200 amp service question

[Jslys13]

Recently had a 200 amp service put in my house. My question is what is the correct size aluminum wire?

 

[tyme2par4]

4/0 Aluminum is rated for 200A service

 

[Norcal]

4/0 Aluminum is rated for 200A service

Dwelling services only.

 

[Jslys13]

4/0 Aluminum is rated for 200A service

They installed 3/0. I called the county inspector he tells me it need to be 4/0, I tell him they installed 3/0 and that it passed inspection. Puts me hold, comes back and says 3/0 is ok because the cable only needs to be rated at 83% of the load. Why would you want a breaker rated for more than your cable?

 

[Jslys13]

It's an underground feed. I had the feed from the transformer to the meter base and meter base to the panel. both are 3/0 al

 

[alfredeneuman]

Puts me hold, comes back and says 3/0 is ok because the cable only needs to be rated at 83% of the load. Why would you want a breaker rated for more than your cable?

83% of 200A is 166A
Al XHHW and the like Cable is rated for 155A in the 75 degree column.
tyme2par4 is right.

The reason why you can use a less amperage wire than breaker for a residential service only is because of the diversity of the loads. You'll never run everything at once.

 

[wyliesdiesels]

It's an underground feed. I had the feed from the transformer to the meter base and meter base to the panel. both are 3/0 al

Are you referring to the PoCos underground service entrance conductors before the meter pan?

If so, they are not required to follow the NEC...

 

[mm08822]

POCO wiring not subject to NEC ampacities.

The load side of the meter is and should be 4/0 AL.

Did your contractor run 3/0 CU or AL?

 

[Jslys13]

POCO wiring not subject to NEC ampacities.

The load side of the meter is and should be 4/0 AL.

Did your contractor run 3/0 CU or AL?

The load side of the meter is 3/0 aluminum.

 

[mm08822]

They installed 3/0. I called the county inspector he tells me it need to be 4/0, I tell him they installed 3/0 and that it passed inspection. Puts me hold, comes back and says 3/0 is ok because the cable only needs to be rated at 83% of the load. Why would you want a breaker rated for more than your cable?

83% of 200A is 166A
Al XHHW and the like Cable is rated for 155A in the 75 degree column.
tyme2par4 is right.

The reason why you can use a less amperage wire than breaker for a residential service only is because of the diversity of the loads. You'll never run everything at once.

The load side of the meter is 3/0 aluminum.

Call the contractor back and tell them to replace with 4/0 AL. Did you pay in full yet?

Call county inspector back and tell him its as per Alfred/tyme2par4's posts.
Who did the inspection? They too need an education.

If anyone tells you otherwise, they don't know how to apply this rule and/or how to use the 75C column vs 90C column conductor ampacities.

In post #16 of this thread https://www.garagejournal.com/forum/showthread.php?t=429352 there is a copy of the table that used to be included in NEC. Since removed and converted into words b/c not everyone read the conditions of use.

 

[wyliesdiesels]

Do not look at the 90* column.

Its for derating purposes only

 

[mm08822]

I doubt the meterpan or cb terminations are rated for 90C. 75C I'm certain of.

Also the table you posted (sberry's 200a post) gives the service size for a given conductor size and specifies the insulation.

 

[alfredeneuman]

Correction to my above post:
I didn't look at the ampacity of 3/0 aluminum: It is rated at 155 for 75 degree rating, and 175 for 90 degree rating wire types.
So, a little more research into what type of wire was used. 83% of 200 = 166 amps. So 90 degree wire could be used for a service conductor or feeder, but a 75 degree rated wire could not.

I said the same thing way back in post #6.
90 degree wire can be used for anything, but the ratings are according to the teminations' ratings. There are no terminations on breakers with a 90 degree rating so you have to use the 75 degree column on 90 degree rated wire.

The County Inspector was wrong

 

[Jslys13]

I said the same thing way back in post #6.
90 degree wire can be used for anything, but the ratings are according to the teminations' ratings. There are no terminations on breakers with a 90 degree rating so you have to use the 75 degree column on 90 degree rated wire.

The County Inspector was wrong

Thanks. This clears some things up for me.

 

[Jslys13]

Okay, where is the 3/0 wire located?

Whether it meets code or not depends on the definition of Service Conductor in code.

The Service Conductor is defined as all wires on the line side of the service disconnect. The Service disconnect is NOT the meter, it is your main breaker.

Feeders are also covered if they feed the entire load of a dwelling; feeders are lines that run from downstream of the main disconnect to other distribution panels with overcurrent protection devices. Note that they are only covered if they feed an entire residence, not a portion of one.

So, the lines from the meter to the main breaker can be sized in accordance with section 310.15 of NEC as can lines running from your main panel to subpanels:


2014 Code Language:

310.15(B)(7) 120/240-Volt, Single-Phase Dwelling Services and Feeders. For one-family dwellings and the individual dwelling units of two-family and multifamily dwellings, service and feeder conductors supplied by a single-phase, 120/240-volt system shall be permitted be sized in accordance with 310.15(B)(7)(1) through (4).

