Is this "continous" ?

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Is this "continous" ?

  • Yes

    Votes: 2 25.0%

  • No

    Votes: 6 75.0%
  • Total voters
    8
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Electric-Light

Electric-Light

Senior Member
Continuous when maximum load is expected to last beyond 3 hours. This is purely hypothetical. I am curious because the continuousness has been a topic of controversy many times. A firmware enforcement removes user discretion from the equation.

Would this be Kosher by code as "non-continuous load"

device: dual 1kW HPS, dual 1kW output LED digital ballast for use on 120v 20A circuit.
Input 2400VA.
Firmware enforces 20A input limit, accumulation of not greater than 60Ah during any 180 minute period and that it ramps down to a input current not exceeding 16.0A for a period not less than five minutes.

Cycle:

Start: 0-175minute @ 2.4kVA
175-179 3/4 min: 2.4KVA -> 1.9kVA @ - .1kVA/min
hold 1.9kVA for five minutes(+0%, -5% tol)
ramp up to 1.9kVA ->2.4kVA @ +.1kVA/min
remain @ 2.4kVA 175min. (or 20.0A tolerance: +0%, -5%)
repeat indefinitely.

the ramp rate would preserve the visual perception that its running at steady power by avoiding abrupt output stepping. the load profile satisfies full load not reaching 3 hours and stepped down to a level not exceeding 80%, thus breaking continuity for a period that is beyond the time frame of a transient change.
 
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So its basically a load that operates at a full 20 amps for 2 hours and 55 min., and then drops down to 16 amps for 5 min. before going back to full load for another 2 hours and 55 min.

I think it would be an AHJ call - what's the paragraph number? 110.something something.

But IMO, non-continuous loads are expected to shut off once in a while to allow cooling of the wiring and such. Dropping a smidgen below 100% of the breaker rating for a couple of minutes should not count.
 
The NEC definition of 'continuous' does leave plenty of room for manipulation. A load is said to be continuous if its maximum current is expected to continue 3 hours or more.

So, if a load has an in rush current that maxes out at 35 amps and lasts one minute then drops back to 20 amps, whatever device that load is would not be continuous, since it's maximum current is not expected to continue for 3 hours or more. The 20 amps can't be considered, by definition, a continuous load because it is not the maximum.

I don't think the definition conveys the intent very well.
 
steve66 said:
So its basically a load that operates at a full 20 amps for 2 hours and 55 min., and then drops down to 16 amps for 5 min. before going back to full load for another 2 hours and 55 min.

I think it would be an AHJ call - what's the paragraph number? 110.something something.

But IMO, non-continuous loads are expected to shut off once in a while to allow cooling of the wiring and such. Dropping a smidgen below 100% of the breaker rating for a couple of minutes should not count.
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How long would it have to be and what amount of smidgen would be necessary then?;)

1 amp for 1 sec could satisfy the wording IMO.
 
jumper said:
How long would it have to be and what amount of smidgen would be necessary then?;)

1 amp for 1 sec could satisfy the wording IMO.
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I agree, there is no reason to read more into the Article 100 definition.
 
Continuous by the NEC definition? No
Continuous by a colloquial understanding? Yes
Would I treat the circuit as if it were a continuous load if it were my choice? Yes
 
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Fulthrotl said:
col·lo·qui·al
kəˈlōkwēəl/
adjective
[COLOR=#878787 !important][/COLOR]


Click to expand...

I gotta remember "demotic". When I grow up I am gonna use it in a sentence.:D


Definition of demotic

1
: of, relating to, or written in a simplified form of the ancient Egyptian hieratic writing
 
Carultch said:
Continuous by the NEC definition? No
Continuous by a colloquial understanding? Yes
Would I treat the circuit as if it were a continuous load if it were my choice? Yes
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Ditto. Continuous or not, if you had say a warehouse lit 24/7 with these 'smart lights' (or 'cheater lights', depending on your view), designing the lighting circuits right up to the edge may be fine for the branch wiring, but the lighting panel(s) that feed them may very well have problems with overheating.

We treat fixed space heating and electric water heaters with tanks as continuous when it would be fairly uncommon to operate them full power more than 3 hours... I get the feeling if your hypothetical product were to hit the market, there might be a change in the wording of what a continuous load is, or a new section for 'nearly continuous automated lighting loads' that would treat them as continuous.

You'd be totally sool if the AHJ determined these were continuous loads and had to buy panels with 100% rated breakers vs standard.
 
JFletcher said:
Ditto. Continuous or not, if you had say a warehouse lit 24/7 with these 'smart lights' (or 'cheater lights', depending on your view), designing the lighting circuits right up to the edge may be fine for the branch wiring, but the lighting panel(s) that feed them may very well have problems with overheating.

We treat fixed space heating and electric water heaters with tanks as continuous when it would be fairly uncommon to operate them full power more than 3 hours... I get the feeling if your hypothetical product were to hit the market, there might be a change in the wording of what a continuous load is, or a new section for 'nearly continuous automated lighting loads' that would treat them as continuous.

