408.16(B)

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tj234

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408.16(B)
In addition to the requirements of 408.13, a power panelboard with supply conductors that include a neutral and having more than 10 percent of its overcurrent devices protecting branch circuits rated 30 amperes or less shall be protected by an overcurrent protective device having a rating not greater than that of the panelboard.
Does this mean that if there is no neutral (or if there is less than 10 percent of OCPDs 30 amperes or less) then the panelboard does not need to be protected by an OCPD. (This question is about a regular panel, not one used as service equipment.)
I seem to be having a brain lock on this, and it doesn't seem to make sense.
 
Re: 408.16(B)

A power panel configured as stated and has neutral with feeders is treated like lighting&appliance panel. without having NEC with intent section this is only my best guess.VERY GOOD question!!you got me going..
 
Re: 408.16(B)

This could be a risky response, but I am looking for other responses anyway :)

All panelboards will have some kind of OCPD ahead of or within them (or they should have).
Dave's reference is for taps, but the feeders supplying the taps have overcurrent protection.
The difference is the allowable size of the overcurrent protection.

Pierre
 
Re: 408.16(B)

pierre
so you're saying a power panelboard without a neutral or not more than 10 percent of OCPDs 30 amperes or less can be tapped. But if there is a neutral and there's more than 10 percent of OCPDs 30 amperes or less, then it cannot be tapped (without using the lower OCPD for the tap). I guess that I can see this, but is there a practical reason behind this?
And why is the reference to a power panelboard that is "almost" a lighting and appliance branch-circuit panelboard (except that loads are not said to have a neutral).

[ March 21, 2004, 08:51 PM: Message edited by: tj234 ]
 
Re: 408.16(B)

Feeders as per 240.21(B) can be tapped without OCPDs where tapped.
What I was saying is that at some point ahead of or within the enclosure of the panelboard there will be overcurrent protection.

Pierre
 
Re: 408.16(B)

TJ243, 408.13 THRU 408.16b when read as a section pretty much discribes the end of the "feed-thru" panelboard.reading the artical with this in mind,it finally makes sense!!
 
Re: 408.16(B)

408.16(A) requires each lighting and appliance panelboard to have overcurrent protection on its supply side with a rating not larger than the panelboard (see 408.14(A) for the definition of lighting and appliance panelboard).

408.16(B) expands this requirement to include certian power panelboards that are somewhat similar in use to a lighting & appliance panelboard.

In both cases, you have to provide overcurrent protection for the feeders per other chapters of the NEC. In many cases, the same breaker protects the feeders and panels.

Some power panels can go without main overcurrent protection. One example is that you could use a 200A breaker to feed 2 100A power panels through 4/0 wire. Once again, all the feeders must be protected at their ampacity, or per the tap rules in 240.


Steve
 
Re: 408.16(B)

One simple way to look at panels.

Service entrance equipment always requires the proper OCPD.

Lighting and Appliance branch circuit panels always require a main OCPD at the point where the panels receives their supply (which may be remote from the panel).

Power panel bussing is treated like feeder conductors. A main OCPD is required unless the conductors are protected under the "tap rules"
 
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