What Happended to 1999 NEC 384-16(D)

[kingpb]

In the 1999 Code 384-16(D) specifically stated that the total continuous load on any overcurrent device in a panelboard could not be loaded to more then 80% unless (Exception) specifically rated for 100%.

What happened to this statement, because in the 2002 when this section changed to 408.16 this was taken out, and it does not appear through the 2008.

So, does anybody no where it resides now, I can't seem to find the 80% breaker loading rule.

 

[raider1]

I don't see where 408.16 in the 2002 NEC said anything about the breakers in the panelboard. This section just dealt with providing overcurrent protection of the panelboards themselves. By the way 408.16 moved to 408.36 and the distinction between lighting and appliance panelboards and panelboards was removed.

Asa far the the code section that specifies breaker to be loaded to 80% of the continuous load check out 210.20 for branch circuits, 215.3 for feeders.

Chris

 

[kingpb]

Thanks for the follow-up, it appears when they took it out they slid it into the branch circuit section 210.20, which is where it probably belonged anyway.

When they did this they also started using the 125% nomenclature and dropped the 80% verbiage. At least the 125% is more consistent throughout the NEC. I think that's why I couldn't find it, (looking for 80%)

I wish manufacturer's would start making all breakers 100% rated, like IEC rated equipment is, would make everyone's life easier.

 

[dkidd]

2001 ROP

(Log #880)
9- 107 - (384-16(c)): Accept
SUBMITTER: Dan Leaf, Palmdale, CA
RECOMMENDATION: Delete this section.
SUBSTANTIATION: This section is superfluous as it is already
covered in Sections 210-19(a), 210-20(a), and 215-3 in a clearer
fashion and not limited to panelboards. It may also be somewhat
misleading since the requirement is not in Part B Switchboards,
nor Article 380 for circuit breakers and fused switches. The
requirements of the above noted sections apply without
distinction as to enclosure types and correlate with UL maximum
load restrictions which generally apply to circuit breakers, fused
switches, and switchboards. The present wording may be
confusing if a total load consists of both continuous load and
noncontinuous load. For example, a 20-amepre circuit supplying
ten general use receptacles (computed 15-ampere noncontinuous
load) and 3-amperes continuous lighting load; total load exceeds
80 percent of the overcurrent device rating and violates this
section as written. However, per Sections 210-19(a) and 210-
20(a) the overcurrent device is not less than the 15-ampere
noncontinuous load plus 125 percent of the continuous load
(3.75 amperes), or 18.75-amperes, and complies with those
sections.
PANEL ACTION: Accept.
Delete Section 384-16(d) and the Exception.
PANEL STATEMENT: The panel assumes that the submitter is
referring to Section 384-16(d).
NUMBER OF PANEL MEMBERS ELIGIBLE TO VOTE: 11
VOTE ON PANEL ACTION:
AFFIRMATIVE: 10
NEGATIVE: 1
EXPLANATION OF NEGATIVE:
REED: Section 384-16(d) correctly limits the load on any
overcurrent devices in the panelboard, including the main, which
is not covered by the referenced Articles 210 and 215. In
addition, Section 210-19 covers the conductor sizing, not the size
of the overcurrent devices. Having the present ?(d)? adds clarity
to the requirements for panelboards.
COMMENT ON AFFIRMATIVE:
DEMING: I agree with the panel action. However, if 384-16(d)
and the Exception are to be deleted then the present paragraphs
need to be renumbered as follows:
(e) should become (d)
(f) should become (e)
(g) should become (f).

 

[jim dungar]

I wish manufacturer's would start making all breakers 100% rated, like IEC rated equipment is, would make everyone's life easier.

Breakers are intended to protect conductors, therefore they have similar sizing requirements, primarily the 125% factor.

The reality is, all breakers are built as 100% rated devices. The 80% limit comes from them being mounted into enclosures. 100% rated device require lots of ventilation.