480 volts 200 amp feeders in SER cable ?

Buck Parrish

Senior Member
Location
NC & IN
The GC has poured the slab on a large assisted living new constrution job. None of the 3 phase 200 amp feeders were installed under the slab as they usssually would have. There would be numerous transformers, generators , etc...
The contractor is saying to install it (480 V, 3 phase feeders) in SER cable. I never heard of that , have you?
Most of the branch circuits are to be done in romex.
I was wondering what my options are.
 

kenman215

Senior Member
Location
albany, ny
The GC has poured the slab on a large assisted living new constrution job. None of the 3 phase 200 amp feeders were installed under the slab as they usssually would have. There would be numerous transformers, generators , etc...
The contractor is saying to install it (480 V, 3 phase feeders) in SER cable. I never heard of that , have you?
Most of the branch circuits are to be done in romex.
I was wondering what my options are.
They definitely make 3 phase SER. More info is needed to answer your question though... Is this all one structure? Is there a main electrical room? Is there individual metering for each apartment?
 

kenman215

Senior Member
Location
albany, ny
Yes , thanks. It's one structure on a slab. It's all under one roof. All one meter, not individual meters.
I don't think you're really too screwed here code wise. It sounds like you're really just talking about running panel feeders from the electrical room through the structure in SER. As long as the cable is protected from other trades and run in a code compliant manner, I don't really see you getting jammed up.
 

iwire

Moderator
Staff member
Location
Massachusetts
The GC has poured the slab on a large assisted living new constrution job. None of the 3 phase 200 amp feeders were installed under the slab as they usssually would have. There would be numerous transformers, generators , etc...
The contractor is saying to install it (480 V, 3 phase feeders) in SER cable. I never heard of that , have you?
Most of the branch circuits are to be done in romex.
I was wondering what my options are.
As long as NM is allowed the entire route it is not a problem.

SER is 600 volt cable and can be used for services, feeders or branch circuits.
 

iwire

Moderator
Staff member
Location
Massachusetts
Thank, I forgot to mention, several are 400 amp. That was the big concern
Whoa, you mean they want to run two sets of 200 amp SER for a 400 amp?

If so that is a problem, that will result in a violtion of 250.122(F)

2011 NEC, sections may have changed fr 2014.

(F) Conductors in Parallel. Where conductors are installed
in parallel in multiple raceways or cables as permitted in
310.10(H), the equipment grounding conductors, where used,
shall be installed in parallel in each raceway or cable. Where
conductors are installed in parallel in the same raceway, cable,
or cable tray as permitted in 310.10(H), a single equipment
grounding conductor shall be permitted. Equipment grounding
conductors installed in cable tray shall meet the minimum
requirements of 392.10(B)(1)(c).
Each equipment grounding conductor shall be sized in
compliance with 250.122.
The EGC in a 200 amp cable is not large enough for a 400 amp feeder.
 
Whoa, you mean they want to run two sets of 200 amp SER for a 400 amp?

If so that is a problem, that will result in a violtion of 250.122(F)

2011 NEC, sections may have changed fr 2014.



The EGC in a 200 amp cable is not large enough for a 400 amp feeder.
I think you will find that this actually isn't an issue. The EGC in the cable is not minimum size, at least around here
 

Jraef

Moderator
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
...or cable tray as permitted in 310.10(H), a single equipment
grounding conductor shall be permitted. ...
I read that as OK, but not as REQUIRED. In other words if you are WANTING to run parallel power conductors on the same raceway, and WANT to run just one EGC that is sized for the total load, you are allowed to. But I don't see that as restricting you AGAINST using parallel EGCs too. Am I wrong?
 

iwire

Moderator
Staff member
Location
Massachusetts
I read that as OK, but not as REQUIRED. In other words if you are WANTING to run parallel power conductors on the same raceway, and WANT to run just one EGC that is sized for the total load, you are allowed to. But I don't see that as restricting you AGAINST using parallel EGCs too. Am I wrong?
But this is not a raceway it is a SER cable assembly 300.3(B) requires the EGC to be run with the circuit conductors and 250.122(F) requires a full size EGC in each cable.
 

kwired

Electron manager
Location
NE Nebraska
If one were going to run a metal raceway, why not run individual conductors within instead of SE cable?

A. Raceway probably can be a little smaller then if cable were pulled through it.

B. Less copper/aluminum used (likely lowering overall cost) if raceway is used as EGC.
 
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