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How to under stand NEC Table 230.51(C)


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#1 vskneifl

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Posted 30 March 2012 - 03:04 AM

I was working the Spin-Up problem 1-67 and I don't understand how to read NEC Table 230.51©, is this a miss print?

#2 knd107

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Posted 30 March 2012 - 02:00 PM

I don't have the spin-up exams but I think the table is straight forward:

600V conductors shall be installed at the max support and associated clearance.

So, if you have conductors that are supported at a max of 9'-0" intervals then you need at least 6" clearance between the conductors. Basically, if they are supported at longer intervals then the more clearance you need so they don't touch each other.

#3 Ivory

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Posted 30 March 2012 - 05:30 PM

It is an error. There is a correction in the errata. I found the errata on spinups web page under the support tab

#4 vskneifl

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Posted 31 March 2012 - 12:24 AM

I do have the errata for spinup I was just confused by the table "Maximum Distance" just makes it a little confusing but I understand now.

Thanks for your help.

#5 elminses

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Posted 07 April 2012 - 09:43 PM

question 1-67 reads " using nec 2011, open conductor spacing seperation for 600v circuits must be kept by?"

table 230.51c is based on supports of X use clearances of y. we aren't given any supports distance in the problem.

article 225.14 open conductors spacings - part c seperation from other circuits - says that open conductors shall be seperated from open conductors of other circuits by 4 in.

clarification why 4in isn't the answer? The question to me is asking the minimum and we can't assume a support system?

#6 Silkworm

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Posted 22 September 2012 - 11:27 PM

I also disagree with the answer. We cannot assume a separation distance. The most reasonable answer to the problem is 4in from 225.14© in my opinion.




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