210.21(B)(1) - Self contradictory?

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charlie b

charlie b

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NOTE: This thread is intended for entertainment purposes only. :D (By that, I mean that I am not planning to submit a change proposal for a future code cycle. :happyno: )

While checking in the code book before responding to another thread (this one: http://forums.mikeholt.com/showthread.php?t=178171 ), I stumbled upon what I find to be an interesting self-contradiction in 210.21(B)(1). You will have to spend some time roaming through article 100 to see it. Does anyone else see it? :angel:

 
The contradiction (or so it appears to be to me) is the use of the phrase "individual branch circuit" and the word "receptacle" in the same sentence, and in the same context. I submit for your consideration that, by definition, an individual branch circuit cannot supply a receptacle. If you look at the definitions of "individual branch circuit," of "utilization equipment," and of "receptacle," you will see (or at least I see) that a receptacle does not meet the definition of utilization equipment, because it does not use electrical energy for any of the purposes listed, nor for any similar purpose. How can an "individual branch circuit" be supplying only one item of utilization equipment if the only thing it supplies, a receptacle, is not utilization equipment?

OK, so now you tell me that the receptacle is a simplex, so that only one thing can be plugged in at a time. I will respond by pointing out that the definition of "individual branch circuit" does not say that it supplies only one utilization equipment at a time. I would wonder what to call the circuit, when nothing is plugged in, and wonder further if it only becomes an "individual branch circuit" when you do plug one thing in. Perhaps the only way to create an "individual branch circuit" is to hard wire the one item of utilization equipment into the outlet at the end of the circuit.

Now I get to ask, how entertaining was this? :happyyes::happyno::lol::happysad:
 
charlie b said:
How can an "individual branch circuit" be supplying only one item of utilization equipment if the only thing it supplies, a receptacle, is not utilization equipment?
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It is clear to me from the definitions that (as you wondered) when nothing is plugged into the receptacle, there is no individual branch circuit, as there is no utilization equipment. Conversely, as soon as something is plugged into the receptacle, there is an individual branch circuit.

charlie b said:
OK, so now you tell me that the receptacle is a simplex, so that only one thing can be plugged in at a time. I will respond by pointing out that the definition of "individual branch circuit" does not say that it supplies only one utilization equipment at a time.
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The definition is silent on this issue. Nothing says a branch circuit has to always be an individual branch circuit. So you plug in one load, you have an individual branch circuit; you unplug it, the individual branch circuit goes away. You plug in a different load, you again have an individual branch circuit.

BTW, given the definitions, if you have a branch circuit supplying only one duplex receptacle, then while only one piece of utilization equipment is plugged into that duplex, you have an individual branch circuit. I see no requirement that an individual branch circuit supplying a cord-and-plug-connected load utilize a simplex receptacle. Of course, if it utilizes a duplex receptacle, then the rest of 210.21(B) applies.

charlie b said:
Now I get to ask, how entertaining was this?
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Well, as a mathematician, definitions are my bread and butter, so I find it not so much entertaining as rewarding. :)

Cheers, Wayne
 
mwm1752 said:
A receptacle is a singular opening that could only supply a single piece of equipment -- does not say duplex receptacle
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Is this 'equipment'?

stock-photo-572001-three-way-adapter.jpg
 
wwhitney said:
Nothing says a branch circuit has to always be an individual branch circuit.
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arent all BC's "individual" :lol:
one ocpd, one NM cable (one set of wires), one circuit. how many loads you attach doesnt change that fact :thumbsup:

to me, some definitions do not really describe what a BC is, they kinda describe a BC's use. look at these vs the Feeder definition, see the diff?



Branch Circuit. The circuit conductors between the final
overcurrent device protecting the circuit and the outlet(s).

Branch Circuit, Appliance. A branch circuit that supplies
energy to one or more outlets to which appliances are to be
connected and that has no permanently connected luminaires
that are not a part of an appliance.

Branch Circuit, General-Purpose. A branch circuit that
supplies two or more receptacles or outlets for lighting and
appliances.

Branch Circuit, Individual. A branch circuit that supplies
only one utilization equipment.

Branch Circuit, Multiwire. A branch circuit that consists
of two or more ungrounded conductors that have a voltage
between them, and a grounded conductor that has equal
voltage between it and each ungrounded conductor of the
circuit and that is connected to the neutral or grounded
conductor of the system.
Click to expand...

Feeder. All circuit conductors between the service equipment,
the source of a separately derived system, or other
power supply source and the final branch-circuit overcurrent
device.
Click to expand...
 
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charlie b said:
The contradiction (or so it appears to be to me)...
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Is it really a contradiction if at some point in time and under certain conditions, there is no contradiction?

For example, when one utilization equipment is plugged into a single receptacle that is the only outlet on a branch circuit. As long as that condition holds true, the circuit is by definition an individual branch circuit. Unplug the equipment, and it just reverts to a branch circuit. Plug in more than one piece of utilization equipment, and it is also then just a regular branch circuit. During these conditions, are you going to pull out the receptacle and change it to one with a rating lower than the branch circuit.

If you install a receptacle with a rating less than the branch circuit rating, it is only a violation if you plug in just one utilization equipment...???

Now for the real kicker. Equipment by its very definition is both singular and plural. So several utilization equipment can be one utilization equipment, depending on perspective and/or context.
 
charlie b said:
NOTE: This thread is intended for entertainment purposes only. :D (By that, I mean that I am not planning to submit a change proposal for a future code cycle. :happyno: )

While checking in the code book before responding to another thread (this one: http://forums.mikeholt.com/showthread.php?t=178171 ), I stumbled upon what I find to be an interesting self-contradiction in 210.21(B)(1). You will have to spend some time roaming through article 100 to see it. Does anyone else see it? :angel:
Click to expand...

Yes.
 
K8MHZ said:
My point is that a single receptacle does not have a limitation of powering a single piece of equipment, if the adapter is considered equipment. Or simply even plugged in and not defined, for that matter.
Click to expand...


once the installation has been inspected & approved an owner can manipulate any installation to non compliance ( does not make it right) -- the initial code inspected work should be compliant & not based on what if"s or predicted changes.


yes, mgookin within this thread , my responses are for entertainment purposes only
 
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