[scottlee1]

I've got a simple question that maybe someone can answer, and I can't seem to locate the answer in the NEC. When a feeding a subpanel for service entrance into a residence, can se cable and bare ground be used, with the braided wire as the neutral? I think that the se can be used as the feeders, but the braided needs to be the ground, and the neutral needs to be an insulated conductor. Can someone please help me out here. An article reference would help also. Thanks scott

[tkrussell]

It takes years for pros to learn the code. It is not designed to find a simple answer quickly.

BTW the answer is yes, it does need to be insulated, and only used for neutrals.

Sub-panels are to be fed with 4 wire feeder, and SER cable is widely used.

The first basic rule comes from the NEC 2008 Edition:


250.24 (A) 5 Load Side Grounding Connections
A grounding conductor shall not be connected to normally non-current carrying metal parts of equipment, to equipment grounding conductors(s), or be reconnected to ground on the load side of the service disconnecting means except as otherwise permitted in this article.

Additional detail can be found in Section 250.32.

Good question.

[scottlee1]

It takes years for pros to learn the code. It is not designed to find a simple answer quickly.

BTW the answer is yes, it does need to be insulated, and only used for neutrals.

Sub-panels are to be fed with 4 wire feeder, and SER cable is widely used.

The first basic rule comes from the NEC 2008 Edition:


250.24 (A) 5 Load Side Grounding Connections
A grounding conductor shall not be connected to normally non-current carrying metal parts of equipment, to equipment grounding conductors(s), or be reconnected to ground on the load side of the service disconnecting means except as otherwise permitted in this article.

Additional detail can be found in Section 250.32.

Good question.

tkrussell thanks for your response, Is there any section from the nec that your aware of that actually mandates the neutral be insulated?

[tkrussell]

I did in my previous post.

If your looking for the actual words " the neutral must be insulated in a subpanel" to be written in the code, stop looking.

I already gave you the section, verbatim.

[stanfortyman]

338.10(B)(2)...



338.10 Uses Permitted.

(A) Service-Entrance Conductors. Service-entrance cable shall be permitted to be used as service-entrance conductors and shall be installed in accordance with 230.6, 230.7, and Parts II, III, and IV of Article 230.

(B) Branch Circuits or Feeders.

(1) Grounded Conductor Insulated. Type SE service-entrance cables shall be permitted in wiring systems where all of the circuit conductors of the cable are of the thermoset or thermoplastic type.
Section 338.10(B)(1) was updated for the 2008 Code by changing the type of insulation from rubber to thermoset.
Branch circuits using service-entrance cable as a wiring method are permitted only if all circuit conductors within the cable are fully insulated according to 310.13. The equipment grounding conductor is the only conductor permitted to be bare or covered within service-entrance cable used for branch circuits.

(2) Grounded Conductor Not Insulated. Type SE service-entrance cable shall be permitted for use where the insulated conductors are used for circuit wiring and the uninsulated conductor is used only for equipment grounding purposes.

Exception: Uninsulated conductors shall be permitted as a grounded conductor in accordance with 250.32 and 250.140 where the uninsulated grounded conductor of the cable originates in service equipment, and 225.30 through 225.40.

[scottlee1]

Stanforty and TKR, I really appreciate the help, I just took on a position as a building inspector. I see a lot of sub fed homes wired with the braided being the neutral. It didn't look right to me so therefore I was asking. Your responses have helped and will give me the information and references I need to back it up

[tkrussell]

Glad to be of help. I am also glad Stan picked up on what you were asking about, the neutral conductor. I thought you were still hung up on the neutral bar.

Knowing your situation being an inspector, and using all the proper terms, will help in getting better answers.

The issue is to know where the Main Service Disconnecting Means (AKA Main Breaker) is located. The neutral is treated differently on the Line Side as opposed to the Load Side.

[scottlee1]

TKRussell, The disconnecting means is located beneath the meter usually in the form of a panel box or disconnect. The sub fed panel is usually 20-30 away and a 4 wire system is used to sub feed the panel. The ground and neutral bars are bonded together in the main panel and isolated in the sub fed box. I think and makes sense to me that the neutral (braided conductors) of SE cable can be used in the connections between the meter and the main disconnecting means. But from the main disconnecting means to the sub fed panel, the neutral would need to be insulated. I think that the above responses have confirmed my thinking there. It is also my understanding in reading some of Stanfortyman's references that the ground can be bare. Is this correct. Again sorry to seeming ask the same questions over and over, but I'm not as comfortable with my knowledge of the NEC as you guys are. Thx again for the help
Scott

[scottlee1]

I should have said that typically what we see is the disconnecting means being located beneath the meter... I'm sure you already knew that sorry

[tkrussell]

No problem, keep asking questions, that's what we are here for.

Hmmmm... Stan... Strat... everyone... maybe we can build our own inspector??

Sorry, was caught up in a moment.

OK, quick lesson in Code-ese. Words are literal with the code, or have very specific terms and definitions. See Article 100 Definitions. Very important. Code 101.

Mis-using words, esp about the "ground", can be confusing, and cause confusion, esp since most electricians, hopefully know the true meanings, and can bamboozle you.

A neutral is the Grounded conductor. The bare wire between a meter and a Main is a Grounded conductor, but on the Line Side of the main, and can be bare.

On the Load Side of main, the Grounded conductor shall be insulated. It cannot come in contact with the Equipment Grounding Conductor, which connects to all metal raceway, panel boxes, junction boxes, all exposed non-current carrying metal and conductors.

Note I stated... Equipment Grounding Conductor, this is the bare or green "ground".

Only at the Main shall the grounded (neutral), the equipment grounding conductor, and the grounding electrode conductor be connected, with very few specific exceptions.

The grounding electrode conductor is the wire connecting the "Neutral" to ground by a metal water line and/or ground rods. This can be bare or insulated, does need physical protection where needed, and, by the way, does not need to be marked green. ( I love arguing with inspectors about this.)

Hope this helps.