commercial service conductors are incorrect

[sgreany]

I am constantly running into 200a commercial services that the original installer used 4/0 alluminum as the service conductor. I am not going to quote the code here but we all should know that we can not install wiring tthat is supplied by wiring that contains code violations as we become liable for the existing wiring we attaced to. Therefore the way I see it I can not do any wiring on the premis if the service is in violation. Do you agree? Also I would like to know why the electrical inspectors are passing these 200a commercial services using 4/0 al. When the required wire size is 250mcm al. I certainly am not the smartest guy in the trade and I am open to being factually corrected (that includes my bad spelling and grammer skills)

 

[iwire]

Please take a look at rule 3 and 4 in the front of your Mass amendments.

You are free to ignore the existing violation.

 

[augie47]

When "several inspectors pass it", you might conclude that your interpretation could just possibly be incorrect.
Unless Mass has a regulation beyond the NEC...............
In most case 4/0AL can be used at it's 180 amp rating. 240.4(B) allows an increase to the "next larger size overcurrent device" for 800 amps or less situations.

If the calculated load iis not greater than the conductor ampacity, in this case 180 amps, you can, by Code, install a "next size up" device, in this case a 200.

250 AL might be warranted, but in a competitive situation, 4/0 might be chosen.

 

[GoldDigger]

... I am open to being factually corrected (that includes my bad spelling and grammer skills)

OK: "grammar"
You "mispelled" it.

 

[LEO2854]

I am constantly running into 200a commercial services that the original installer used 4/0 alluminum as the service conductor. I am not going to quote the code here but we all should know that we can not install wiring tthat is supplied by wiring that contains code violations as we become liable for the existing wiring we attaced to. Therefore the way I see it I can not do any wiring on the premis if the service is in violation. Do you agree? Also I would like to know why the electrical inspectors are passing these 200a commercial services using 4/0 al. When the required wire size is 250mcm al. I certainly am not the smartest guy in the trade and I am open to being factually corrected (that includes my bad spelling and grammer skills)

Because the electrical inspectors never take a good look at the wire.

Just by working there does not make you liable for the work that has been done by others.

 

[steve66]

Around here, the utility normally provides the service conductors. They size the conductors per their rules and regulations and they don't have to comply with the NEC.

They do enough of these that they know what they are doing. They aren't going to install something that is dangerous.

 

[infinity]

As Augie stated this might not be a violation at all. Do you have more information to say whether or not they could comply with what Augie said in post #3?

 

[sparkyrick]

I am constantly running into 200a commercial services that the original installer used 4/0 alluminum as the service conductor. I am not going to quote the code here but we all should know that we can not install wiring tthat is supplied by wiring that contains code violations as we become liable for the existing wiring we attaced to. Therefore the way I see it I can not do any wiring on the premis if the service is in violation. Do you agree? Also I would like to know why the electrical inspectors are passing these 200a commercial services using 4/0 al. When the required wire size is 250mcm al. I certainly am not the smartest guy in the trade and I am open to being factually corrected (that includes my bad spelling and grammer skills)

4/0 AL is acceptable for a 200A service. Please provide your code reference to say otherwise.

 

[electrofelon]

I am constantly running into 200a commercial services that the original installer used 4/0 alluminum as the service conductor. I am not going to quote the code here but we all should know that we can not install wiring tthat is supplied by wiring that contains code violations as we become liable for the existing wiring we attaced to. Therefore the way I see it I can not do any wiring on the premis if the service is in violation. Do you agree? Also I would like to know why the electrical inspectors are passing these 200a commercial services using 4/0 al. When the required wire size is 250mcm al. I certainly am not the smartest guy in the trade and I am open to being factually corrected (that includes my bad spelling and grammer skills)

As others have said that can be compliant. I work mostly in rural central NY and find that 310.15(B)(6) is frequently used for everything. Welcome to the construction trades. But that is really not so bad, Just found out today an 800 amp service fed with two parallel #1 Cu passed and will be hooked up by the utility any day now.

