600 and 400 amp services in same room

[Squiggy969]

Space has an existing 600 amp service 480 volt, engineer wants to add another 400 amp 480 volt service next to the existing 600 amp service from the same pad mount transformer. I told him he does not meet any of the exceptions in the NEC to allow multiple services in the same space. Usually the service would be upgraded from 600 to 1000 amps but it is easier and cheaper to just add the 400 amp. Am I missing something?

 

[augie47]

Looks like it might fit 230.2/230.40 Exception 2

 

[Squiggy969]

230.2 allows it but 230.40 exception 2 states as long as its from ONE drop or lateral. There will now be 2 separate runs from the transformer to the electrical room. I dont see it as a dangerous situation but maybe not 100% code compliant.

 

[augie47]

I fail to see the ONE drop restriction:
underground sets of conductors, 1/0 AWG and larger, running to the same location and connected together at their supply end but not connected together at their load end shall be considered to be supplying one service
From that wording, it appears to me he has two grouped service disconnects fed by more than 1 underground lateral fed from the same point thus one service.

 

[electrofelon]

I fail to see the ONE drop restriction:
underground sets of conductors, 1/0 AWG and larger, running to the same location and connected together at their supply end but not connected together at their load end shall be considered to be supplying one service
From that wording, it appears to me he has two grouped service disconnects fed by more than 1 underground lateral fed from the same point thus one service.

Yup I concur OP's setup is fine, done all the time. You can even throw in a rhyme

 

[Squiggy969]

230.40 exception 2.
"Where two to six service disconnecting means in separate enclosures are grouped at one location and supply separate loads from ONE service drop or lateral, one set of service entrance conductors shall be permitted to supply each or several such service equipment enclosures." The power is coming from one common pad mount but 2 sets of laterals. Maybe i am getting mixed up by what a lateral is considered per NEC?

Service lateral def:
a service lateral consists of the underground service conductors between the street main and the first point of connection to the service entrance conductors in a terminal box, meter or other enclosure. Where thee is no terminal box, meter or other enclosure, the point of connection shall be the point of entrance of the service conductors.

 

[petersonra]

Service lateral def:
a service lateral consists of the underground service conductors between the street main and the first point of connection to the service entrance conductors in a terminal box, meter or other enclosure. Where thee is no terminal box, meter or other enclosure, the point of connection shall be the point of entrance of the service conductors.

I looked in the code and found this definition. But I am looking in the 2017 version. maybe it has changed.

Service Lateral. The underground conductors between the
utility electric supply system and the service point.

Where is the service point on this installation?

 

[Squiggy969]

100 feet away from the pad mount transformer inside an electrical room. So according to the definition in the 2017 there would now be 2 laterals about 15 feet apart from each other but landed in the same room. One tenant

 

[electrofelon]

I am guessing the service point is at the secondary of the transformer. If it was elsewhere then typically there would be a hand hole or other box. If there is a service point after that transformer, well then really I don't really care what the NEC says how the power company serves you is their business and you have no say.

 

[Squiggy969]

Power from transformer directly to the tenant MDP. Utility is not involved after the primary side of the padmount. All under one meter, one tenant
No overcurrent protection (hi volt switch) in between, no splice points/hand holes in between

 

[electrofelon]

100 feet away from the pad mount transformer inside an electrical room. So according to the definition in the 2017 there would now be 2 laterals about 15 feet apart from each other but landed in the same room. One tenant

Ok well that doesn't sound totally in line with what 230.40 ex 2 says, but if you look at what 230.2 says (post #4) it seems fine.