use of flex on moving equipment

[arcblast]

Hello sparkplugs...

Question: We have a swing gate that is a conveyor and has 2 motors on it, one for the conveyor drive and one for the wheel drive to open the conveyor like a door with wheels.

We currently have the power wires for the motors inside a piece of flex, liquid-tight , beneath the conveyor at the swing point. We have already had 1 instance where the flex has broken in half and the conductors inside wear in two causing overload due to high current.

I guess i have 2 questions then:
1. Is this use of flex correct by NEC ?
2. Is there a sutible subtitute ?

Any help would be great. It is my interpretation that this use of flex is not up to code as I believe the book states "..in a location where it cannot be subject to damage..." Well I would think that acting as a hinge is subjecting it to damage....just my view.

Am I even right to question this installation or am I a worry wart ?

Thanx in advance , Mike

[ May 16, 2004, 03:00 PM: Message edited by: arcblast ]

 

[bphgravity]

Re: use of flex on moving equipment

When you say, "flex, liquid-tight", do you mean Liquidtight Flexible Nonmetallic or Liquidtight Flexible Metal Conduit?

If you are using the nonmetallic, you may be able to switch to the metallic version to get more durability out of it.

 

[arcblast]

Re: use of flex on moving equipment

it is metallic......just wonderin' what the code sys and what others have used....thanx

 

[hbiss]

Re: use of flex on moving equipment

It's fine according to code. I think how you install it will have an effect on the longevity. I would use a loop but without seeing the situation I can't say for sure.

-Hal

 

[stew]

Re: use of flex on moving equipment

400.7(A)(10) allows flexible cord for this use I believe. I would use SO hard/extrahard usage cord. Although 400.8 (1) does not allow it for the fixed wiring of a "structur" this seems to be machinery in motion and I believe it is permitted.

 

[arcblast]

Re: use of flex on moving equipment

The use of SO sounds like a great idea as the wire in SO seems more flexible and forgiving as compared to the rigid nature of the #6 we are currently using...Thanx for all the replies !!!

Mike Tucker

 

[rbalex]

Re: use of flex on moving equipment

Since it is "...specifically permitted in 400.7...," it is not restricted by 400.8.

In fact, this is even permitted in Div 1 , Hazardous Locations. See 501.4(A)(2) and 501.11.

 

[arcblast]

Re: use of flex on moving equipment

Hey , nice reference !!!!....thanks for the specific info !!!

Mike