200amp service extending to existing 200amp panel

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micmike

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I am adding on an addition to my home which is on exterior wall which requires me moving the electrical service. I have installed a new 200 amp panel and at a the new location. Local supply house sold me snap in sub feed lugs that will accomodate 4/0 Al SER that I have to extend to my existing panel. This panel will be treated as a sub where grounds and neutrals will be separated. Can the new panels "service disconnect" act as the "overcurrent protection" for these new feeds or is inspector going to want to see a 200 amp breaker on there.

If this is not the solution, can the existing enclosure be converted to a splice box and the 18 circuits be brought back to new panel (approx 25').

Mike
 
micmike said:
I am adding on an addition to my home which is on exterior wall which requires me moving the electrical service. I have installed a new 200 amp panel and at a the new location. Local supply house sold me snap in sub feed lugs that will accomodate 4/0 Al SER that I have to extend to my existing panel. This panel will be treated as a sub where grounds and neutrals will be separated. Can the new panels "service disconnect" act as the "overcurrent protection" for these new feeds or is inspector going to want to see a 200 amp breaker on there.
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It sounds good except for the 4/0 AL, that is questionable.

What size will the new service conductors be supplying the new panel?
 
The main panel feed thru lugs are protected by the panels main breaker-- no need for another breaker. The purpose of that panel is to avoid further cost for another breaker.

Here is the kicker-- If you are under the 2008 then SER used as a feeder is no longer good for 180 amps. It has been reduced down to the 60C column which makes it only suitable for 150 amps.

I am not sure how an inspector will look at this--
The feeder conductors to a dwelling unit shall not be required to have an allowable ampacity rating greater than their service-entrance conductors.
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Thus if 4/0 is used as your SE conductors then you should be okay. I still think this can be a gray area.
 
Dennis Alwon said:
Here is the kicker-- If you are under the 2008 then SER used as a feeder is no longer good for 180 amps. It has been reduced down to the 60C column which makes it only suitable for 150 amps.

I am not sure how an inspector will look at this--

Thus if 4/0 is used as your SE conductors then you should be okay. I still think this can be a gray area.
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What is gray? :) Other then my hair :grin:

If he uses 4/0 AL per Table 310.15(B)(6) to size his new service conductors then the feeder from the service panel to the sub panel can also use 4/0 AL.
 
iwire said:
What is gray? :) Other then my hair :grin:

If he uses 4/0 AL per Table 310.15(B)(6) to size his new service conductors then the feeder from the service panel to the sub panel can also use 4/0 AL.
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Yeah I know but as I mentioned in an earlier thread the 4/0 used as se conductors is rated higher than the ser used as a feeder. The code section I quoted says it is not required to have a larger ampacity than the se conductors. 4/0 ser does not have as large an ampacity as the SE wires.

It seems gray to me-- perhaps I am over reading but that's how I see it.

Edit-- at least you have hair :grin:
 
Dennis Alwon said:
It seems gray to me-- perhaps I am over reading but that's how I see it.
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So you really think an inspector would force larger feeder conductors then the service conductors?


Edit; :D
 
iwire said:
So you really think an inspector would force larger feeder conductors then the service conductors?


Edit; :D
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I have seen some crazy things enforced but I certainly can see the ser ampacity is not larger than the se conductors. I think there is an issue here.
 
Dennis Alwon said:
I have seen some crazy things enforced but I certainly can see the ser ampacity is not larger than the se conductors. I think there is an issue here.
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We will have to remain in disagreement here.
 
iwire said:
So you really think an inspector would force larger feeder conductors then the service conductors?
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310.(B)(6) does state, "The feeder conductors to a dwelling unit shall not be required to have an allowable ampacity rating than their service-entrance conductors"
However, I am not sure that would apply here, since it is not originating from a disconnect, but a panelboard that may have some of the load on it.
 
JohnJ0906 said:
310.(B)(6) does state, "The feeder conductors to a dwelling unit shall not be required to have an allowable ampacity rating than their service-entrance conductors"
However, I am not sure that would apply here, since it is not originating from a disconnect, but a panelboard that may have some of the load on it.
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So basically you saying that 4/0 AL would be good from the utility to the service panel, we would then serve loads from that service panel and supply the sub panel but the feeder to the sub panel would have to be like 300 AL?

I find that unfathomable for any reason beyond voltage drop.
 
Personally, I don't see any problem with the OP's setup. :grin: I cant see any reason a feeder would have to be larger than the SE conductors. (Besides perhaps VD)

I just threw that out for discussion.
 
I agree with both john and bob, however I am not sure that the code is written with our interpretation.

Bob you seem to be saying that 300 al is a larger conductor. It is but as part of a se cable it's ampacity is reduced and is no longer a larger conductor in terms of ampacity.

I realize that this install has been going on for years and I have never seen an issue with it but I believe the words don't necessarily support it.
 
iwire said:
So you really think an inspector would force larger feeder conductors then the service conductors?


Edit; :D
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Darn right, I've had inspectors want a 4/0 to a 5/8" ground rod, just hope you have one that knows what they are doing.
 
Dennis Alwon said:
I agree with both john and bob, however I am not sure that the code is written with our interpretation.
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I couldn't find an article that would support it, besides the one I quoted. That, however, doesn't mean it isn't in there. :wink:



I realize that this install has been going on for years and I have never seen an issue with it but I believe the words don't necessarily support it.
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Agreed. I think the install is OK, just not sure where the NEC article allowing it is. :grin:
 
service conductors

service conductors

Thanks for the advice.

I used 3/0 Cu from weatherhead to meter, but then seu 4/0 Al from the meter to the new panel, appoxiamately 5' from exterior wall to inside of garage. The SER 4/0 Al will be run about 30' from new garage to old panel. The inspector is using the NEC 2005 code.

Mike
 
Dennis Alwon said:
I agree with both john and bob, however I am not sure that the code is written with our interpretation.

Bob you seem to be saying that 300 al is a larger conductor. It is but as part of a se cable it's ampacity is reduced and is no longer a larger conductor in terms of ampacity.

I realize that this install has been going on for years and I have never seen an issue with it but I believe the words don't necessarily support it.
Click to expand...

I understood your position, I just do not see it that way. :)

Check out 225.2(A)(3). :wink:
 
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