 

[hurk27]

As others have said that can be compliant. I work mostly in rural central NY and find that 310.15(B)(6) is frequently used for everything. Welcome to the construction trades. But that is really not so bad, Just found out today an 800 amp service fed with two parallel #1 Cu passed and will be hooked up by the utility any day now.

Are you saying 1AWG or 1/0??

If 1awg is true, it is not only a violation of 310.4, but feeding a 800 amp service with it would require a calculated load of less then 260 amps and still be a violation of 230.90 even if 1/0 was used, why would this have ever got passed??? I would have flagged this at least to the owner if not the inspector, as this is a fire waiting to happen.

All I have to say is WOW:blink:

 

[hurk27]

I am constantly running into 200a commercial services that the original installer used 4/0 aluminum as the service conductor. I am not going to quote the code here but we all should know that we can not install wiring that is supplied by wiring that contains code violations as we become liable for the existing wiring we attached to. Therefore the way I see it I can not do any wiring on the premise if the service is in violation. Do you agree? Also I would like to know why the electrical inspectors are passing these 200a commercial services using 4/0 al. When the required wire size is 250mcm al. I certainly am not the smartest guy in the trade and I am open to being factually corrected (that includes my bad spelling and grammar skills)

I agree with the others, and would add to your list at the bottom that you have a slight lack of some code knowledge, as 230.90(A) Exception 2 allows you use the next size up rule in 240.4(B) with the exception that the calculated load is below the conductors Ampacity.

 

[texie]

I agree with the others, and would add to your list at the bottom that you have a slight lack of some code knowledge, as 230.90(A) Exception 2 allows you use the next size up rule in 240.4(B) with the exception that the calculated load is below the conductors Ampacity.

Of course, you and the others are correct.
But to the OP, we are not trying to beat up on you. Just pointing out the facts. Please don't let this scare you off-welcome to the Forum.

 

[sgreany]

ok great I see were 4/0 al under 75 column is 180 and we can go the next size up. I could see if the breaker had 60 degree terminations there could be a problem. Thanks this was very helpfull.

 

[GoldDigger]

ok great I see were 4/0 al under 75 column is 180 and we can go the next size up. I could see if the breaker had 60 degree terminations there could be a problem. Thanks this was very helpfull.

Don't forget the exception mentioned to use an entirely different table for POCO service wiring, which may be what is really relevant to the installations you are looking at.

 

[sgreany]

Don't forget the exception mentioned to use an entirely different table for POCO service wiring, which may be what is really relevant to the installations you are looking at.

Please explain POCO.

 

[sgreany]

I must admit it was an inspector that told me we could not use 4/0 for a commercial service and I guess I should have looked it up as I usually do. I guess I owe a guy an appoliagy.

 

[GoldDigger]

I must admit it was an inspector that told me we could not use 4/0 for a commercial service and I guess I should have looked it up as I usually do. I guess I owe a guy an appoliagy.

An easy enough mistake if you are used to seeing SE conductors sized by NEC 310.15(B)(6), and do not notice that it specifically refers to a dwelling unit.
If you can justify the 4/0 Al by other calculations, that would apply to commercial too.

 

[sgreany]

Ok so im looking deeper into it and what I found is that under 310.15 (b)(7) for 100a residential service I can use 2 al. 310.15 says 2 al 75 deg is only good for 90a and under 240.6 they make a 90a breaker so therefore on a commercial 100a service we need to use 1 al. I can see were someone might carry this to the 200a situation.

So if I run into a commercial 100a feeder run with 2 ser al under mass rule 4 I cant increase the magnitude of the violation by extending circuits from it.......right?

 

[texie]

Ok so im looking deeper into it and what I found is that under 310.15 (b)(7) for 100a residential service I can use 2 al. 310.15 says 2 al 75 deg is only good for 90a and under 240.6 they make a 90a breaker so therefore on a commercial 100a service we need to use 1 al. I can see were someone might carry this to the 200a situation.

So if I run into a commercial 100a feeder run with 2 ser al under mass rule 4 I cant increase the magnitude of the violation by extending circuits from it.......right?

I can't comment on the Mass. rules , but under the NEC , you are correct.