PowerPanel/LightingPanel/Tap Rules

Status
Not open for further replies.
H

hillbilly

Senior Member
I have a customer who wants to add a receptacle for a camper/motor home outside his house. The existing service has a 200A Meter Main with 200A feed thru lugs. The house is fed from (2) 100A 2 pole breakers (located in the meter main) powering 2 seperate 100A breaker panels in the house. The Main lugs in the meter main are tapped (240.21(B)(1) to a adjacent 125A 6 space Main Lug panel that has (2) 2 pole breakers powering (2) 30A A/C compressors. The 125A panel (IMHO) meets the definition of a Power Panel since there is no grounded (neutral) conductor connected (408.34). The Tap (again IMHO) is within code because the ampacity of the (#1cu) tap conductors is less than the combined load and not less than the rating (125A) of the device that they supply. All of this said... If I were to install a 20A breaker in this Tap panel to supply the camper receptacle and run a grounded (neutral) wire from this receptacle directly to the Grounded terminal of the Meter Main (through existing conduit <5') connecting all enclosures) and not land it in the Tap panel would this render the Tap illegal? I get the feeling that it would, although (splitting hairs maybe) technically the neutral would not supply the Panel but rather the receptacle (408.36(B). Am I reading this right? Sorry for the long post
steve
 
The sub-panel isn't classified as a power panelboard by virtue of the fact that it has no neutral. It's the percentage of overcurrent devices protecting lighting or appliances (408.34(B))

Either way, would not it be just as easy to install a neutral conductor to the sub-panel ? Or does it not have a neutral bar ?
 
The classification of an lighting and appliance panelboard is based on it's branch circuit(s) connection to a neutral.


Code: 
408.34 Classification of Panelboards.
Panelboards shall be classified for the purposes of this article as either lighting and appliance branch-circuit panelboards or power panelboards, based on their content. [B]A lighting and appliance branch circuit is a branch circuit that has a connection to the neutral of the panelboard[/B] and that has overcurrent protection of 30 amperes or less in one or more conductors.
(A) Lighting and Appliance Branch-Circuit Panelboard. A lighting and appliance branch-circuit panelboard is one having more than 10 percent of its overcurrent devices protecting lighting and appliance branch circuits.
(B) Power Panelboard. A power panelboard is one having 10 percent or fewer of its overcurrent devices protecting lighting and appliance branch circuits.
408.35 Number of Overcurrent
 
Lady Engineer said:
i welcome all tap explanation, because for some reason I never get them.
Click to expand...

Well, this is the place to get ALL explanations. From 90.1 to Annex G, and everything in between. The explanations may not always be right, but, by and large, they are well intentioned. :)
 
If you place the 20 amp breaker in the panel, it becomes a lighting and appliance branch circuit panel, and as such requires a main or an OCPD on the line side.
Don
 
That's what I thought too Don. Although the code does state that if the Power Panel has "supply conductors that include a neutral and...." (408.36(B)(2005NEC) that it must be protected on its supply side. In my scenario the Panel doesn't have a neutral with the supply conductors [unless the return (neutral) from the receptacle is counted as a supply conductor]. I know that I'm being about as clear as the NEC Rules themselves. Anyway, I'm going to crawl under the house and run a circuit from one of the inside breaker panels. Thanks for all of the replies.
steve
 
Status
Not open for further replies.
Top