2008 SER SEU Cable

[r_merc]

I know there is a code change reguarding derating of SER and SEU except I can't find it.
Rick

 

[Dennis Alwon]

I know there is a code change reguarding derating of SER and SEU except I can't find it.
Rick

338.10(4)(a) The words exccluding art. 334.80 were omitted.

 

[raider1]

Also take note of the change in terminology of main power feeder in regards to Table 310.15(B)(6).

Chris

 

[wbalsam1]

Also take note of the change in terminology of main power feeder in regards to Table 310.15(B)(6).

Chris

Substanitive change. :smile:

 

[raider1]

Substanitive change. :smile:

This one change has generated more discussion around my area than any other change in the 2008.

This change has a wide sweeping effect in how the homes in my area are wired.

Chris

 

[augie47]

This change has a wide sweeping effect in how the homes in my area are wired.

Chris

Primarily how ?

 

[mikeames]

Ok let me get this straight, 2/2/2/ Awg SER can be protected with a 100 OCPD when used as a feeder? I know that was the case years ago, and then there was a change and now its ok on 100? I have been putting it on 90. I guess I am ignorant. Opps.

 

[benaround]

mikeames, If it is #2 Alum. ser and used indoors you have to use the 60deg. column for

ampacity, that would be 75 amps.

 

[Cow]

mikeames, If it is #2 Alum. ser and used indoors you have to use the 60deg. column for

ampacity, that would be 75 amps.

What if I was running it from my 100 amp main breaker disconnect to my indoor panel which contains all of my dwelling load?

 

[M. D.]

What if I was running it from my 100 amp main breaker disconnect to my indoor panel which contains all of my dwelling load?

Then what you've got there my friend is a main power feeder,.. and you can use the table 310.15(B) 6

 

[Dennis Alwon]

Ok let me get this straight, 2/2/2/ Awg SER can be protected with a 100 OCPD when used as a feeder? I know that was the case years ago, and then there was a change and now its ok on 100? I have been putting it on 90. I guess I am ignorant. Opps.

It is good for 100 amps if it is the main power feeder to the dwelling-- meaning it carries the entire load of the house. Otherwise as benaround stated it must be rated 75 amps using 60C.

 

[iwire]

Substanitive change. :smile:

I disagree.

There was no change, all they did was make the existing rule clearer. The intent and meaning has been the same for years.

 

[infinity]

I disagree.

There was no change, all they did was make the existing rule clearer. The intent and meaning has been the same for years.

That has always been the way the old rule was interpreted here in NJ. The 2008 just provides a better written rule.

 

[iwire]

Here is what the panel had to say in the proposal for the wording change

Panel Statement: The panel agrees that the present wording is ambiguous. It is the panel?s intent that this allowance apply only to conductors carrying 100% of the dwelling unit?s diversified load.

 

[raider1]

Primarily how ?

It was interpreted in my area under the 2005 NEC that the main power feeder could be 2 feeders run from the main service to 2 panels in the dwelling unit. This was a common practice for 400 amp services with 2 200 amp panels, and for 200 amp services with 2 100 amp panels. The wording in the 2005 NEC was very vague and the fact the feeder(s) and panel(s) were plural made it appear multiple feeders were permitted.

There was no change, all they did was make the existing rule clearer. The intent and meaning has been the same for years.

The agree that the code making panels intent has been the same for years, but the wording of the old code section did a very poor job of making their intent clear. It was very easy to misinterpret this section into applying to multiple feeders IMHO.

Chris