Residential sub-panel

[high90s]

I'm installing a 100 amp sub panel in a basement and need to find out what type and size cable to run. The panel is about 70 feet away from the main panel

1) I know I need 4-conductors, but do I use table 310.15(B)(6) or 310.16 or Article 400.

2) I can't remember what type of cable to order (SE), (SEW), (SEO) etc.

 

[charlie]

Re: Residential sub-panel

I questioned High90s credentials, removed his post, found that was mistaken, and have placed his post back.

High90s, I apologize. Welcome to the forum.

Charlie

 

[infinity]

Re: Residential sub-panel

1) I know I need 4-conductors, but do I use table 310.15(B)(6) or 310.16 or Article 400.

No, on 310.15(B)(6)
Yes, on 310.16
No, on 400

 

[benaround]

Re: Residential sub-panel

high90,

You will need type SER cable, it is four conductor.

frank

 

[infinity]

Re: Residential sub-panel

You also could use 2-3 MC or AC cable.

 

[allenwayne]

Re: Residential sub-panel

Charlie I see that you have gotten a taste for crow Only kidding brother just glad to see that this site hasen`t become stuff shirts,if you know what i mean

 

[luke warmwater]

Re: Residential sub-panel

Because of the wording in 310.15(B)(6), it can be argued that Table 310.15(B)(6) is applicable for this situation if this basement is in a dwelling unit.

"...For application of this section, the main power feeder shall be the feeder(s) between the main disconnect and the lighting and appliance branch-circut panelboard(s) ."

 

[charlie]

Re: Residential sub-panel

After having eaten quite a bit of crow, I am developing a taste for it with a little barbecue sauce on the side.

 

[infinity]

Re: Residential sub-panel

Because of the wording in 310.15(B)(6), it can be argued that Table 310.15(B)(6) is applicable for this situation if this basement is in a dwelling unit.

I would agree that the wording is somewhat ambiguous but that section does go on to say that "Main Power Feeder" shall be between the main disconnect and the lighting and appliance branch-circuit panelboards. Would a subpanel with a feeder in the main service fit that description?

 

[George Stolz]

Re: Residential sub-panel

The 2005 states '...that serve as the main power feeder to each dwelling unit..."

I don't think a subpanel in the basement could be reasonably construed as the main feeder to the house, under the 2005.

Edit to add: The smaller the area, the harder it becomes to demonstrate the overall load diversity that justifies Table 310.15 in the first place.

Better to use the 75? Column in 310.16, in this case, IMO.

[ May 10, 2005, 12:36 AM: Message edited by: georgestolz ]

 

[luke warmwater]

Re: Residential sub-panel

George,
But was the word 'each' in your above excerpt included because in the first sentence of ...(6) in the 2005, it now includes '...dwelling units of one family, two-family, and multi-family dwellings...'??


Code does not address a 'subpanel'.
It is either a 'Lighting and Appliance Branch Circut Panelboard' or a 'Power Panelboard'.

So, in a Dwelling Unit, it may be permissable to take a 'Feeder' to another 'Lighting and Appliance Branch Circut Panelboard' and size it according to table 310.15(B)(6)
Of course, to be safe, use Table 310.16
You could also make an inquiry to your AHJ.

 

[George Stolz]

Re: Residential sub-panel

What difference does the multifamily part have?

If you have a 16-plex with two panels in each, one serving 1000 sq. ft. and one serving 300 sq. ft., one with twelve circuits and one with three, it would be highly reasonable to conclude that the panel serving the larger square footage and more branch circuits would be the "main" feeder to the dwelling unit, wouldn't it?

You guys are right, it does leave it open, but it's pretty easy to be shot down, don't you think?

 

[allenwayne]

Re: Residential sub-panel

George you can feed a sub to a sub to a sub panel ,stupid yes but allowed as long as the calculated ampacities are within allowed ampacities.I did a home years ago where the homeowner wanted each room to have it`s own panel.
Set a 60 a sub in each room ,2 breakers per room 1 lighting other receptacles.Off to the bank I went.
who am I to argue what the customer wants and is willing to pay for as long as it is code compliant

 

[George Stolz]

Re: Residential sub-panel

Originally posted by allenwayne:
Set a 60 a sub in each room ,2 breakers per room 1 lighting other receptacles.Off to the bank I went.

Allen, did you use table 310.15(B)(6) to size OCPD for the 60 amp panels?