You'd be totally sool if the AHJ determined these were continuous loads and had to buy panels with 100% rated breakers vs standard.
Click to expand...

There is no reason to think the feeder of panel would be overheated.

There is no way to provide 100% rated breakers for branch circuits. Each OCPD would need its own enclosure.
 
jumper said:
Big words confuse me. Does colloquial mean "carulth's world"?:)
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Well it looks like people looked up that word's meaning, but yeah, what I mean by that word is an ordinary understanding of continuity, without focusing on the exact NEC definition of continuous load.

Another example of colloquial, is the word acronymn. Officially, an acronymn is an group of initials (initialism) that forms a pronouncible word, either matching a word in the dictionary or a brand new word. But colloquially, we tend call all initialisms as acronymns, even if we say individual letters. SER, as in SER cable, would be an acronym if we called it "sair cable", but we don't. SER is an initialism. NEC would be an acronym if we said it as "neck", but we don't. NEC is an initialism.
 
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Carultch said:
Well it looks like people looked up that word's meaning, but yeah, what I mean by that word is an ordinary understanding of continuity, without focusing on the exact NEC definition of continuous load.

Another example of colloquial, is the word acronymn. Officially, an acronymn is an group of initials (initialism) that forms a pronouncible word, either matching a word in the dictionary or a brand new word. But colloquially, we tend call all initialisms as acronymns, even if we say individual letters. SER, as in SER cable, would be an acronym if we called it "sair cable", but we don't. SER is an initialism. NEC would be an acronym if we said it as "neck", but we don't. NEC is an initialism.
Click to expand...

So, is JPEG an acronym?

:roll:
 
JFletcher said:
Ditto. Continuous or not, if you had say a warehouse lit 24/7 with these 'smart lights' (or 'cheater lights', depending on your view), designing the lighting circuits right up to the edge may be fine for the branch wiring, but the lighting panel(s) that feed them may very well have problems with overheating.

We treat fixed space heating and electric water heaters with tanks as continuous when it would be fairly uncommon to operate them full power more than 3 hours... I get the feeling if your hypothetical product were to hit the market, there might be a change in the wording of what a continuous load is, or a new section for 'nearly continuous automated lighting loads' that would treat them as continuous.

You'd be totally sool if the AHJ determined these were continuous loads and had to buy panels with 100% rated breakers vs standard.
Click to expand...

If one is really trying to game the system and build "smart lights", the CMP might end up having to reevaluate the definition of a continuous load. Such that a load must decreases to no more than 50% of its load for at least a minute out of the 3-hour time window, to count as noncontinuous. If this really were a practical issue, I think that the testing laboratories would need to contribute to the definition with a reasonable definition of a "cool-down" to determine the time and percentage.

"Smart lights" that operate at their full load for 2:59:59 hours, and then dim unnoticed for one second, then return to full load are going to nuisance trip a standard breaker if you treat them as a non-continuous load.
 
iwire said:
There is no reason to think the feeder of panel would be overheated.

There is no way to provide 100% rated breakers for branch circuits. Each OCPD would need its own enclosure.
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The panel feeder nor the branch circuits would be overheated, tho a lighting panel full of 20A breakers running at 20A 99+% of the time might be. Fully loaded breaker on top of fully loaded breaker... I'm thinking the breakers themselves would trip as the local ambient temperature, inside the panel itself, would affect the breaker trip characteristics.

Technically, one could design a lighting controller that would kick out just one cycle's worth (1/60th of a second) of power to lights every 3 hours and by definition it wouldnt be a continuous load. I do not believe that meets the code's intent, and I wouldn't design a 20A lighting circuit to run effectively continuously at 19.99A for an indefinite amount of time. ofc the NEC isnt a design manual... I'd bet that "Continuous Loads" would be redefined as any load or combination of loads that is designed to run at an averaged 80% or more of its rated maximum amperage for 3 hours or more.

Carultch said:
If one is really trying to game the system and build "smart lights", the CMP might end up having to reevaluate the definition of a continuous load. Such that a load must decreases to no more than 50% of its load for at least a minute out of the 3-hour time window, to count as noncontinuous. If this really were a practical issue, I think that the testing laboratories would need to contribute to the definition with a reasonable definition of a "cool-down" to determine the time and percentage.

"Smart lights" that operate at their full load for 2:59:59 hours, and then dim unnoticed for one second, then return to full load are going to nuisance trip a standard breaker if you treat them as a non-continuous load.
Click to expand...

agree with all of that.
 
With all due respect, this subject reminds me of the golfer who says, "If only that ball had not hit that one little branch." and the response that, "That is why the game is called golf, not if."

As others stated, if a circuit is guaranteed to turn off for one cycle (1/60th of a second) or even less, every 2 hours and 59 minutes and 59 seconds, then the circuit is not continuous and the code would not require you to calculate it as continuous.

WHO CARES! why is someone going to create market sell and even more, buy a product for a one time installation savings of a few dollars, to circumvent code, which would likely adjust in the next code cycle to specifically exclude the item, similar to the fact that the code directly requires hot water heaters to be considered continuous?
 
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