But the the breakers in this "panel" are not qualified for branch
circuit protection, so it doesn't qualify as a subpanel by any stretch
of the imagination, and if it were wired permanently to a breaker larger
than 20A would violate the NEC. Depending on its construction, it may or
may not be legal if permanently wired to a 20A circuit. The safest bet
is to use it as a good rugged power strip.
But those 20A receps must be protected by 20A overcurrent
protection and the CBs in your panel aren't qualified for
branch circuit overcurrent protection.
NEC's definition of "Branch Circuit":
"Branch Circuit. The circuit conductors between the final
overcurrent device protecting the circuit and the outlet
"240-3. Protection of Conductors
Conductors, other than flexible cords and fixture wires,
shall be protected against overcurrent in accordance with
their ampacities as specified in Section 310-15, unless
otherwise permitted or required in (a) through (g)."
See 210-24 for requirements for protection of receps.
Possibly, if the materials and construction of the panel
Well, it begs an explanation for a statement that is completely against NEC
and the purpose of Circuit Breakers. Of course the breakers in your panel
are qualified for branch circuit protection. That is in fact, exactly what
they are there for. Obviously, you mean to state something else but the
vague nature of the way you have either made statements like the above and
the included NEC text without explanation of the point you are trying to
make, causes it to be difficult for others to understand what you are
saying. I can't argue with a lot of what you're trying to say, because I
can't understand what you're trying to say. There's one thought that is
occurring to me and that is that you are using the word "panel" to refer to
the unit being sold by the OP that started this whole thread as opposed to
the breaker panel in the house. Throughout this thread we have used the
word panel to refer to the later. If my guess is true then I do understand
what you are trying to say and in fact I agree. But, that's a guess and if
my guess is wrong then there's something very wrong in what you are saying.
It would have been a lot more beneficial to explain yourself briefly instead
of a reply like this which is really quite obtuse. Clearly at least one
person here is not getting the point your are trying to get across and this
response does nothing to clear that up.
Ok... but again, simply quoting NEC without an explanation of why you are
quoting it - an explanation of your objection which uses the NEC as
validation, does nothing to further a conversation, or (if it is your
intent) the understanding of the poster in error.
Didja look at the title of the thread? The original post
where Igor referred to his multi-receptacle device as a
"panel"? Do you recall referring to Igor's multi-receptacle
device as a "panel" yourself?
It seems to me "panel" has been used pretty consistently to
refer to the multi-receptacle device that is the subject of
Your guess is correct.
I did in my first post...
"That each outlet has its own breaker, is a feature similar
to what a subpanel provides (protection for individual
circuits). A power strip,at best, protects the entire
"But the the breakers in this "panel" are not qualified for
circuit protection, so it doesn't qualify as a subpanel by
of the imagination, and if it were wired permanently to a
than 20A would violate the NEC. Depending on its
construction, it may or
may not be legal if permanently wired to a 20A circuit. The
is to use it as a good rugged power strip."
I quoted the NEC only because Igor asked for a specific
provision of the NEC that supported my assertion that using
his "panel" as he originally suggested would be a
I don't know how to help if your objection is that an
individual post may be ambiguous after earlier posts have
been snipped in follow-ups, and when taken out of the
context of the entire thread.
Nope - that's not my objection Ned. I had missed at least some of the
replies in this thread. I read all that I saw, but obviously not all of
them made it to me from my ISP. There seems to be only a couple or a few
replies that I did not receive for some reason, so viewed in the context of
what appeared to have been a complete discussion, your later comments did
not make sense. At least now they do and I understand what you are trying
to say. Thanks for hanging in there on this one.
Now, a killer question. How come the breakers on the panel do not
qualify as overcurrent protection devices under NEC. They are, after
all, designed to interrupt the line if the current exceeds the rated
amount. The whole issue of just how much current can be supplied to
the panel, is depending on the answer to this question.
It's a good question. I went through this a year ago when
building a large industrial control panel. Usually when I
do this sort of thing it's for a self contained piece of
automation I've built, so this issue does not come up
because the connections to the various devices are not
"premises wiring" and do not constitute a branch circuit.
