How long before EMT starts to rust?

[Buck Parrish]

I had a customer ask me this question.
It'll be exposed to sun, ice, rain and water dripping off of the roof.
How long will EMT last before it starts to rust?
It's going to run along the top of RV storage for camera wires.

 

[jaggedben]

If there isn't salt water close by (less than a quarter mile) then unpainted it should last at least a decade before any major corrosion, if not much longer. I mean, it totally depends on climate and local conditions of course. You might get some tiny spots sooner than a decade. If water gets inside, especially if it sits, then you'll get rust on the inside, but it won't necessitate replacement if caught relatively quickly, and can be mostly avoided if installed so water drains out of conduit bodies or boxes (code requirement, actually).

If there's salt water or you just want to make it last longer, paint it.

 

[Strathead]

propose using aluminum EMT

 

[retirede]

It will likely last as long as that metal building it’s going to be attached to.

 

[Buck Parrish]

Thanks