NEC 230.2 --- one service

[Sparky32297]

It has been a common practice to run two sets of underground wire from the POCO transformer to a house that required a 400 amp service. These two sets were the service entrance conductors for two - two hundred amp panels with the main breakers serving as two service disconnects. These panels are located side by side (grouped). The two sets of service entrance conductors do not connect to each other after they leave the transformer. I am now being told that the two sets of service entrance conductors have to terminate in 400A rated equipment first and then have as many as six disconnects. (not sure what this means yet) I am guessing that the inspector is requiring a 400A disconnecting means or a junction box or a terminal box.

I assumed that the exception #2 to 230.40 covered this.

Exception No. 2: Where two to six service disconnecting
means in separate enclosures are grouped at one location
and supply separate loads from one service drop, set of
overhead service conductors, set of underground service
conductors, or service lateral, one set of service-entrance
conductors shall be permitted to supply each or several such
service equipment enclosures.

I am being told that this only applies to separate occupancies ( strip malls etc.)

Any thoughts ??

 

[Dennis Alwon]

You cannot have 2 service laterals run to the house is correct unless you have certain conditions which you do not qualify for. The exception is for malls, apartments etc where there are many apartments or tenants.

If you already ran the wire then you must use them as a parallel set and install a trough then use the tap conductor rule to feed your 2- 200 amp panels.

 

[don_resqcapt19]

You cannot have 2 service laterals run to the house is correct unless you have certain conditions which you do not qualify for. The exception is for malls, apartments etc where there are many apartments or tenants.

If you already ran the wire then you must use them as a parallel set and install a trough then use the tap conductor rule to feed your 2- 200 amp panels.

If the service point is the line side of the meter, then the service laterals are not covered by the code rules. The only way the NEC would apply to these conductors is when the service point is at the load side of the utility transformer.

 

[texie]

To the OP: If the conductors are separated from the POCO transformer the each 200 amp disconnect, how do you have one meter?

 

[Dennis Alwon]

The only way the NEC would apply to these conductors is when the service point is at the load side of the utility transformer.

If the ec is installing the lines from the transformer I understood that to be the case.

 

[kbsparky]

Are they using CT's for the metering?

 

[Sparky32297]

yes, the metering is being done by CT's. I neglected to mention that. There are other instances that POCO has a 400 amp meter by transformer with double barrel lugs on them and we have been running from their meter. The POCO's also install a grade level transfer switch with metering. No over current protection is provided.

 

[don_resqcapt19]

If the ec is installing the lines from the transformer I understood that to be the case.

It doesn't matter who installs the cables. The only thing that matters is the location of the service point. However, with the meter at the transformer, the service point is likely there too and that would make the laterals subject to the rules in the NEC.

 

[texie]

Now that I understand the metering setup the OP raises an interesting question. It would seem that as some said that this would not be compliant as the conductors are laterals. But, for sake of discussion, what if this was a CT meter (or even a self contained meter) that was mounted on the structure with the 2-200 amp disconnects next to it? Then I think this would be in compliance as the conductors from the meter to the 2 disconects are not laterals. Do I have this right?

 

[fmtjfw]

I don't see anything in exception 2 that restricts it from being applied to a single residential service.

Exception No. 2: Where two to six service disconnecting means in separate enclosures are grouped at one location and supply separate loads from one service drop, set of overhead service conductors, set of underground service conductors, or service lateral, one set of service-entrance conductors shall be permitted to supply each or several such service equipment enclosures.

100 Service-Entrance Conductors, Underground System. The service conductors between the terminals of the service equipment
and the point of connection to the service lateral or underground service conductors.

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

100 Service Point. The point of connection between the facilities of the serving utility and the premises wiring.

The definitions of conductors in a service entrance chain from the utility to the service equipment has always confused me.

OK, so we start at the POCO transformer. POCO decides to place metering at the xfrmr in the form of CTs and potential taps.
I presume this is where the service lateral ends.
Now the conductors from the CTs toward the customer are called what? I think "Service-Entrance Conductors, Underground System"
Now Exception 2 states "one set of service-entrance conductors shall be permitted to supply each or several such service equipment enclosures"

I read this to mean that one set of service-entrance conductors can supply each service equipment enclosure, another set another enclosure. If it doesn't mean this then existence of Exception 2 is meaningless. All the other exceptions allow multiple service-entrance conductors, in contrast with the general rule in 230.40 which allows only one set.

I also believe the POCO, not the NEC define the service point.

So where does it say this can't be a single dwelling?

 

[kwired]

What OP is proposing is common practice and has been done that way for years. It is not limited to dwellings or multiple occupancy buildings.

Lets go back to 230.2 and read it more carefully, in particular the second sentence.

230.2 Number of Services.
A building or other structure served shall be supplied by only one service unless permitted in 230.2(A) through (D). For the purpose of 230.40, Exception No. 2 only, 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.

That section along with 230.40 exception 2 allows allows six sets of underground conductors 1/0 and larger to originate at same place and land in six different service enclosures.

 

[texie]

What OP is proposing is common practice and has been done that way for years. It is not limited to dwellings or multiple occupancy buildings.

Lets go back to 230.2 and read it more carefully, in particular the second sentence.




That section along with 230.40 exception 2 allows allows six sets of underground conductors 1/0 and larger to originate at same place and land in six different service enclosures.

I agree with this when the meter is at/on the building and I have done many this way. My only reservation in the OP's case is that the conductors from the meter could be called laterals and possibly change the situation. Do you think that is the case? See my post #9.

