It's a table that shows the ampacity ratings for the particular wire size and insulation you are using. Example: #12 THHN CU is rated @ 30amps under the 90 degree column. (#12)is the wire size, (THHN)is the type of insulation on the wire (CU)is copper. You shouldn't be using the chart unless you're a qualified electrician simply because there are many sub rules and exceptions.
nec 690
Yes. NEC 2005 440.21
I don't know what the NEC - OR 2011 is. Is that a code book for the state of Oregon? The NEC does not allow using a gas pipe as a grounding electrode. You run the risk of heating the gas to explosive temperatures.
It is because the nec standard.
1960
The table will vary from edition to edition. In the 2005 NEC, it is table 430.250. Note that these are only typical values, and will vary from motor to motor.
The NEC has a table that shows what size cable to use with each amperage and where it can be used.
The population of NEC is 31.
NEC's population is 2,011.
nec 690
NEC's motto is 'Empowered by Innovation'.
NEC stands for not elsewhere classifiable
NEC Supertower was created in 1990.
NEC Soft's population is 5,341.
NEC Soft was created in 1975.
NEC Group's population is 2,000.
NEC stands for Not Elsewhere Classified.