Strange wire size

[karn]

I seen this Q/A and was somewhat confused by it as I've used plenty of 3/0, and 4/0, not to mention 750mcm, and my cutters go up to 2k mcm, and I've heard if 5k mcm,,, etc,, just curious as to understanding the q/a

Q: What gauge number indicates the largest diameter copper wire?

A: 00

 

[MAC702]

Where did you see it?

Doesn't sound like a source with much recognition of much of the industry.

 

[karn]

it's a question on the RVDA-RVIA exam

 

[MAC702]

Geez. We have to Google that? Okay. Some kind of certification for RV technicians, as in Recreational Vehicles.

Pretty narrow industry but it's odd that anyone would say something without knowing the limits of their expertise. Regardless, wire sizes obviously go bigger, and I've seen 7/0 on charts, even though not in our industry, as it gets the other nomenclature for above 4/0.

Was their any additional context to the question?

Was it a multiple choice, and that was the largest of the available answers, and maybe that was the point of their question?

 

[karn]

Not sure, someone taking the exam was showing me the question and was wanting to know why 2/0 was the correct answer, I didn't know if there was something strange I haven't heard of before

 

[pjones]

They probably intended to say “of the answers available what is the largest wire?”


Sent from my iPhone using Tapatalk

 

[karn]

It just appears to be poorly written overall

 

[MAC702]

If multiple choice, it makes perfect sense to test if someone knows how gauge sizes work.

 

[LarryFine]

If multiple choice, it makes perfect sense to test if someone knows how gauge sizes work.

"Lucy, you got some 'splainin' to do!"

 

[drcampbell]

"Lucy, you got some 'splainin' to do!"

Sheet metal came first, and the gauge number represented the number of times it had been through the rolling mill. That's why bigger number represent thinner metal.

When iron wire came along, they adopted the same gauge-number system that was in use for sheet iron.

When copper wire came along, they started using the same gauge-number system as for iron wire.
(there's another gauge-number system for sheet copper, that's different than the one for sheet iron & steel, but it wasn't adopted for copper wire)

When a bigger measure than #1 became needed, #0 was invented. And #00, #000, and so forth.

 

[charlie b]

When a bigger measure than #1 became needed, #0 was invented. And #00, #000, and so forth.

And just to belabor what may now be obvious, writing "00" has the same meaning as writing "2/0."

 

[Dennis Alwon]

2/0 is good for 200 amp service in a dwelling if it is copper. I think there must be more to the question

 

[K8MHZ]

Sheet metal came first, and the gauge number represented the number of times it had been through the rolling mill. That's why bigger number represent thinner metal.

When iron wire came along, they adopted the same gauge-number system that was in use for sheet iron.

When copper wire came along, they started using the same gauge-number system as for iron wire.
(there's another gauge-number system for sheet copper, that's different than the one for sheet iron & steel, but it wasn't adopted for copper wire)

When a bigger measure than #1 became needed, #0 was invented. And #00, #000, and so forth.

Wiki gives us a totally different story:

"Wire gauges may be broadly divided into two groups, the empirical and the geometric. The first includes all the older gauge measurements, notably the Birmingham gauge (B.W.G. or Stubs) and the Lancashire. The origin of the B.W.G. is obscure. The numbers of wire were in common use earlier than 1735. It is believed that they originally were based on the series of drawn wires, No. 1 being the original rod, and succeeding numbers corresponding with each draw, so that No. 10, for example, would have passed ten times through the draw plate. But the Birmingham and the Lancashire gauge, the latter being based on an averaging of the dimensions collated from a large number of the former in the possession of Peter Stubs of Warrington, have long held the leading position, and are still retained and used probably to a greater extent than the more recent geometrical gauges.


The first attempt to adopt a geometrical system was made by Messrs Brown & Sharpe in 1855. They established a regular progression of thirty-nine steps between the English sizes, No. 0000 (460 mils or about 12 mm) and No. 36 (5 mils or about 0.13 mm). Each diameter was multiplied by 0.890526 to give the next lower size. This is now the American wire gauge (AWG), and is used to a considerable extent in the United States."

https://en.wikipedia.org/wiki/Wire_gauge

 

[LarryFine]

When a bigger measure than #1 became needed, #0 was invented. And #00, #000, and so forth.

That still doesn't explain why they would say 0-0 is the largest.

 

[jeff48356]

Geez. We have to Google that? Okay. Some kind of certification for RV technicians, as in Recreational Vehicles.

Pretty narrow industry but it's odd that anyone would say something without knowing the limits of their expertise. Regardless, wire sizes obviously go bigger, and I've seen 7/0 on charts, even though not in our industry, as it gets the other nomenclature for above 4/0.

Well, 7/0 would be 350 kcmil, even though it's not what it's called in the trade.

 

[jaggedben]

Well, 7/0 would be 350 kcmil, even though it's not what it's called in the trade.

7/0 would not be 350kcmil. It would be bigger, I'm pretty sure. Wire gauge is proportional, kcmil is a consistent unit. I couldn't tell you the history of why the industry switches from one measurement system to the other above 4/0, but I know that much.

 

[wwhitney]

1/0 = 106 kcmil
4/0 = 212 kcmil (double, to within rounding)
So 7/0 = 424 kcmil

Cheers, Wayne

 

[Besoeker3]

Time to go SI, folks..........

For example, 120mm^2 is actually the real world physical dimension.

 

[kwired]

The question simply may have been

Which is the largest conductor:

A: 00

B: 18

C: 6

D: 12

Those that don't know squat may have picked 18.

 

[Jraef]

The question simply may have been

Which is the largest conductor:

A: 00

B: 18

C: 6

D: 12

Those that don't know squat may have picked 18.

Well of course, because 18 is the largest number in that list (00 only counts on roulette tables)...