Considered one service or two services

[hhsting]

Attached sketch shows two sets of service laterals (underground) from one electric utility transformer going to each service disconnects.

Both service disconnects are grouped at the building exterior. The building has one tenant only.

One service lateral is 4#250kcmil Al and second is 4#4/0 awg Al. Service point is at the service disconnect line side terminal

I am not sure if I am allowed to have two sets of service lateral or not. Its confusing

Would NEC 2014 section 230.2 first paragraph apply here or not? Is the attached sketch considered one service or two services?:

“For the purpose of 230.40 exception no. 2 only underground sets of conductors, 1/0awg 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”

230.40 exception no.2:

“Where two to six service disconnecting means in separate enclosure are grouped at one location and supply separate loads from one service drop, set of overhead service conductors, sets of underground service conductors, or service lateral, one set of service entrance conductors shall be permitted to supply each or several such equipment enclosures

 

[augie47]

The Section you quoted allows the installation as shown.:
“For the purpose of 230.40 exception no. 2 only underground sets of conductors, 1/0awg 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”

 

[hhsting]

Correction Post#1 building has two separate tenants NOT one tenant. Each service disco serve each tenant.

The question then I have is grounding and bonding of the two service disconnects. Would it follow NEC 2014 Section 250.64(D) or 250.64(F)? The section quoted below says considered one service but actually its not one service making it confusing which section NEC 2014 section 250.64(D) or 250.64(F) apply?


“For the purpose of 230.40 exception no. 2 only underground sets of conductors, 1/0awg 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”

 

[augie47]

By definition. AGAIN you have one service with (2) service disconnects. 250.64(D) will apply

 

[hhsting]

By definition. AGAIN you have one service with (2) service disconnects. 250.64(D) will apply

So then my common grounding electrode conductor NEC 2014 section 250.64(D) would be sized incoming 2 sets of 250kcmil Al going to the service disco 1 and 4/0 Al going to the service disco 2.

Total: 500 kcmil + 212 kcmil = 712 kcmil Al

Table 250.66: 2/0 awg copper is ok?

 

[augie47]

Your calculations don't mach your sketch but you have had 250.66 questions enough that the Table shold be 2nd nature by now. 2/0 Cu is o.k.

 

[david]

So then my common grounding electrode conductor NEC 2014 section 250.64(D) would be sized incoming 2 sets of 250kcmil Al going to the service disco 1 and 4/0 Al going to the service disco 2.

Total: 500 kcmil + 212 kcmil = 712 kcmil Al

Table 250.66: 2/0 awg copper is ok?

[QUOTE="hhsting, post: 2644540, member: 157800" ] One service lateral is 4#250kcmil Al and second is 4#4/0 awg Al. Service point is at the service disconnect line side termina [/QUOTE]


Common Grounding Electrode Conductors and Taps

“……..circular mil area of the largest ungrounded conductor ……………”



From what you posted you have 250 alum to one grouped service disconnect and 4/0 alum to a second grouped service disconnect



Your larges cirl. mil area than would be 250 alum



250 alum table 250.66 would be a #4 copper or a # 2 alum



As already posted your math however does not match you post

 

[don_resqcapt19]

Service laterals are not under the control of the NEC. The utility can do what ever they want to.

 

[augie47]

Service laterals are not under the control of the NEC. The utility can do what ever they want to.

With our area POCOs if that was commercial the conductors would be customer owned, contractor installed.. It does vary by area

 

[david]

Service laterals are not under the control of the NEC. The utility can do what ever they want to.

I didn’t take the op’s question to be what the utility can install but more about grouped disconnects one with a 250-alum service lateral and a second with a 4/0 alum service lateral



If that is the case I’m not certain what difference it makes who owns the laterals. the service disconnects should be customer owned

Edit: Unless you are referring to the direction to go to 250.66 note !

 

[don_resqcapt19]

I didn’t take the op’s question to be what the utility can install but more about grouped disconnects one with a 250-alum service lateral and a second with a 4/0 alum service lateral



If that is the case I’m not certain what difference it makes who owns the laterals. the service disconnects should be customer owned

Edit: Unless you are referring to the direction to go to 250.66 note !

His post said:
" I am not sure if I am allowed to have two sets of service lateral or not. Its confusing "

 

[hhsting]

His post said:
" I am not sure if I am allowed to have two sets of service lateral or not. Its confusing "

Let me just repharse that cause I think I have service lateral but all this is on plans so not sure where service point is at the utility transformer or main service disco. Plans don’t call it out and I assumed to be at the service disco but that maybe not the case

So the question is attached sketch post #1 considered one utility service or two utility services?

 

[don_resqcapt19]

If the service point is the load end of the service laterals it is two services. If it is at the transformer, you have one.

 

[hhsting]

If the service point is the load end of the service laterals it is two services. If it is at the transformer, you have one.

If service point is at the line side terminal of the service disconnects then you are saying its two services? I have two tenants and each service lateral and service disco feed each tenant. So have to ask the designer to provide one service 230.2? One service lateral?

Would not the following make it one service:
230.2 first paragraph

“For the purpose of 230.40 exception no. 2 only underground sets of conductors, 1/0awg 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”

230.40 exception no.2:

“Where two to six service disconnecting means in separate enclosure are grouped at one location and supply separate loads from one service drop, set of overhead service conductors, sets of underground service conductors, or service lateral, one set of service entrance conductors shall be permitted to supply each or several such equipment enclosures

 

[electrofelon]

If the service point is the load end of the service laterals it is two services. If it is at the transformer, you have one.

Would not the following make it one service:
230.2 first paragraph

“For the purpose of 230.40 exception no. 2 only underground sets of conductors, 1/0awg 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”

I was about to say I agree with hhsting here. Then I reread 230.2, and its really a mess. I am not really sure what they are trying to say in 230.2. It seems like an unnecessary statement, unless they are trying to allow for "expanding" 230.40 Exception #2 to cases where there are not service entrance conductors.

 

[don_resqcapt19]

In my opinion the code has no authority over the number of services to a building...you get what the utility gives you.
The only issue I see is if there are a total of more than six disconnects at that location. If not, it really doesn't matter.

 

[electrofelon]

In my opinion the code has no authority over the number of services to a building...you get what the utility gives you.
The only issue I see is if there are a total of more than six disconnects at that location. If not, it really doesn't matter.

I am inclined to agree. Although the code tries to say you can only have one drop or lateral, its really none of their business how the POCO supplies it.

 

[hhsting]

Take a look at this especially blue text under 230.40 exception 2:

 

[electrofelon]

Take a look at this especially blue text under 230.40 exception 2:

Yes, that could be what they are trying to say in 230.2, is that you can essentially substitute multiple service laterals for the multiple sets of SEC allowed in 230.40 Ex #2. I am just not logically following their wording, but that is likely what they mean.

Note the commentary is not code, just the authors interpretation and opinion.

 

[hhsting]

Yes, that could be what they are trying to say in 230.2, is that you can essentially substitute multiple service laterals for the multiple sets of SEC allowed in 230.40 Ex #2. I am just not logically following their wording, but that is likely what they mean.

Note the commentary is not code, just the authors interpretation and opinion.

So if one is not sure if its one service or two then which grounding and bonding to follow 250.64(D) or 250.74(F)?