FMC 3/8" -- "For utilization equipment"

[NoahsArc]

Simple question on wording (2020 but I don't think it's changed much):

348.20 Size.
A. Minimum. FMC less than metric designator 16 (trade size 1∕2) shall not be used unless permitted in 348.20(A)(1) through (A)(5) for metric designator 12 (trade size 3∕8).

1. For enclosing the leads of motors as permitted in 430.245(B)
2. In lengths not in excess of 1.8 m (6 ft) for any of the following uses:
   1. For utilization equipment
   2. As part of a listed assembly
   3. For tap connections to luminaires as permitted in 410.117(C)

So utilization equipment means... what exactly here? Only on the termination side? Anywhere in the run?
When exactly can you not use 3/8" FMC? Feeding subpanels or what isn't really "utilization equipment"?

What brings this up is I need to fish through a wall from a panel into a crawl space where I can switch to EMT. Is this okay or do I need to jump to 1/2" or use MC+jbox (which is also 3/8 and this is nanners if that's the case)?

 

[LarryFine]

So utilization equipment means... what exactly here?

I think it means point to point among the parts of equipment, and not in the circuit supplying it.

Is this okay or do I need to jump to 1/2" or use MC+jbox ...?

I'd say yes, you need 1/2" FMC or a cable like MC. Manufacturers can make cables that we can't.

 

[retirede]

Here is the article 100 definition. Does that clear things up?

 

[NoahsArc]

I think it means point to point among the parts of equipment, and not in the circuit supplying it.


I'd say yes, you need 1/2" FMC or a cable like MC. Manufacturers can make cables that we can't.

Thank you, I'll take your word as definitive here.

So what is the logic behind 3/8 FMC having these restrictions, but 3/8" MC you can sling willy nilly throughout the entire job?
It's just a sort of FMC with conductors already pulled through, I don't get it.

 

[Eddie702]

In my HO the restriction on using 3/8 is somewhat meaningless and is usually ignored. I have run across roof top exhaust fans (mushroom fans) (just for an example) that have an internal factory sleeve so you can run the wire or cable up next to the ductwork indoors and the sleeve runs into the motor compartment on the roof. I have seen these sized small enough so that 1/2" greenfield, LFMC, and LNMFC will not fit and you have to use 3/8" greenfield. 3/8" LFMC, LMNFC or MC cable.

 

[infinity]

When exactly can you not use 3/8" FMC? Feeding subpanels or what isn't really "utilization equipment"?

What brings this up is I need to fish through a wall from a panel into a crawl space where I can switch to EMT. Is this okay or do I need to jump to 1/2" or use MC+jbox (which is also 3/8 and this is nanners if that's the case)?

Utilization equipment could be an appliance, a sign, an electric heater, etc. As far as fishing 3/8 GMC you're still limited to not more than 6'.

 

[NoahsArc]

Utilization equipment could be an appliance, a sign, an electric heater, etc. As far as fishing 3/8 GMC you're still limited to not more than 6'.

So if I'm fishing from a panel down 6' and switching to EMT with a box in the middle to run to a dedicated piece of utilization equipment, is that okay?

 

[infinity]

So if I'm fishing from a panel down 6' and switching to EMT with a box in the middle to run to a dedicated piece of utilization equipment, is that okay?

The way that section is written IMO the 3/8" FMC has to go to the utilization equipment or you'll need 1/2" minimum.

 

[CoolWill]

Can you just change over to EMT without the box? As in, rigid coupling with an MC connector screwed into it?

 

[kwired]

Here is the article 100 definition. Does that clear things up?

I see nothing there that restricts it from being the supply to said equipment.

But I agree with Infinity, it must connect to the utilization equipment, and can not exceed 6 feet in length.

I also see the third option for tap conductors to luminaires being somewhat redundant - those are already covered by option 1 "utilization equipment" IMO.

 

[retirede]

I see nothing there that restricts it from being the supply to said equipment.

It doesn’t. But nothing he is planning to connect to meets that definition.