In the case in question there were many pumps and fans
powered by the panel spread around a large room, with their
wiring mingled with the plant wiring.
Even though you can buy a suitable CB for your home panel
for a few dollars, and the miniature circuit breakers
(MCBs) referenced in the article below are reasonably
priced, the breakers approved for branch circuit protection
and suitable for use in an industrial control enclosure
start around $200/ea for a 3 phase device, and are
physically very large. We ended up protecting the
conductors leaving the cabinet with Class CC fuses, which
are approved for the use. By the time you buy the fuses and
a quality finger safe holder, they're more expensive than
Here's a link to MCBs...
and the big molded case breakers...
This article is a pretty good summary of the issue. If you
want to google up more the key words are "supplementary
protection", UL 489, and UL 1077.
| Now, a killer question. How come the breakers on the panel do not
| qualify as overcurrent protection devices under NEC. They are, after
| all, designed to interrupt the line if the current exceeds the rated
| amount. The whole issue of just how much current can be supplied to
| the panel, is depending on the answer to this question.
Reminds me of another old question: can an electric range listed for
direct connection to a 60A branch circuit have 15A utility outlets
protected by small panel-mounted pop-up circuit breakers? At one time
the answer appears to have been yes since I had such a thing.
No wonder you felt like you were guessing at what I meant.
I should have realized earlier something was amiss; my
earliest post showed up on one machine here, but not the
other. I was afraid you were going to insist that each post
stand on its own as if it were a formal research paper <g>.
Glad we were able to avoid a shouting match.
Any reason this device couldn't be wired to a 30A electric clothes
dryer pigtail and plugged into a 240V dryer receptacle, to provide
120V, 60A total to downstream devices? The receptacle would have to be
all 4 proper conductors of course: 2 hots, neutral, and ground.
The individual 12 ga conductors on the device are protected by the
onboard 20A breakers. If the breakers are not qualified for branch
circuit protection, what are they qualified for, and would that be
sufficient for a non-permanent (i.e. plugged-in) device?
On 23 Feb 2005 10:01:20 -0800, email@example.com
Well, this device is not portable and is not for plugging into
receptacles, it is for permanent wiring. If you build a steel
enclosure for it, then it could be made portable, but it was not meant
By the way, the device is sold.
Exactly. They are overcurrent protection devices.
WRONG! Size the 'upstream' wiring to match whatever size of breaker
is used to feed the outlet panel. IF smaller than 120A, then the upstream
breaker will trip *before* the individual breakers. This is perfectly
acceptable. It just means that you cannot use all the sub-circuits to
maximum capacity simultaneously. Which *is* the 'normal' state of affairs.
Furthermore, 120A only needs #2 wire.
Do you work for Microsoft Tech Support? This is eerily reminiscent of their
responses -- "technically accurate, but utterly meaningless in application".
It is entirely allowable to have sub-strings with their own breakers, where
the aggregate maximum load exceeds the rating of the feedline/breaker.
If you add up the individual breakers in a typical 'home' panel, you'll find
that they often total _more_ than 150% of the main breaker rating, just for
one example. Heck, the electric stove, electric clothes dryer, and the
air-conditioner compressor will often equal the main breaker all by themselves.
Not counting the 8-10 (or more) other circuits in the house.
Furthermore, to put 20a power on each outlet, all one needs is a 60A
220V circuit with neutral. #6 wire should be perfectly adequate for
that. I recently put a subpanel into my garage and put it on a 60A
Since no one actually needs full 20A use of all six outlets, 40 amps
220V should be more than adequate. That would be equivalent to 80A use
Yep, think of a typical subpanel. Sum of the capacities of its
individual circuits usually exceeds the capacity of the breaker that
the subpanel is on, on the theory that it is highly unlikely that all
circuits would be loaded at the same time.
There is an elaborate formula/method for calculating whether the
circuits exceed capacity. I am not familiar with its details, but
exceeding the main breaker by even more than 150% is often, if not
usually, acceptable. It depends on how many loads are truly
continuous. Shop outlets do not count with the same "weight" as does
AC or electric dryer or a range.
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