Bushing Required for a single Cat 6 Cable sleeved through FMC?

[druh24]

Is a bushing required to be installed on a sleeve of FMC with one Cat 6 cable running through it?

 

[Dennis Alwon]

I doubt it but I am not certain. When in doubt add it.

 

[Dennis Alwon]

I have not seen anything in art 800 nor 348 that would require a bushing

 

[jumper]

I am gonna go with Dennis and say not required.

 

[hbiss]

Nope, but I go the extra mile and put a connector on the end with a threaded bushing. Wouldn't want any sharp edges to cut the cable.

-Hal

 

[JFletcher]

Nope, but I go the extra mile and put a connector on the end with a threaded bushing. Wouldn't want any sharp edges to cut the cable.

-Hal

This. The ends of the conduit are required to be trimmed to remove sharp edges (348.28). If you mean a cable bushing like you'd see in MC cable, no. A conduit bushing like this:

http://www.cableorganizer.com/arlin...sku=AI-EMT50&gclid=CNvnlevIoMkCFQqFfgodHOQFDw

is prudent for ENT stubs. If both ends of your sleeve are open (not terminated to a jbox, other raceway, or equipment), I'd put those on if they'd fit to avoid slicing your cable.

Out of curiosity, where are you using FMC conduit? The only time I used it for com cable was the whip from a box to an elevator cabinet for the car telephone.

and welcome to the forum!

 

[infinity]

Is a bushing required to be installed on a sleeve of FMC with one Cat 6 cable running through it?

I've seen connectors on the end, I've seen connectors with bushings and I've seen just the cut end of the FMC. Unless it were in the spec and someone were paying for it I would not install anything on the end. Once the cable is installed unless the FMC is vibrating or moving I see little chance of the edge damaging the cable.

 

[hbiss]

Once the cable is installed unless the FMC is vibrating or moving I see little chance of the edge damaging the cable.

The cable can get damaged while you are pulling it in.

Out of curiosity, where are you using FMC conduit? The only time I used it for com cable was the whip from a box to an elevator cabinet for the car telephone.

I've seen jobs where FMC was roughed down the wall to the jack location for the LV contractor to come back later and pull the cables. I've done it myself in instances where it wasn't a straight drop down the bay. Normally it would be with steel studs and AC or MC. Sometimes it's spec'd too to allow easy replacement or the addition of cables.

-Hal

 

[kwired]

This. The ends of the conduit are required to be trimmed to remove sharp edges (348.28). If you mean a cable bushing like you'd see in MC cable, no. A conduit bushing like this:

http://www.cableorganizer.com/arlin...sku=AI-EMT50&gclid=CNvnlevIoMkCFQqFfgodHOQFDw

is prudent for ENT stubs. If both ends of your sleeve are open (not terminated to a jbox, other raceway, or equipment), I'd put those on if they'd fit to avoid slicing your cable.

Out of curiosity, where are you using FMC conduit? The only time I used it for com cable was the whip from a box to an elevator cabinet for the car telephone.

and welcome to the forum!

Do they have such a bushing like you linked to that would fit FMC? If not then one is likely stuck with a connector with a bushing threaded onto it, or maybe just the connector if it has smooth enough edges or insulated throat.

 

[JFletcher]

Do they have such a bushing like you linked to that would fit FMC? If not then one is likely stuck with a connector with a bushing threaded onto it, or maybe just the connector if it has smooth enough edges or insulated throat.

I've spent a few minutes looking onine but didnt see one. Happened to have a small roll of FMC and some ENT bushings near the back steps; I checked, they dont fit, and even if they did, the cut end of my roll has sharp metal pushed inward, which would still slice the mess out of the cable when pulling (if not recut/trimmed). You'd need a bushing that fits/snaps outside as well as inside or be able to practically drop the cable down the FMC (almost zero pulling force) to not slice it even with a perfectly clean end sans bushing/fitting.

Hal, I've seen it done with ENT, which breaks cleanly enough, but never with FMC. Different locales/methods I suppose.

 

[kwired]

I've spent a few minutes looking onine but didnt see one. Happened to have a small roll of FMC and some ENT bushings near the back steps; I checked, they dont fit, and even if they did, the cut end of my roll has sharp metal pushed inward, which would still slice the mess out of the cable when pulling (if not recut/trimmed). You'd need a bushing that fits/snaps outside as well as inside or be able to practically drop the cable down the FMC (almost zero pulling force) to not slice it even with a perfectly clean end sans bushing/fitting.

Hal, I've seen it done with ENT, which breaks cleanly enough, but never with FMC. Different locales/methods I suppose.

ENT or EMT?

FMC OD will be closer to ENT diameter of same trade size - though maybe not the same size. ENT will be same/very close to RMC/IMC OD.

