EMT and aluminum rail contact

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ylmzm

Member
Location
Los Altos, CA
I have a case where I need to run EMT along the solar aluminum rails. Instead of using separate conduit supports, I can attach EMT to aluminum rail via stainless steel hooks bolted to rails, as shown in the image below. Do you see a problem with this arrangement?

IMG_2458 (1).jpg
IMG_2459 (1).jpg
 

Carultch

Senior Member
Location
Massachusetts
I have a case where I need to run EMT along the solar aluminum rails. Instead of using separate conduit supports, I can attach EMT to aluminum rail via stainless steel hooks bolted to rails, as shown in the image below. Do you see a problem with this arrangement?


The enclosure needs to be secured, independent of relying on the conduit terminations.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Use of stainless fittings to attach EMT to Al rails is necessary to avoid electrolytic corrosion if steel EMT is used. If you use galvanized pipe then direct contact may be OK.
 

Carultch

Senior Member
Location
Massachusetts
Use of stainless fittings to attach EMT to Al rails is necessary to avoid electrolytic corrosion if steel EMT is used. If you use galvanized pipe then direct contact may be OK.

What finish does EMT have that RMC doesn't have?

It is my understanding that the standard variants of both designations are both zinc on steel in some form or another.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
It's hard to find EMT that is not galvanized these days.

In my opinion worrying about contact between large galvanized and aluminum parts is generally worrying too much. In as much as it's an issue, it can generally be solved with stainless steel washers or similar small hardware. A stainless washer between this style hanger and the aluminum is a pretty decent solution. If you're near the ocean, probably a good idea to paint the galvanized parts with some enamel to lengthen life, regardless.

My worry about the OPs picture is whether the EMT is held firmly by that hook. Not much point in having something that doesn't corrode if it doesn't hold the raceway tightly anyway.
 
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