(1) For a service rated 100 through 400 A, the service conductors supplying the entire load associated with a one-family dwelling, or the service conductors supplying the entire load associated with an individual dwelling unit in a two-family or multifamily dwelling, shall be permitted to have an ampacity not less than 83 percent of the service rating.

(2) For a feeder rated 100 through 400 A, the feeder conductors supplying the entire load associated with a one-family dwelling, or the feeder conductors supplying the entire load associated with an individual dwelling, unit in a two-family or multifamily dwelling, shall be permitted to have an ampacity not less than 83 percent of the feeder rating.




The basis of the 83% rule is it is presumed that the panel will never see full capacity when you look at the load of the entire residence as a whole.

At the new meter base has a 200 amp disconnect right below it.

 

[Jslys13]

Well good news. After talking to contractor he admitted he made a mistake and is coming back Monday to replace the cable to 4/0.

 

[wyliesdiesels]

At the new meter base has a 200 amp disconnect right below it.

Since there is a disconnect did he run 4-wire feeder to the load center/subpanel?

Well good news. After talking to contractor he admitted he made a mistake and is coming back Monday to replace the cable to 4/0.

ouch thats an expensive mistake

Now you need to file a complaint with the AHJ about the inspector

 

[Jslys13]

Since there is a disconnect did he run 4-wire feeder to the load center/subpanel?




ouch thats an expensive mistake

Now you need to file a complaint with the AHJ about the inspector

He did run 4 wire to my house panel, run 3 wire to my pole barn but inspector caught that and made him run 4 wire.

 

[wyliesdiesels]

Is this guy licensed?

 

[Mr. T]

Is this guy licensed?

If Ohio is like the great Commonwealth of Pennsylvania the answer might be that there is no such thing.

In PA you’re an electrician if you call yourself one. (With the exception of some municipalities)

 

[alfredeneuman]

If Ohio is like the great Commonwealth of Pennsylvania the answer might be that there is no such thing.

No. Ohio has a Contractors Licensing Program

 

[Jslys13]

Is this guy licensed?

He is licensed. stark county ohio requires it. He did pull permits and scheduled inspections.

 

[Jslys13]

Another question. He is replacing the cable between the meter base and transformer later this week. He already replaced the service entrance cable from meter to panel. My question is can the neutral be smaller than the hot legs going to the transformer?

 

[mm08822]

Another question. He is replacing the cable between the meter base and transformer later this week. He already replaced the service entrance cable from meter to panel. My question is can the neutral be smaller than the hot legs going to the transformer?

Two sizes smaller is very common in cables. In your case - 4/0 hots & 2/0 neutral.

Why is the electrician replacing anything past the meter out to the street??????
That is the POCO's responsibility. They also follow different ampacity requirements than set in the NEC.

Something is very wrong here!!!!!

 

[dw1]

Two sizes smaller is very common in cables. In your case - 4/0 hots & 2/0 neutral.

Why is the electrician replacing anything past the meter out to the street??????
That is the POCO's responsibility. They also follow different ampacity requirements than set in the NEC.

Something is very wrong here!!!!!

Depends on where you are I guess, we set a pull box no more than 10' from the pole, stub a 2 1/2" sweep 90* up the pole, we run the wire from this pull box back to the meter and in to the panel and hook everything up, Power Co comes and finishes pvc conduit up the pole and runs wire into pull box and makes weather proof connections.
(This is O/H to Underground) if there is a ground Xfmer there, we run wire to Xfmer and leave 3'

 

[mm08822]

Depends on where you are I guess, we set a pull box no more than 10' from the pole, stub a 2 1/2" sweep 90* up the pole, we run the wire from this pull box back to the meter and in to the panel and hook everything up, Power Co comes and finishes pvc conduit up the pole and runs wire into pull box and makes weather proof connections.
(This is O/H to Underground) if there is a ground Xfmer there, we run wire to Xfmer and leave 3'

Ok, agreed. My POCO runs from the o/h to the weatherhead
or
if u/g w/pad mount xformer - from xformer to to meter.

Until the meter is reached, it's all by POCO specified ampacities, not NEC.

 

[Jslys13]

I was told I was responsible from the transformer to meter base. It is an underground..

 

[mm08822]

I was told I was responsible from the transformer to meter base. It is an underground..

And they require 4/0 al from the transformer to meter base for 200a service?

 

[dw1]

 

[tyme2par4]

I was told I was responsible from the transformer to meter base. It is an underground..

Typically around here you are responsible for paying for the wire, but the POCO still does the install.
As long as you tell them you are installing A/C or some other high usage device, they will upgrade you to a 200A service for free.

 

[Jslys13]

All is fixed now with 4/0