate about how this applies to service conductors. My personal opinion is that the disconnect for the service entrance conductors is the service disconnecting means. Here is what part VI of article 230 says:

Part VI. Service Equipment — Disconnecting Means
230.70 General. Means shall be provided to disconnect all conductors in a building or other structure from the service entrance conductors.

I think most people jump to the conclusion that 312.8 is referring to a disconnecting means BEFORE the enclosure so that all conductors in that enclosure can be de-energized, but I do not see anything whatsoever requiring that in 312.8, thus I see the service disconnect to be the most reasonable disconnect for that label.

 

[PaulEd]

If you add another feeder to an existing pipe to a new switch is the pipe big enough to accommodate this?