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Wet Wiring

Posted by chuckwagon (My Page) on
Mon, Sep 6, 10 at 16:36

My old disposer recently started leaking. I am in the process of replacing it. The problem I have is with the wiring. I have stripped back about 6 inches from where the wiring went into the old disposer. The paper inside the sheath is wet. I do not know how far into the wiring it is wet but can only strip so far back and still have the length I need. The disposer is on a dedicated circuit.

I'd really like to avoid rerunning the line if at all possible. What are my options?

Thanks


Follow-Up Postings:

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RE: Wet Wiring

Are you saying the wiring into the disposer was NM cable? If so that is no good. You need to use a cord or other flexible means to connect directly to the unit.

I use a short appliance cord and a single receptacle under the sink.


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RE: Wet Wiring

"Are you saying the wiring into the disposer was NM cable? If so that is no good. You need to use a cord or other flexible means to connect directly to the unit. "

Not an NEC requirement.


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RE: Wet Wiring

I hope you are not saying NM cable directly into the unit is ok.


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RE: Wet Wiring

Nothing in the NEC that prohibits wiring a waste grinder directly with NM cable. The NM may be required to be in raceway, but it (NM) is an approved wiring method for such appliances.

Waste grinders are 'permitted', not required, to be cord-and-plug connected. See Art 422.16(B)(1).


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RE: Wet Wiring

I am not talking about the disposal in this case. I am talking about it being exposed under a sink. It is in violation of the first two paragraphs of 334.15 IMO.

And I didn't say it was 'required' to be cord and plug connected. That is why I specifically stated "....or other flexible means...".

I also assume you have never wired a residential disposal before. The wiring compartment in them is painfully small. I wouldn't even want to think about wiring one with 14/2NM let alone 12/2.

I am well aware of 422.16(B)(1) thank you. I have wired many of these in residential kitchens.
Larger commercial units are always hard wired, at least in my world, but I use sealtite, not cable.


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RE: Wet Wiring

"It is in violation of the first two paragraphs of 334.15 IMO. "

That may be your interpretation, but many AHJs have no objection to hard wiring a GD with NM.

It is NOT a wet location and the device is rigidly mounted.


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RE: Wet Wiring

I find that interesting, not that many AHJs don't let a LOT of stuff slide.

The not following the contour of the structure is pretty hard to get around.
The physical damage part is pretty sketchy as well. Under my sink sees quite a bit of action.
I hope I did not imply that I thought it was a wet location. It is obviously not, as you say.

In all my years I have never seen a disp hard wired with NM.


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RE: Wet Wiring

I'm not a pro, but I've seen waste disposers hard wired with NM - in rental property I own. One, in a single family house, may have been an amateur job. (I had it upgraded to AC when I had some other work done.)

However, two of them are in a duplex I own, which was built in 1979. The original owner of this duplex also owned one of the area's big electrical contractors, for what that's worth. It struck me as a bit odd, but I've also seen water heaters and furnaces wired with unsupported, unprotected NM - AFAIK these were pro jobs too.


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RE: Wet Wiring

We see professional electricians hardwire residential waste grinders with NM all the time...and we inspectors don't much batt an eye if the NM does follow contours.

It's not really a hazard and there are more important electrical issues to really get concerned about and more important battles to fight....


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RE: Wet Wiring

Well, obviously it IS a WET location, as evidenced by the OP's situation. Not to mention all the (often hand-tightened) plastic DWV plumbing under residential sinks, subject to loosening up from GD vibration... not to mention all the detergent, drain opener, myriad other liquid chems, wet dish gloves flopping around on cabinet door racks, bottled water storage, etc... not to mention considerable quantities of water running RIGHT BACK DOWN THE SPRAYER HOSE (Yet Another reason to NOT put sprayers in rental props ;')

I've used flat HD 3-wire appliance cord in the past, looped up high, but may go liquidtite in the future, esp. in rental props... belt+suspenders or OCD?... you decide. ;')


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RE: Wet Wiring

"Well, obviously it IS a WET location, as evidenced by the OP's situation."

Wet locations are deinfined in the NEC, and under a kitchen sink is NOT a wet location.

Wet locations are tub/shower areas, outdoors exposed to weather (but if some cover is provided it may be a dmap location).

The NEC is not designed to protect the wiring in the event of other failures,like a leaking drain.

There is not enough vibration form a correctly mounted GD to bother much of anything.

IOf the drain lines are coming lose the GD is not correctly attached to the sink flange or the lines are not correctly tightened.

