gerry
Member
- Location
- New Jersey
Can anyone explain why conduit is not the size it says it is and how this came to be? Thanks,just curious.
Electrical conduit
- Thread starter gerry
- Start date
- Status
- Location
- Bremerton, Washington
Re: Electrical conduit
Its a nominal size and is the ID. Its one of those old standards, such as wire size number gets bigger as the wire is smaller. And what is that 00 or 0000 size about anyway?
Its a nominal size and is the ID. Its one of those old standards, such as wire size number gets bigger as the wire is smaller. And what is that 00 or 0000 size about anyway?
Ed MacLaren
Senior Member
Re: Electrical conduit
When conduit was first produced, it was made the same size as water pipe, so that the same tools (threading equipment) could be used.
Ed
When conduit was first produced, it was made the same size as water pipe, so that the same tools (threading equipment) could be used.
Ed
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: Electrical conduit
I know that the sizes of the large motor operated valves made by one specific company had the same problem. Their model ?SMB 00? is bigger than their model ?SMB 0.?
I think it is like the situation of the statue on top of the Chicago Board of Trade Building. There is no face sculpted in that statue, just the general shape of a head. That is because, when it was built, nobody ever expected there to be another building high enough for anyone to be able to see the face anyway, so why spend the time and money creating a face? I learned this story while standing in the Sears Tower observation deck, looking far down towards the Chicago Board of Trade Building.
I think it comes from the early expectation that nobody would need a wire bigger than such-and-such, so you don?t have to worry about needing too many wire sizes. Then we build bigger stuff and needed bigger wires. If a #8 is bigger than a #10, and if a #6 is bigger than a #8, then what can you do when you want to build something bigger than #1? You go to ?0,? of course. But what about a bigger wire? That led to the 00, the 000, and the 0000. I suppose they could have named the 250 MCM as a 5/0, and kept up that convention. But someone said enough is enough.
I know that the sizes of the large motor operated valves made by one specific company had the same problem. Their model ?SMB 00? is bigger than their model ?SMB 0.?
I think it is like the situation of the statue on top of the Chicago Board of Trade Building. There is no face sculpted in that statue, just the general shape of a head. That is because, when it was built, nobody ever expected there to be another building high enough for anyone to be able to see the face anyway, so why spend the time and money creating a face? I learned this story while standing in the Sears Tower observation deck, looking far down towards the Chicago Board of Trade Building.
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