Rigid Conduit

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rbalex

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Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
I see nothing in 334 that would prevent tape on the threads. The only fight with an inspector I see with it is if you are using it as an EGC. They may want to see some type report of the ohm value.
While it isn't specific to RMC, there are several "general" thread requirements throughout Art 250. See Section 250.12, for example. If you have the ability, do a word search on thread and/or nonconductive.

I am aware the example in 250.12 specifically mentions paint, lacquer, and enamel; however, because they are parenthetic they are only examples and nonexclusive. The fundamental rule is "[n]onconductive coatings ... on equipment to be grounded shall be removed from threads and other contact surfaces to ensure good electrical continuity or be connected by means of fittings designed so as to make such removal unnecessary." So, unless you were committed to bond across a "tefloned" thread, I'd avoid it.
 

jmellc

Senior Member
Location
Durham, NC
Occupation
Facility Maintenance Tech. Licensed Electrician
Ericksons are great but they are costly. I was taught to only use them when there were no other options.
 

renosteinke

Senior Member
Location
NE Arkansas
Sometimes you just have to use a compression connector. For the other times ....

It's simply amazing just how many more turns you can put on a 'tight' connection. After all, plumbers don't have the luxury of the threads lining up either!

When you want to make the threads just a bit tighter ... here are a few tips:
First, pass the thread die over the threads again. This will often remove a few rough spots and allow you to turn things just a bit more.
Various 'anti-seize' compounds will help- and, unlike tape, will not interfere with your ground path. The various electrical termination compounds (Noalox, Coper-Kote, etc.) are actually listed for this use. (I'm, personally involved in getting C5-A so listed.)

Personally, I assemble things 'snug.' That is, just tight enough that you can feel the parts stop moving. This gives me plenty of room to tighten things up further if I need to make some bends line up. It's not as if we're worried about a 'leak' leaving puddles of electricity on the floor.
 

Rockyd

Senior Member
Location
Nevada
Occupation
Retired after 40 years as an electrician.
Ericksons are great but they are costly. I was taught to only use them when there were no other options.

A three piece Erickson isn't that bad in cost. Materials are not the big part of billing nearly as much as labor. Throwing an Erickson on is like putting a coupling in...except a lot quicker than all the effort to spin a 32" long 4" GRC short 90. Some electricians get all spun up about using a three piece, depends on what your guidleines are. I vote for effective and efficient.

If you want expensive unions - take a look at a class 1 division 1 UNY or UNF...especially if they are Robroy - that's getting expensive! :)
 

RETRAINDAILY

Senior Member
Location
PHX, arizona
A three piece Erickson isn't that bad in cost. Materials are not the big part of billing nearly as much as labor. Throwing an Erickson on is like putting a coupling in...except a lot quicker than all the effort to spin a 32" long 4" GRC short 90. Some electricians get all spun up about using a three piece, depends on what your guidleines are. I vote for effective and efficient.

If you want expensive unions - take a look at a class 1 division 1 UNY or UNF...especially if they are Robroy - that's getting expensive! :)

Erickson

$180 :-?
I got 2 guy that can spin a 90.
even if it takes a hour.


I spin 90's all day By hand they, come with built in Crank.
When it snugs up STOP.
There is no reason to make it more difficult then it already is.
 
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