Code question of the Month

Status
Not open for further replies.
Crossman,. the maximum rating is not 20 because there is a circumstance which will allow 25 amps.
How on earth can 20 be a maximum when it is not?
 
Dennis Alwon said:
Personally the max means the max given all possibilities.
Click to expand...

Personally, I dislike questions like this because it can trip up even the most astute NEC expert.

If you answer 20, I can say you are wrong, I was talking about the ultimate highest max ever allowed under any circumstance.

If you say 25, I can say you are wrong, i was talking about the maximum rating in Table 430.52
 
crossman said:
Personally, I dislike questions like this because it can trip up even the most astute NEC expert.

If you answer 20, I can say you are wrong, I was talking about the ultimate highest max ever allowed under any circumstance.

If you say 25, I can say you are wrong, i was talking about the maximum rating in Table 430.52
Click to expand...
I agree and well stated. This is why I always did poorly in verbal questions. It seems I either read to much into the question or not enough.

I probably should have made a decision and then write the alternative answer. I would have done better.:grin:
 
M. D. said:
Crossman,. the maximum rating is not 20 because there is a circumstance which will allow 25 amps.
How on earth can 20 be a maximum when it is not?
Click to expand...

The question did not ask for the maximum setting of the breaker ever allowed in any case.

The question asked for the MAXIMUM RATING which is a precise and specific term as evidenced in Table 430.52. it doesn't ask just for the maximum ever allowed. It precisely says MAXIMUM RATING. Where in the code does it discuss maximum rating precisely in those words?

Do you have your code book handy? Look at the wording of the Table and the wording of the Exception. Nowhere does Exception 2 claim to be the MAXIMUM RATING.

I do see your point and acknowledge that your view has merit. However, my view is just as valid and that makes this an arbitrary question. If the question said "What is the largest breaker you could ever use on this pump in any case?" then I am with you. Until then, it is up in the air.
 
crossman said:
What is the maximum (go ahead and apply all your definitions to the word) allowable setting for the OCP if the 20 amp breaker will hold when the motor starts?
Click to expand...

I hope this is a joke, words have meanings it is how we communicate ,

Maximum is a word and it has meaning and it supports the 25 amp answer. If they wanted to limit the answer to the table value only ,.. they should have stated so
 
crossman said:
.

"What is the largest breaker you could ever use on this pump in any case?" then I am with you. ..
Click to expand...

That is exactly what the question asked,... any other answer is not the maximum rating allowed
 
M. D. said:
I hope this is a joke, words have meanings it is how we communicate
Click to expand...
:mad:

M. D. said:
Maximum is a word and it has meaning and it supports the 25 amp answer. If they wanted to limit the answer to the table value only ,.. they should have stated so
Click to expand...

The question did not ask for the "maximum" with its Websters definition.

The question asked for the "maximum rating" with it being defined by the text in the code.

The "maximum rating" is an explicit and well-defined term given by the values in Table 430.52.

I can see your point. I would hope that you can understand mine.

Please read post #22. If I was grading a test that you took, and this question was on the test, do you see that I could grade it either way?

You answer 25, I say you are wrong and I can support my conclusion. You say 20, and I can still say you are wrong, and support that.

BAD QUESTION.
 
well i recognized this question, and its in our states electrical newsletter, the thing is, we have to wait till next month to get the answer the writer intended. lol
 
Well, at least we all agree that if this was an actual installation, we would first come up with 20 amps and we would use that, then if the breaker tripped on starting, we could go to a 25.

All this other argument is just assumptions and intent.
 
crossman said:
It did not ask for the "maximum rating allowed". It asked for the maximum rating as defined by Table 430.52.
Click to expand...

right it asked "What is the maximum rating for an inverse time circuit breaker..." I threw in the word allowed ,...silly me ,, it did not however mention any definition found in 430.52 ..I see your point ,.. the writer was lazy. I'd bet my socks that the answer sought is 20 .. the question asked is not appropriate for that answer .... the question sucks



brother said:
...What is the maximum rating for an inverse time circuit breaker used to provide
motor branch-circuit short-circuit and ground-fault protection for a residential 240 VAC, single-phase, ?
horsepower well pump motor, controller, and branch-circuit?
A) 30 amps, B) 25 amps, C) 20 amps, D) 15 amps.....
Click to expand...
 
Note the Title

Note the Title

crossman said:
...
Your use of "maybe" pretty much validates my claim that the writer's intent is a toss-up.:smile:
Click to expand...

Isn't it just like alot of the threads here, LOL ... Try some word substatution with the same sentence above ...

This is the Code (Statement)/Question of the Month !







Hint: One's, Code, Article
 
here is a question for all of you....

2" Rigid Metallic Conduit shall be supported at intervals not to exceed a maximum of _____ feet.

A. 10
B. 12
C. 16
D. 20
 
crossman said:
here is a question for all of you....

2" Rigid Metallic Conduit shall be supported at intervals not to exceed a maximum of _____ feet.

A. 10
B. 12
C. 16
D. 20
Click to expand...

I will take 'D. 20'
 
crossman said:
here is a question for all of you....

2" Rigid Metallic Conduit shall be supported at intervals not to exceed a maximum of _____ feet.

A. 10
B. 12
C. 16
D. 20
Click to expand...

Another poor question-- 10, maybe 16 or possibly 20. :smile:
 
Iwire:

But that 20 feet is a maximum under very specific conditions. Under other conditions, the maximum is 10 feet. I say this is actually a bad question.

Let's turn it around. Say an apprentice was running 2" rigid conduit and he came to you and asked what was the maximum distance he could use between supports. What would you tell him?
 
crossman said:
Iwire:

But that 20 feet is a maximum under very specific conditions. Under other conditions, the maximum is 10 feet.
Click to expand...

Sorry I know the code. :grin:

I say this is actually a bad question
Click to expand...

Your question asked for the maximum distance, that is a specific question and has a specific answer.

Let's turn it around. Say an apprentice was running 2" rigid conduit and he came to you and asked what was the maximum distance he could use between supports. What would you tell him?
Click to expand...

Well in that case I would have to know the specifics of his installation.

Your question as written did not need more information. :)
 
The ANSWER to code question

The ANSWER to code question

Last Month?s Question: What is the maximum rating for an inverse time circuit breaker used to provide
motor branch-circuit short-circuit and ground-fault protection for a residential 240 VAC, single-phase, ?
horsepower well pump motor, controller, and branch-circuit? A) 30 amps, B) 25 amps, C) 20 amps, D) 15
amps.



The answer is: C) The motor full load current is 6.9 amps (NEC Table 430.248) multiplied by the
percentage of motor full load current for an inverse time circuit breaker (250% from NEC Table 430.52)
which equals 17.25 amps. The next highest standard OCPD (NEC 430.52, Exception No. 1) is 20 amps.
 
Status
Not open for further replies.
Top