dumb question - threaded copper supply lines?

[Kristi Silber]

I read that copper water supply tubes and fittings are not threaded. I'm obviously no plumber (or inspector for that matter), but this struck me as kinda fishy. I've looked around the forum and the 'net, and there seem to be exceptions, but is this what they are - exceptions to the "rule"?

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[Rick Cantrell]

Copper "Tubes" or pipes are not threaded, and the connectors are not threaded either.
There are threaded fittings that connect pipe to plumbing fixtures.

There is no reason (that I know) that you could not use threaded fittings to connect supply pipe, but why would you?

[Kristi Silber]

I dunno - to be able to disconnect something in a space that didn't allow for a fitting? Or where the heat of sweating is a problem? But you're right of course, why thread when sweating makes a far better, cleaner seal. Thanks for setting me right.

[Corn Walker]

Well, even if you wanted to disconnect something you'd need a ground union to avoid having to dismantle the whole system to remove one section. It's much easier to just cut the tubing and then sweat on a coupling. As for the heat from the torch, I've found welding blankets to be somewhat useful in tight spaces.