Seem to recall FMC usually fitting very tight if trying to use RMC straps on it.

 

[JFletcher]

ENT or EMT?

FMC OD will be closer to ENT diameter of same trade size - though maybe not the same size. ENT will be same/very close to RMC/IMC OD.

Seem to recall FMC usually fitting very tight if trying to use RMC straps on it.

ENT aka Smurf Tube. and re: the EMT bushing on FMC, the FMC I have is 1/2", the EMT bushings 3/4". That might have something to do with not fitting.

eta: I see the confusion now. Bushings are for EMT (thinwall). I was mixing them up with talking about using ENT (smurf pipe) in place of FMC.

 

[kwired]

ENT aka Smurf Tube. and re: the EMT bushing on FMC, the FMC I have is 1/2", the EMT bushings 3/4". That might have something to do with not fitting.

eta: I see the confusion now. Bushings are for EMT (thinwall). I was mixing them up with talking about using ENT (smurf pipe) in place of FMC.

Though I only used the EMT bushings I think they may have some for RMC, but still may not fit FMC very well as they are not quite same dimension as RMC from my experiences with trying to strap FMC with a RMC strap.

 

[druh24]

We just have an electrical inspector that tried to hold up giving occupancy because one of our newer electricians didn't put a connector and busing on the FMC. I would have personally installed a connector and a bushing to begin with. If I can't find a code article that does or does not require it I have to send a guy back to pull the cable back down, put the connector and bushing on and then pull the cable back up the wall and re-terminate it. Not the best way to install it in the first place but I didn't see anything "illegal" about it.

 

[ADub]

We just have an electrical inspector that tried to hold up giving occupancy because one of our newer electricians didn't put a connector and busing on the FMC. I would have personally installed a connector and a bushing to begin with. If I can't find a code article that does or does not require it I have to send a guy back to pull the cable back down, put the connector and bushing on and then pull the cable back up the wall and re-terminate it. Not the best way to install it in the first place but I didn't see anything "illegal" about it.

I like to think most inspectors aren't that ignorant.


Sent from my iPhone using Tapatalk

 

[kwired]

We just have an electrical inspector that tried to hold up giving occupancy because one of our newer electricians didn't put a connector and busing on the FMC. I would have personally installed a connector and a bushing to begin with. If I can't find a code article that does or does not require it I have to send a guy back to pull the cable back down, put the connector and bushing on and then pull the cable back up the wall and re-terminate it. Not the best way to install it in the first place but I didn't see anything "illegal" about it.

For a raceway containing CAT 6 cables?

If it were a 911 call center - maybe understandable - probably not from the general electrical inspection though, but someone more advanced going beyond basic NEC requirements to ensure reliability of the systems there.

Does he really feel this is so dangerous occupancy should be denied?



On top of that he probably missed something that really does need some attention.

 

[JFletcher]

For a raceway containing CAT 6 cables?

If it were a 911 call center - maybe understandable - probably not from the general electrical inspection though, but someone more advanced going beyond basic NEC requirements to ensure reliability of the systems there.

Does he really feel this is so dangerous occupancy should be denied?

On my aformentioned whip from box to elevator control, you can bet a missed bushing there would have been pointed out (and failed), but probably by the elevator guy.

And druh24, just unterminate it, slide the bushing over the wire, tighten to FMC, reterminate it. Will take longer to get there than to do the work. If the inspector is right or wrong is irrelevant to me here as it will take longer to prove you're right than to fix this.

 

[kwired]

On my aformentioned whip from box to elevator control, you can bet a missed bushing there would have been pointed out (and failed), but probably by the elevator guy.

And druh24, just unterminate it, slide the bushing over the wire, tighten to FMC, reterminate it. Will take longer to get there than to do the work. If the inspector is right or wrong is irrelevant to me here as it will take longer to prove you're right than to fix this.

Unterminating a single cable and slipping on a bushing is one thing, if there would be 30 cables in the raceway/sleeve - probably not so simple.

 

[infinity]

I like to think most inspectors aren't that ignorant.

I agree and I would ask for the specific code section. FWIW I've pulled literally thousands of Cat5, Cat6, Coax and other cables down FMC with nothing more than the cut end on top and have not had a single failure due the edge of the raceway.

 

[hbiss]

And how often do you think you would see a problem if you didn't put an anti-short (redhead) bushing on the ends of AC and MC? How about if you didn't use bushings in the holes of steel studs when using Romex? Probably very infrequently but the NEC requires them. The NEC doesn't specify them for data because it's LV so there is no safety issue like there is for power. But just because it's LV doesn't mean the same reasoning shouldn't be used. What's good for the goose is good for the gander and even though it's not required it's just good workmanship.

-Hal