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Nate Nagel

aemeijers wrote:
David Nebenzahl wrote:
On 8/20/2009 11:05 AM spake thus:

On Thu, 20 Aug 2009 10:56:39 -0700, David Nebenzahl
wrote:

Not according to publishers of the NEC, it isn't.

"The equipment grounding conductor ... shall be one or more ... of
the following: ... Electrical metallic tubing...." [2008 NEC,
Article 250.118]

I imagine they know a little more about it than you do.

EMT in a dry location - OK. But with humidity, and particularly
humidty and vibration, the integrity of the ground suffers in a short
time. I would never depend on the EMT for a safety ground.

This seems to be analogous to backstabbed connections vs.
screw-terminal connections: allowed by the NEC, but not as good a
technique.

Think about it: with EMT, all it takes is one loose screw somewhere
in the line to sever, or at least seriously degrade, the ground
connection.

That is true if you use a green wire ground too. Workmanship is the
key to any installation. Most of the industrial jobs I inspected
specified compression connectors wrench tight. That is a pretty solid
ground path. They still pulled a green wire most of the time.

Yes. I forgot to mention that when I run conduit, I much prefer the
compression connectors to the
"make-a-dimple-in-the-tubing-with-a-screw" ones, which always seem a
bit on the cheesy side to me.

Chuckle. At work, on certain data circuits, they braze or epoxy the
joints on the conduit, done with compression fittings. Before they pull
the copper or fiber, of course. Of course, a ground path isn't what they
are after.

--
aem sends...

do they also happen to have walls covered with sheets of copper soldered
together? I've worked in some places like that...

nate

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