Need back up on proper use of Table 310.15 (B)(6) 2008 NEC

[WireCop]

Guys, please comment on the use of this table. 310.15 (B)(6) having trouble getting others to understand when this table can and cannot be used. Example; meter to MDP or meter main to MDP, or MDP to pool panel or any sub panel for that matter.
I say you can't use this table for anything other than the service feeder, not sub panels. Question is only about sub panels, not if its 3 phase or type of wire used. Assume single phase standard 200 amp house panel with one 100 amp sub panel.

 

[Little Bill]

Guys, please comment on the use of this table. 310.15 (B)(6) having trouble getting others to understand when this table can and cannot be used. Example; meter to MDP or meter main to MDP, or MDP to pool panel or any sub panel for that matter.
I say you can't use this table for anything other than the service feeder, not sub panels. Question is only about sub panels, not if its 3 phase or type of wire used. Assume single phase standard 200 amp house panel with one 100 amp sub panel.

My comment:
Can only be used for dwelling types listed in the table. Well, you can read the rest of the requirements in the table.

The biggest thing is it can only be used for a panel that serves the entire load of the dwelling.
It can be used for a sub panel, if the sub panel carrys the entire load.
For example: meter to disconnect with OCPD then to panel inside the house. The panel inside is technically a sub panel, but serves the entire house load.

 

[augie47]

pretty well sums it up

 

[ceb58]

My comment:
Can only be used for dwelling types listed in the table. Well, you can read the rest of the requirements in the table.

The biggest thing is it can only be used for a panel that serves the entire load of the dwelling.
It can be used for a sub panel, if the sub panel carrys the entire load.
For example: meter to disconnect with OCPD then to panel inside the house. The panel inside is technically a sub panel, but serves the entire house load.

While your last sentence is true some may confuse that with a meter combo panel with feed through lugs. You cannot use the table if you have a meter combo and feed say a AC unit or well pump. You are not supplying the entire load from one panel.
Another no - no is having a 400 amp meter and feeding 2 -200 amp panels. Again you are not supplying the entire load from one panel.

 

[infinity]

I say you can't use this table for anything other than the service feeder, not sub panels. Question is only about sub panels, not if its 3 phase or type of wire used. Assume single phase standard 200 amp house panel with one 100 amp sub panel.

In your last example 100 amp sub off of a 200 amp panel you are correct that you cannot use that table. However you could have a subpanel and still that table if the sub carried the full load of the dwelling. For example a 200 amp disconnect adjacent to a meter with a feeder to the sub panel can still use the table.

 

[Little Bill]

While your last sentence is true some may confuse that with a meter combo panel with feed through lugs. You cannot use the table if you have a meter combo and feed say a AC unit or well pump. You are not supplying the entire load from one panel.
Another no - no is having a 400 amp meter and feeding 2 -200 amp panels. Again you are not supplying the entire load from one panel.

That's why I said "disconnect". Some places require an outside disconnect, but I could have clarified a bit I suppose.

 

[ceb58]

That's why I said "disconnect". Some places require an outside disconnect, but I could have clarified a bit I suppose.

You were clear, at least I thought so, but my point was some try to use the combo and use the table to size the wire to a sub panel inside while feeding loads from the meter combo. They have selective reading. But when you look at it in the case of a meter combo, say feeding an AC unit, you have reduced the load on the feeders but you must increase the wire size. Makes sense too me :thumbsup::slaphead:

 

[WireCop]

Agree with all but ONE

Agree with all but ONE

Meter main with feed through lugs, if you go to A/c or well pump, No good you cant use this table. Because like the rest of the replies, it must be the full load of the dwelling.
Thanks ALL

 

[Little Bill]

Meter main with feed through lugs, if you go to A/c or well pump, No good you cant use this table. Because like the rest of the replies, it must be the full load of the dwelling.
Thanks ALL

I didn't read anywhere that anyone said you could use a meter main w/feed trough lugs and supply anything else from the meter main and also use the table. As a matter of fact the opposite was posted.

 

[ceb58]

I didn't read anywhere that anyone said you could use a meter main w/feed trough lugs and supply anything else from the meter main and also use the table. As a matter of fact the opposite was posted.

No good you cant use this table

Bill, put your glasses on

 

[Little Bill]

Bill, put your glasses on

Well this time I had them on!

I was responding to the subtitle of his post which said "agree with all but one" and then listed what you quoted. I was reading that as he thought someone said you could feed A/C or whatever off a combo then feed an inside panel, then use the table.

If I was wrong, it won't be the first time!:happyno:

 

[WireCop]

Correction to prior comment

Correction to prior comment

Bill you are correct, I miss read the part about AC or well pump off meter main. Everyone that gave answers confirmed my understanding as to the proper use of Table 310.15 (B)(6):thumbsup:

 

[Little Bill]

Bill you are correct, I miss read the part about AC or well pump off meter main. Everyone that gave answers confirmed my understanding as to the proper use of Table 310.15 (B)(6):thumbsup:

Wow! I've been right twice in one week.

Wait, a dead clock is right twice a day!:roll:

 

[GoldDigger]

Wait, a dead clock is right twice a day!:roll:

Only once a day if it is a 24 hour clock or has an am/pm indicator.