Broken BX type cable on machines

Jan 23, 2010 14 Replies

The electric cable to the motor on my surface grinder is cracked at both ends. The cable is covered with plastic to keep out fluids and is attached at both ends by a brass ferrule that is held into the fitting at each end. See Photos in drop box.



Overview of the offending cable.

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The one end that's relatively intact to show how it's assembled
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The other end with the cable unravelling but still partially attached to the ferrule.
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The plastic coated area is about 5/8" diameter and the OD of the BX type metal cable is slightly greater than 1/2" - closer to 11/16".



Is there a name for this type of cable with plastic on the outside?



How would you fix this or is this something I have to get a replacement for? I have no experience with bx type cable fittings.



RWL


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Sealtite (brand name) liquid-tight flexible metallic conduit

Another brand popular locally is "Liquatite", called generically "liquatite flex".

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Kevin Gallimore

Yes: liquid-tight flexible metallic conduit.

Replace. Can't be fixed. Looks like you have maybe 2-1/2 feet of it? I'm pretty sure I've seen that conduit, and fittings, in the electrical department at Lowe's. Being as you're unfamiliar with the conduit and its fittings, though, the best thing might be to take the whole assembly to an electrical supply house, lay it on the counter, and say "I need to replace this". They'll fix you right up. Should be less than $20.

Carried by Home Despot and better electrical supply houses.

Joe Gwinn

If you wouldn't need all that length, it could be shortened about 1" at each end. Disconnect the power from the machine, of course.

After marking the wires and disconnecting them at one end, slide the liquid-tite off and unscrew the cup-like ferrules at each end, taking care no to get cut by the ends of the armor liner/BX (that's what the ferrules do, protect the wiring from sharp edges of the BX).

After cutting around the plastic covering (cicumference), peel the plastic to the cut, then hacksaw (or Dremel cutting disk) a slit in the spine of the BX (perpendicular to the length of the liquid-tite, but at an angle across the BX spine). With a plier or suitable grabbing tool, bend the BX at the slit, and it breaks away. This should leave a fairly straight end that the ferrule can be screwed back in to.

If the nuts remain in the center, where they are in the pics, you won't need to remember to put them back on.

The ferrules appear to be crushed a bit, they may need a little expanding by tapping a suitable size of socket (or other similar part) into the end, to open them a bit, to enable them to be easily screwed back on the ends of the liquid-tite.

You could add a green earth ground wire to the motor wiring, just for good measure.

As the other replies have suggested, the metal/BX type of flex conduit is available from numerous sources. There is another type in the home stores, that looks very similar, but it's just plastic without the BX armor.

You did a really good job of using pictures to show exactly what the entire situation is.

Hi RWL

If the motor and the junction box remain in the same location during operation, the conduit in question (called Sealtight Flex) can be shortened. Here's how I would do it. (retired electrician )

1 - Disconnect all power 2 - Mark all connections in both the J box and the motor box 3 - Disconnect all connections and remove the wire from the conduit 4 - Remove the brass wire protectors from each end of the conduit( they will screw/twist out) 5 - Using a fine tooth hacksaw (and preferably a miterbox) cut each end back to solid plastic sheathing 6 - Re-insert the brass protectors. ( the folded back ends should cover the plastic at the ends of the flex conduit) 7 - Re-insert the wiring, route the wires through the box fittings and tighten down the clamp nuts 8 - Remake and verify the connections, reinstall the covers 9 - Power up and test 10 - Have a cup of (your choice) and pat yourself on the back for saving a few bucks

HTH

Bob rgentry at oz dot net

I'd replace it with some SOOW cord and cord grips that have the oil/water tight rubber gromet.

Wes

-- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller

Liquidtite or Sealtite.

Ive got a shitload of connectors for both 3/8th and 1/2" versins if you need any.

Gunner

Whenever a Liberal utters the term "Common Sense approach"....grab your wallet, your ass, and your guns because the sombitch is about to do something damned nasty to all three of them.

What's SOOW cord?

RWL

Thanks for all the replies guys. Better than politics

RWL

Yall know..that politics will always get discussed, even if you guys ask a hundred questions a day,......right?

Gunner

Whenever a Liberal utters the term "Common Sense approach"....grab your wallet, your ass, and your guns because the sombitch is about to do something damned nasty to all three of them.

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The cord grips

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We have two surface grinders, they have cord connecting the spindle motor.

If you decide to replace the liquidtite, consider a different choice in fittings. The combination of a 45° and 90° fittings look like lousy routing and extra strain on your liquitite.

Wes

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Liquatite. Any better supplier will have it and the fittings.

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Given that it just goes into a handy box and not a bell box or other water tight J-box I fail to see why liquatite is even necessary. The splices subject to moisture issues are in the j-box.

All you really need is to cut it back and redo it as long as your fittings are not broken, and they do not appear to be.

Sealtite. Metallic Liquidtight Flexible Conduit

Myself, It looks like it really doesn't need the armor in a Home Shop

- that's the backside of the machine and it's used indoors. If you aren't Idiot Proofing it in an industrial situation I'd go get a chunk of severe service cord and new cord grips, and wire it up - SOOW or the like.

There are fifty different variations, supply houses only stock a few

- you might have to order. Get a cord selection guide and you can narrow down your Wants and Do Not Wants to pick your perfect cord, some makers have their own twists (like funky sheath codes for Fluorocarbon plastics or extreme high heat silicone and fiberglas) so look at their spec sheets. The basic breakdown:

S- severe service, you want this J - Junior, reduced diameter or lighter service - NO. You want heavy. O - oil resistant, OO very oil resistant, you want at least O W - water resistant T - thermoplastic sheath, for when atmosphere or chemistry would attack natural rubber. But it melts, so welding or grinding slag exposure is out.

Then you want sealing cord grips (they grab the cord with a rubber gasket) to go into the boxes, preferably with the wire-sock strain reliefs to keep the cords from pulling out. They are sized in decimal inch ranges to the cable outer sheath diameter.

If you want to stay with Sealtite, get new connectors with the same style wire sock strain reliefs, so it won't pull out if you snag something.

And you might want to go even longer on the cable or the Sealtite, so there's a big loop hanging down off the back of the machine, looks like that motor has a long vertical track to travel.

Don't try reusing those fittings, the brass ferrules on that style crimp into the Sealtite sheath, The ones with the steel/brass sleeve and separate nylon compression sealing ring work better anyway.

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