It takes a pretty decent force to tighten the locking collar of a GD to the flange (for many units the 'jamb wrench' provides the necessary leverage to get the collar fully tightened.

If you have enough water under a sink to cause an issue with a GD, you have probably wrecked the cabinet floor also.

What is going to damage NM under a sink?


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RE: Wet Wiring

Sorry fixizin, you are wrong. This is NOT a wet location in the eyes of the code.
Just because an area might get wet due to a problem or damage does NOT mean it is a "wet location".

Brickeyee's reply is a perfect explanation.

I am not sure what you trade is but I suggest you read up a bit on the electric code before making such assumptions or conclusions.


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RE: Wet Wiring

OK, rephrase: Regardless of arbitrary designations of the NEC, underneath a kitchen sink is prone to be a wet location in rental props, and I listed several sources of water intrusion (however minimal or intermittent) from which I've personally had to remediate damage... though admittedly the damage was to cabinetry, not wiring... but the month ain't over, lol.

e.g. a kitchen GD has an upper, or "wet" compartment, where food waste and water churn vigorously, and a lower "dry" compartment where the motor and wiring live. However, the motor shaft passes through both compartments, the water-tight seal provided by (IIRC) some combo of bronze bushings and rubber O-rings... sounds like the OP suffered a failure in this shaft seal, and water found its way into the NM-B jacket. It's a cautionary tale which makes me question the "best practices" for wiring up a GD, is all I'm saying.

What is going to damage NM under a sink?

I dunno... Drain-o Max Gel? Metal buckets filled with metal cleaning utensils, given a hefty "thrust" from a slamming cab door? Toddlers w/ silverware? Rodents?... in general, "ig-nernt" tenants... or their ig-nernt guests. Admittedly, NM-B is tougher than it looks, probably way tougher than appliance cord, but certainly less tough than MC or LTite.

There is not enough vibration form a correctly mounted GD to bother much of anything.

LOL... the world is full of UNwise peeps (and mechanically UNsavvy HOT girlz)... and thin gauge stainless sinks, stamped out in Cheena... when said peeps shove a MANGO PIT(!) down a GD mounted to said ChiCom sink, HMOG, the WHOLE COUNTERTOP "DANCES", Mr. Bill! =:O

The NEC is not designed to protect the wiring in the event of other failures,like a leaking drain.

Well, the NEC is from Man, not God. Obviously Duh Code has shortcomings, hence the tri-annual updates. ;') Of late Duh Code seems blithely unconcerned with undersink plumbing mayhem, yet overly concerned with the hypothetical tangling of appliance cords on the counter tops above.

After typing this up, I conclude that while NM-B is perhaps adequate for the GD hookup, probably the more important practice is regardless whether cord, conduit, armored, or NM-B is used, this final "whip" should route immediately UPwards, and/or have a "drip loop" formed, so that leaks internal to GD don't propagate water back to j-box... agreed?

PS: It's not clear whether OP has proper j-box under sink, but it sounds like he's screwed, i.e. needs to replace a goodly length of his NM-B, eh?


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RE: Wet Wiring

Nonsense. OP isn't skee-rooed at all.

I'll fix this up right quick, gooder'n the old one, with nothin' more'n a single-gang "old work" box, a blank metal cover plate with a knockout, some FNC, a couple clamps, a couple'a wirenuts, and a bit of THWN.

If y'all can't figure out what to do with that parts list, I give up on yas.


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RE: Wet Wiring

The paper within the NM is to help protect the insulation on the individual conductors during handling and installation. Whether another person in the world agrees with me or not, I would simply ignore the described wetting and use the cable as is. That's what I would do in such a case.
The rigorous tests of the UL include immersing the individual conductors in water for an extended period of time and then applying voltage far in excess of the rated service voltage.
I would not install and use such cable for amperages and voltages above the rating.


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RE: Wet Wiring

I'd replace NM if water had saturated the kraft paper liner. I've seen insulation literally rotted away on NM that had been soaked for years.

That said, I think a liquid-tight whip is probably overkill.


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RE: Wet Wiring

Phark, good to "see" ya... your parts list is basically how I upgrade water heaters (and other outlets/appliances) when I find a "whip" of NM-B emerging from a spackled, bushing-less hole in the sheetrock, arching 4+' over a laundry folding table (not "conforming" to wall), to reach said WH... I swear I can see discolorations in the Romex jacket, from where the wet stockings were (probably) often hung to dry... =:O

Someone will chime in that this met code (in Podunk, 1897), but I won't rent out such a prop until corrected, w/ FLEX/FNC clamped to wall as far as possible.


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