Definition of a Sub-panel

[Joe Tedesco]

Sub-panels - What are Sub-panels (http://electrical.about.com/od/panelsdistribution/a/sub-panels.htm)

Up until the 1993 NEC the term "subfeeder" appeared in Article 339, and in the examples, later to be deleted in the 1996 NEC.

If I am using the 1993 NEC and I install or inspect a "subfeeder" which was included in the examples for calculations in this edition would they (the subfeeders) be run into a "sub panel" or into to a panelboard inside of a cabinet?

[Dan Harris]

Ahhh.... geez Joe :)
I thought sub-panels were only used on submarines, now your providing info that states they are used on homes :D

[Joe Tedesco]

2008 NEC Section 90.2(B) Not Covered. This Code does not cover the following:

(1) Installations in ships, watercraft other than floating buildings, railway rolling stock, aircraft, or automotive vehicles other than mobile homes and recreational vehicles

FPN: Although the scope of this Code indicates that the Code does not cover installations in ships, portions of this Code are incorporated by reference into Title 46, Code of Federal Regulations, Parts 110–113.

I looked and found this: Electronic Code of Federal Regulations: (http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=807706d1cc07f52adfc74003bf9f396e&rgn=div5&view=text&node=46:4.0.1.3.14&idno=46)

Look at Subpart 111.40—Panelboards

NFPA (http://www.nfpa.org)

[H.G. Watson, Sr.]

then subfeeder now feeder Sec 215
then subpanel now feeder panelboard.
then underground subfeeder (not SE) now underground feeder and branch-circuit cable type UF Sec 340.

Same things just newer terms in attempt to harmonize and clarify.

Its a pah-tay-tah po-tay-toe thing. Lets call the whole thing off Ginger!:eek:

[Raymond Wand]

Found this article, and thought it poignant for JF, substantiates what Jerry was imparting.

Featured Article by Joe Lstiburek, Ph.D., P.Eng., Fellow ASHRAE

Vocabulary

Building Science Insight No. 024

If we don't call things by their right names we don't really understand how things work. If we don't understand how things work how can we prevent problems from happening? Or how can we fix problems when they do occur? And how can we possibly make things work better?

We are all guilty of bad-name-itus, but the Model Building Codes take the cake. They are examples of bad wording and misunderstandings. We mostly put up with the bad wording and misunderstandings in code documents because they also are the law of the land and therefore scary. In one chapter alone of the International Residential Code the same enclosure element is called three different things-none of which are defined. Why this occurs particularly in the Model Building Codes should be no surprise if you understand how they are made, modified and adopted. The fact that the Codes work as well as they do is due more to the good will of the Code Officials than the brilliance of their terminology.

I am going to attempt to do something completely arbitrary, unilateral, annoying to others and otherwise typical for me because we have to start somewhere to clear up the mess. I am going to take a run at this language thing and try to get everyone to agree. Each one of the terms we typically use or should use needs to be not just defined but defined with a performance metric. This is not easy, but necessary. Here goes.

They are building enclosures-they are not building envelopes. You put letters in an envelope not people. Building enclosures need four principle control layers: a water control layer, an air control layer, a vapor control layer and a thermal control layer. These control layers can be combined in one material or be separate. [article continues]

To read the entire feature article and find a downloadable PDF version, click here to visit our web page.

BSI-024: Vocabulary — (http://www.buildingscience.com/documents/insights/bsi-024-vocabulary)

[Fred Warner]

I thought a "layer" was a prized, money-making hen! :D