 

[texie]

I agree with this when the meter is at/on the building and I have done many this way. My only reservation in the OP's case is that the conductors from the meter could be called laterals and possibly change the situation. Do you think that is the case? See my post #9.

Never mind.... after rereading the relevent code I think you are correct. It would seem that either way you do it (from my post #9) it would be compliant.

 

[hurk27]

What OP is proposing is common practice and has been done that way for years. It is not limited to dwellings or multiple occupancy buildings.

Lets go back to 230.2 and read it more carefully, in particular the second sentence.




That section along with 230.40 exception 2 allows allows six sets of underground conductors 1/0 and larger to originate at same place and land in six different service enclosures.

Correct because since the utility point ends at the lugs of the transformer (would be strange around here for a house) the conductors leaving these lugs are by NEC definition service entrance conductors and 230.40 Exception 2 covers it the same as if the meter was mounted on a pole and you ran two sets of SEC's.

Now add 230.40 Exception 3 and you could run another set to a garage or other buildings and the six disconnect rule starts all over again.

all you have to look at is the point where the utility ends and the NEC begins to know if they are SEC's or service conductors, this is the point many miss.

Look at 230.1 figure and the Box labeled "Terminal box, meter, Or other enclosure" can clearly cover the transformer as other enclosure, after this point the conductors are SEC's till they get to the service disconnect/s.

Now as for around here we run conduits to transformer pads and if the transformer has CT's at it, we split the service at that point to separate panels, if we have a CT cabinet then it is at this point we split to separate panels, I have had to show this two a few inspectors who questioned this kind of install.

 

[don_resqcapt19]

Correct because since the utility point ends at the lugs of the transformer (would be strange around here for a house) the conductors leaving these lugs are by NEC definition service entrance conductors and 230.40 Exception 2 covers it the same as if the meter was mounted on a pole and you ran two sets of SEC's.
...

I don't think those conductors are service entrance conductors under the 2011 code. If they are on the load side of the service point they would be "Service Conductors, Underground" and if they are on the line side of the service point they would be a "Service Lateral".

 

[kwired]

I have always understood that with laterals where the conductors directly enter the building without hitting a meter or splice box the "service entrance conductors" start at the point where the conductors enter the building. If the service disconnect is on the outside of the building you don't necessarily have service entrance conductors, but you do need to know what the equivelant service entrance conductors would be for sizing your grounding electrode conductor.

 

[hurk27]

I don't think those conductors are service entrance conductors under the 2011 code. If they are on the load side of the service point they would be "Service Conductors, Underground" and if they are on the line side of the service point they would be a "Service Lateral".

If this is so then how will 230.40 exception 3 ever apply where we run from the load side of a meter to another out building from a underground service? and why does there need to be such a difference between underground and over head?

I just read the new changes to the 2011 and I think the addition of the definition of "service conductors, underground" to article 100 just threw a wrench in to the works when applying many of the exceptions to 230.40?

This should not have been allowed without updating the exceptions to include this new definition.

 

[don_resqcapt19]

If this is so then how will 230.40 exception 3 ever apply where we run from the load side of a meter to another out building from a underground service? and why does there need to be such a difference between underground and over head?

I just read the new changes to the 2011 and I think the addition of the definition of "service conductors, underground" to article 100 just threw a wrench in to the works when applying many of the exceptions to 230.40?

This should not have been allowed without updating the exceptions to include this new definition.

The purpose of the change was to have different different definitions for conductors covered by the NEC and the conductors that are under the control of the utility. The service drops and service laterals are utility conductors, the "service conductors, overhead" and "service conductors, underground" are NEC conductors. The exceptions in 230.40 have been changed to include the new terms.

Exception No. 3: A single-family dwelling unit and its accessory structures shall be permitted to have one set of service-entrance conductors run to each from a single service drop, set of overhead service conductors, set of underground service conductors, or service lateral.

 

[hurk27]

The purpose of the change was to have different different definitions for conductors covered by the NEC and the conductors that are under the control of the utility. The service drops and service laterals are utility conductors, the "service conductors, overhead" and "service conductors, underground" are NEC conductors. The exceptions in 230.40 have been changed to include the new terms.

I see this now, but it now makes it non-compliant running separate runs from a transformer to each panel as has been done for years, at least that is the way I'm seeing it with the new definition?? why did we even need this definition if we understood that the NEC clearly applied after the utility point? here the utility point was either the top of the meter (underground) or the transformer load lugs if the CT's were in the transformer, after this point we always treated our side as service entrance conductors, with the new wording if we have a meter out on the pole and it goes back underground we cant use exception 2 or 3 to run from the pole to multiple panels or to the out buildings.

Exception No. 3: A single-family dwelling unit and its accessory structures shall be permitted to have one set of service-entrance conductors run to each from a single service drop, set of overhead service conductors, set of underground service conductors, or service lateral.

It is as if now we must hit the building first before these exceptions can be used, ((((WHY))))???

All this does is add cost by requiring us to run to a building first before we can run to the other building (exception 3 only)

Guess just ranting because when I see changes like this it really doesn't do anything other then making for longer runs or larger conductors, having to install a tap box at the building because the meter is out on the pole or transformer.

 

[iwire]

Exception No. 2: Where two to six service disconnecting
means in separate enclosures are grouped at one location
and supply separate loads from one service drop, set of
overhead service conductors, set of underground service
conductors, or service lateral, one set of service-entrance
conductors shall be permitted to supply each or several such
service equipment enclosures.

I am being told that this only applies to separate occupancies

All I see is separate loads, I don't see separate occupancies.