On Mar 2, 10:29*am, Pilgrim wrote:
In article , dpb wrote:
On 3/1/2013 3:11 PM, Pilgrim wrote:
Can any one tell me what the difference between rigid conduit and iron
pipe? inner finish threads on the pipe and in the fittings and any other
significant differences.

There are three standard weights for electrical conduit -- EMT
("thinwall"), IMC (intermediate metal conduit) and GRC (galvanized rigid
conduit). *Partial table of standard dimensions per relevant ANSI spec's...

* * * * * * * * GRC

* * * *MIN. WGT.
* * * */100 FOOT *O.D. * *I.D. THICKNESS
SIZE * IN LBS. *INCHES *INCHES *INCHES
1/2" * * 79 * * 0.840 * 0.632 * 0.104
3/4" * *105 * * 1.050 * 0.836 * 0.107
1" * * *153 * * 1.315 * 1.063 * 0.126
1 1/4" *201 * * 1.660 * 1.394 * 0.133
1 1/2" *249 * * 1.900 * 1.624 * 0.138
2" * * *332 * * 2.375 * 2.083 * 0.146

* * * * * * * * EMT

1/2" * * 29 * * 0.706 * 0.622 * * * * 0.042
3/4" * * 44 * * 0.922 * 0.824 * 0.049
1" * * * 65 * * 1.163 * 1.049 * * * * 0.057
1 1/4" * 96 * * 1.510 * 1.380 * 0.065
1 1/2" *111 * * 1.740 * 1.610 * 0.065
2" * * *141 * * 2.197 * 2.067 * 0.065

Steel pipe
* * * * * * * *Sch * Sch * *Sch * *Sch
* * * * OD * * *5 * * 10 * * 40 * * 80
1/2 * 0.840 *0.065 *0.083 *0.109 *0.147
3/4 * 1.050 *0.065 *0.083 *0.113 *0.154
1 * * 1.315 *0.065 *0.190 *0.133 *0.179
1 1/4 1.660 *0.065 *0.109 *0.140 *0.140
1 1/2 1.900 *0.065 *0.109 *0.145 *0.200
2 * * 2.375 *0.065 *0.109 *0.154 *0.218

As can be seen, GRC is roughly same weight as, but still slightly
lighter (thinner wall) than Sch 40 pipe but they have same OD

--

Thanks for your informative reply. What are the thread specs? Std
NPT or
something else. The couplings I have seen for GRC seen to be non tapered..
Is GRC meant to be liquid tight to prevent moisture entering?
Thanks

A recently published NEC book will tell you about all of the trade
metallic and NMC conduit. You should be able to find one at any
hardware store.