ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals

Topic Options
Rate This Topic
#59613 - 12/08/05 09:37 PM Aluminum and Galvanized conduit
ShockMe77 Offline
Member
Registered: 06/11/05
Posts: 821
Loc: Rahway, New Jersey
I'm currently working on a job installing conduit for a cell tower on the top of a 12 story building in central New Jersey. For whatever the reason, some other contractor ordered most of the material on the job for us and I had a few questions about what we had to work with.

My main question is this, is it permissible to use threaded aluminim couplings to attach a piece of 2" aluminum conduit to a factory made 2" galvanized sweep?

Also, is this wiring method ok as far as considering this pipe run as the EGC when 2-types of metals are being used in the run?
Top
Work Gear for Electricians and the Trades
#59614 - 12/08/05 11:12 PM Re: Aluminum and Galvanized conduit
LK Offline
Member
Registered: 01/21/03
Posts: 1429
Loc: New Jersey
This is the only referance i find, others may have more information, what did the project engineer have to say about it.
"The impedance of a circuit in an aluminum raceway or aluminum-sheathed cable will differ from the impedance of the same circuit in a steel raceway or steel-sheathed cable; therefore, separate raceways and cables must have the same physical characteristics. See 300.20 regarding induced currents in metal enclosures or raceways."
Top
#59615 - 12/09/05 04:12 AM Re: Aluminum and Galvanized conduit
electure Offline


Member
Registered: 12/24/00
Posts: 4259
Loc: Fullerton, CA USA
334.14 Dissimilar Metals
Where practicable, dissimilar metals in contact anywhere in the system shall be avoided to eliminate the possibilityof galvanic action. Aluminum fittings and enclosures shall be permitted to be used with steel RMC, and steel fittings and enclosures shall be permitted to be used with aluminum RMC where not subject to severe corrosive influences.

(BTW, some Noalox on the threads of the aluminum conduit will prevent the threads from galling or seizing and make installation much easier)

[This message has been edited by electure (edited 12-09-2005).]
Top
#59616 - 12/09/05 06:55 AM Re: Aluminum and Galvanized conduit
lamplighter Offline
Member
Registered: 10/05/05
Posts: 101
Loc: Clawson,Michigan,USA
Boy, this brings back memories of trying to pull new wires into buried aluminum conduit in south Fl.
The pipe was almost always nothing but white powder.
The problem got so bad that the south Florida building code didn't allow aluminum conduit within ten miles of the beach.
Top
#59617 - 12/11/05 03:50 AM Re: Aluminum and Galvanized conduit
ShockMe77 Offline
Member
Registered: 06/11/05
Posts: 821
Loc: Rahway, New Jersey
Thank you for the code referrence number. I was concerned that the 2" pipe was going to be used as the EGC but I later found out that a seperate 1" pipe had been run just for that reason. It's a neat job to be on considering I do mostly residential work and don't get to work with AL/ RMC all too much.
Top
#59618 - 12/11/05 06:57 AM Re: Aluminum and Galvanized conduit
DougW Offline
Member
Registered: 06/08/03
Posts: 1143
Loc: North Chicago, IL
Quote:

Originally posted by ShockMe77:
It's a neat job to be on considering I do mostly residential work and don't get to work with AL/ RMC all too much.


I started using AL RMC for my non-mast risers on resi gigs once I found out the PoCo & most AHJ's accepted it. It's quicker and cheaper than galvanized.

[This message has been edited by DougW (edited 12-11-2005).]
Top

Member Spotlight
Member Since: 02/23/13
Posts: 204
New in the Gallery:
SE cable question
Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box


Who's Online
0 registered (), 51 Guests and 9 Spiders online.
Key: Admin, Global Mod, Mod
 
New in the Gallery:
SE cable question
 
Top Posters (30 Days)
Admin 47
HotLine1 43
gfretwell 19
Ruben Rocha 12
Trumpy 9
 
Newest Members
Scotto, Freecrowder, clee512, Jdscott2005, FAIZAN

ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals