# Connecting new dishwasher and garbage disposal -- no ground wire in the conduits.



## AllanJ (Nov 24, 2007)

Blue and yellow are standard and acceptable colors for a hot wire in the U.S.

I don't see why a ground wire cannot be run through a conduit but a ground wire may be run outside the conduit when retrofitting an existing system.

Generally a flexible conduit must have a ground wire or metal strip running through it for use as a grounding conductor.

Stranded or solid wires -- does not matter.

A rigid conduit system does not need ground wires running inside. Depending on the flexible conduit type, flexible conduit portions may need to be jumpered around (or have a ground wire run through them and connected to the boxes at both ends). (added later) Specifically the sheath of BX cable is not a good and sufficient grounding conductor.


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## Do It Right (Feb 24, 2011)

Arca,
From your description it sounds like you have BX cable feeding the dish and disposal.
With metal boxes and the wire properly clamped into them, and properly clamped to your appliances (with a well tightened metal connector), you will have established a good ground.
Problems arise from untrained people not knowing how, or not bothering to install a .50 cent connector with locknut.
It's essential when working with BX cable.

If you have "flex", (which comes without wires in it) you should be able to add a green wire to it (with BX it's not possible). The easiest way would be to replace one of the other wires at the same time as well, tying a green and white wire to the existing white wire, and pulling them through with it. (Of course make sure there is no power to the third wire while you do this).


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## BigJimmy (Jun 30, 2006)

DOIT has got it.

You probably have a thinwall/EMT raceway system. When installed properly with properly listed connectors, the raceway system is effectively bonded and a separate ground wire is in fact not required. BX/MC cable (that which is sold typically with 2 or 3 wires manufactured as part of the product) has a bare bonding wire installed at the factory. I've seen yo-yo's try to connect this to device grounding studs which is incorrect. It is there to ensure that the cable armor between cut ends maintains a low resistance. Before terminating in the box connector, many installers insert the anti-short bushing in the cable and then bend the bonding wire over it to prevent it from popping out.

FMC (flexible metallic conduit), commonly known as Greenfield, is sold empty and is intended to have conductors pulled through it following its installation. Code requires installation of an EGC for lengths over some minimal length. I cannot remember the specification as I always install one regardless.

If you take a piece of FMC and twist it against the direction in which the coil was made, you'll notice that it will begin to expand and the individual, adjacent ribs will start to loosen and "cage." If you keep going, you'll eventually wind up with something that looks like a cork screw. At this point, the conduit can start to electrically look like a coil of wire, i.e. an inductor or choke. In electronics, the choke is used to resist changes in current. Acting as an EGC, this is bad since under a fault/short condition, it will present resistance to current. To prevent this, an explicit EGC is pulled through to ensure a low-resistance ground path through the conduit.

Jimmy


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## Jim Port (Sep 21, 2007)

The use of non-typical conductor colors from a cable assembly makes me think that the OP is dealing with a conduit type setup.


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## arca (Mar 27, 2011)

Thanks guys, I really appreciate your advices. That "pull-new-wires-with-the-existing-one" technique is clever, but I'm afraid to do it -- what if the whole thing gets stuck half-way through? With my luck, it will probably happen.

I do have an FMC and Home Depot website says their aluminum FMC can be used "As a grounding conductor for lengths up to 6 feet". I don't know if mine is aluminum, it's certainly metal, so I don't think it matters much. But it's definitely less than 6 feet. 

I think I'm gonna try to fish a ground wire anyway. And can I please ask you again: Can I pull that wire only from the dishwasher to the box that houses switches for it and garbage disposal (it's above the counter)? Will it make sense? Because I don't think I can run ground wire from that box to the panel -- it's too complex for me.

Again, thank you very much, your help means a lot to me!


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## BigJimmy (Jun 30, 2006)

ARCA-

So, is the piece of FMC greater than 6ft? If not, why bother? If it is required, you only have to run the ground conductor (EGC) through the length of FMC and bond it in the box and at the appliance. Here's a tip for pulling (pushing really) the wire: Take a pair of duckbill or needlenose pliers and bend the end of the wire back on itself. This will help it pass through the FMC connector especially if it is one of the screw-in kind with a throat. You can also straighten the flex with your free hand as you push the extra wire to help your effort. I wouldn't worry about it getting stuck. If it jams, it should pull back.


