School me on flexible metal conduit

[Innovate1]

Need to hook up a water heater. 120V, 30A circuit. Have the run to a box near the heater. Just need to run the flex line. I looked at what I did on a 240V unit 15 years ago and it has whats in the picture.

Seems like there are multiple kinds. Aluminum, steel, with or without wire, clamp fitting and insert fittings, etc, etc. A little confused by all the choices and wondering if there are different names for the various variations.

The ends that thread in seem like a good way to go as it avoids having to fool with the little plastic inserts and the sharp ends that could cut the insulation. Are thread in ends like in the picture but right angle readily available?

Can solid conductors be used in this situation?

Was wondering if I could use a smaller ground wire but looked it up and it appears I need to run #10 ground.

 

[Jim greengo]

Steel flex/Greenfield is usually cheapest.
Aluminum is easier to cut/work with but a lot more expensive.
How far away is the disconect,what kind of wire is feeding it?

 

[wyliesdiesels]

Need to hook up a water heater. 120V, 30A circuit. Have the run to a box near the heater. Just need to run the flex line. I looked at what I did on a 240V unit 15 years ago and it has whats in the picture.

Seems like there are multiple kinds. Aluminum, steel, with or without wire, clamp fitting and insert fittings, etc, etc. A little confused by all the choices and wondering if there are different names for the various variations.

The ends that thread in seem like a good way to go as it avoids having to fool with the little plastic inserts and the sharp ends that could cut the insulation. Are thread in ends like in the picture but right angle readily available?

Can solid conductors be used in this situation?

Was wondering if I could use a smaller ground wire but looked it up and it appears I need to run #10 ground.

youre mixing up different types of cable and conduit.

FMC- flexible metal conduit/greenfield, has no wire in it and comes in steel and aluminum

MC- metal clad cable, looks similar but has conductors already in it, including insulated ground and the jacket cannot be used for grounding. The red plastic insulating bushings are not required for this cable type. can get in aluminum and steel though i rarely see the later in stock

AC- armored cable, also looks similar and has conductors in it but no ground wire. the jacket has a bonding strip and thus can be used as the ground wire. Red plastic insulating bushings are required by code, to be used with this cable type.

The fittings for these types vary.... there are right angle fittings available for all types.[/COLOR]

With FMC, you have to add your own conductors including a ground wire, so its more work vs MC or AC. I would just go grab a roll of 10/2 MC and a couple of fittings and be done with it. Thats what was done at my shop.... my local home depot has 10/x MC in stock usually...

Yes you can use solid conductors...

The ground wire for a 30a circuit needs to be #10

 

[Innovate1]

Steel flex/Greenfield is usually cheapest.
Aluminum is easier to cut/work with but a lot more expensive.
How far away is the disconect,what kind of wire is feeding it?

I need about 4 feet to get from the wall box to the connection on the heater. It is fed by 10-2 romex. The connection on the heater is on the side with the box above so a right angle on the heater would work well. I have some greenfield and standard fittings. Have the wire (I think). Really just need a right angle fitting and don't know what's available or what to look for so it fits the conduit.

I am guessing putting romex through greenfield is not per code.

 

[Innovate1]

youre mixing up different types of cable and conduit.

MC- metal clad cable, looks similar but has conductors already in it, including insulated ground and the jacket cannot be used for grounding. The red plastic insulating bushings are not required for this cable type. can get in aluminum and steel though i rarely see the later in stock

Thanks. Very helpful to understand what's out there.

You say the red plastic bushings aren't required with MC. So what types require the bushings? I thought they were for MC. If I recall correctly, the roll of smaller MC I have came with a pack of bushings.

 

[Taco Truck]

I am guessing putting romex through greenfield is not per code.

No, but you can pull the conductors out of romex and run it through Greenfield.

 

[Norcal]

Thanks. Very helpful to understand what's out there.

You say the red plastic bushings aren't required with MC. So what types require the bushings? I thought they were for MC. If I recall correctly, the roll of smaller MC I have came with a pack of bushings.

MC does not require bushings AKA "redheads" but they are supplied as a matter of tradition because they were supplied with AC cable which does require them, that being said, I use the redheads on MC.

 

[Jim greengo]

No, but you can pull the conductors out of romex and run it through Greenfield.

That's not legal either in most places I've been around.

 

[Crazyjake8493]

That's not legal either in most places I've been around.

Correct, if the conductors inside a cable assembly are not individually labeled then it would not be code-acceptable to remove them and run them as individual conductors.

 

[alfredeneuman]

It should be mentioned that all flexible conduits, AC and MC cables are subject to the same protection from physical damage rules as NM.

 

[sberry]

I can never remember which is which, the difference in mc and AC, good reminder.

 

[rburke65]

Yes, there are 90* fittings made for the flexible conduit.

 

[wyliesdiesels]

Thanks. Very helpful to understand what's out there.

You say the red plastic bushings aren't required with MC. So what types require the bushings? I thought they were for MC. If I recall correctly, the roll of smaller MC I have came with a pack of bushings.

As previously said, theyre required for AC- armor clad cable.

The bushings come with the MC because the manufacturers got tired of getting phone calls about missing bags of bushings...

No, but you can pull the conductors out of romex and run it through Greenfield.

nope. thats not code permitted because the individual conductors inside NM-b are not labeled...

 

[nadogail]

I have used factory made "Fixture Whips" for the electric heaters I have installed in my garage workshops.

 

[Taco Truck]

nope. thats not code permitted because the individual conductors inside NM-b are not labeled...

You're right. TIL. I just always assumed they were.

 

[Norcal]

You're right. TIL. I just always assumed they were.

When NM cable had TW conductors some brands were marked but those days are gone.