Physical Damage vs Severe Physical Damage (EMT vs RMC)

[Elect117]

344.10(E) - RMC is suitable in locations where SEVERE damage may occur.

358.10(E) - EMT is suitable in locations where physical damage may occur.

What locations would have severe physical damage?

If I wanted to wire a light through a table saw, is that severe physical damage? Like RMC can be used on the floor where forklifts can drive over it without a ramp?

I don't understand what the distinction between the two is supposed to ensure. I wonder if someone knows how to find the discussion notes on the code change. Maybe they included an example? I just can't think of a scenario that is severe physical damage in which RMC is an application.

 

[infinity]

I'm not sure if there is an actual NEC definition of severe damage but IMO an area where the raceway could be impacted by a motor vehicle would meet the definition. Here in the Northeast if you used EMT out of a meter over a sidewalk instead of SE cable that would qualify as a location where physical damage may occur from something like a snow shovel or a snow blower.

 

[Elect117]

I'm not sure if there is an actual NEC definition of severe damage but IMO an area where the raceway could be impacted by a motor vehicle would meet the definition. Here in the Northeast if you used EMT out of a meter over a sidewalk instead of SE cable that would qualify as a location where physical damage may occur from something like a snow shovel or a snow blower.

Ya, so what is severe, you know?

If EMT can hand a snow shovel then what is so severe that EMT couldn't handle it but RMC could?

It is such a weird line to draw given neither "severe physical damage" or "physical damage" are defined by any metric.

The only instances I can think of are hazardous locations which specify their wiring method anyway. Like inside a commercial cooking process (not really physical damage) and near milling or mining equipment.

So, as a theoretical, what stops someone from using RMC with conductors inside as a speed bump in a parking lot? lol

 

[Rick 0920]

I've asked the same question recently. If the plans are drawn by an engineer, then that would be a great time for an RFI. If you're in an area where the inspectors work with you instead of against you, then you might be able to have a pre-con meeting with them. If you don't CYA on things like this, you can sure spend a lot of money later. I've done distribution centers for Dollar Tree and Walmart. They have forklifts buzzing everywhere and if you use EMT on anything under 6' AFF, IMO that's a crushing hazard.

 

[Choice_Gorilla]

Opinion here, but I think it comes down to knowing the material and what it can realistically handle. Huge gray area, there are way too many variables.