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## arca (Mar 27, 2011)

Thanks, Jimmy. 

I just bought some 16 gage stranded wire (green, of course!) and will try to pull it through the conduit. If I wont succeed -- I'll have to get by conduits as ground. Is it better to connect the ground wire to the box itself (will have to drill a hole) or to the ground screws on the sides of switches?

Thanks.


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## BigJimmy (Jun 30, 2006)

arca said:


> Thanks, Jimmy.
> 
> I just bought some 16 gage stranded wire (green, of course!)


Um, you need 14 or 12 gauge wire to match the gauge of the circuit conductors!

Most metal boxes have holes in which a grounding screw can be installed. There are also clips that can be used to connect the EGC to the sides of metal box.


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## arca (Mar 27, 2011)

BigJimmy said:


> Um, you need 14 or 12 gauge wire to match the gauge of the circuit conductors!
> 
> Most metal boxes have holes in which a grounding screw can be installed. There are also clips that can be used to connect the EGC to the sides of metal box.


My bad, it's 14 gage and I was able to pull it through!!! Longer than I thought it was -- at least 8'. 

My box is ancient, it's actually a box and some kinda front frame attached to it. There are holes on the back wall of the box, but I don't want to drill a hole to my neighbor! So I found a good spot on the side of it, I'll drill a little hole and use self-tapping screw for both ground wires -- dishwasher and disposal. Can I use one grounding hole/screw to attach two ground wires from different appliances?

Thanks.


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## BigJimmy (Jun 30, 2006)

arca said:


> Can I use one grounding hole/screw to attach two ground wires from different appliances?
> 
> Thanks.


Use a piece of left over green wire and attach one piece of your green wire to the box as a pigtail and then wire nut it to the other EGC's. Use green screws or clips (for instance T&B GS 1-SC or GEE, respectively).


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## arca (Mar 27, 2011)

BigJimmy said:


> Use a piece of left over green wire and attach one piece of your green wire to the box as a pigtail and then wire nut it to the other EGC's. Use green screws or clips (for instance T&B GS 1-SC or GEE, respectively).


Thanks man!


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## BigJimmy (Jun 30, 2006)

arca said:


> Thanks man!


Hey, no problem!:thumbsup:

It's all worth it if it works out for you!

J


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## arca (Mar 27, 2011)

BigJimmy said:


> Um, you need 14 or 12 gauge wire to match the gauge of the circuit conductors!
> 
> quote]
> 
> ...


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## BigJimmy (Jun 30, 2006)

ARCA-

When I say "conductor," I mean "wire."


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## arca (Mar 27, 2011)

So, is 14 gauge OK? I have 15amp dedicated circuit (I think separate circuit breaker for the appliance means dedicated circuit) and the applianceaid.com says 15amp=min.14 gauge house wire for a dishwasher.

My DW installation manual says nothing about ground wire requirements. Only says that I need to connect ground wire to it.


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## BigJimmy (Jun 30, 2006)

Yes, 14ga. is fine if the other conductors are the same size. Assuming that the insulation is the same between your EGC/green wire and that of the circuit conductors, your green wire should look the same as the others (diameter).

Good luck!
J


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## arca (Mar 27, 2011)

Jimmy, I finally found the amp numbers on the circuit breaker switches -- it's 15amp for the disposal and 20 amp for the rest of the kitchen. That's why the wires are of different gauges for dishwasher and disposer. I'm gonna use 12 gauge ground wires for both -- can't go wrong with that.

And while I'm at it, will replace 15amp wall switch for the dishwasher that's on the 20amp circuit. The cheap/lazy/careless bastard who installed it probably figured "it's only a switch".. Well, nothing is "only a switch" in my kitchen, mister !!

Anyway I wanna thank everybody for the help I wouldn't get in any store. Trust me, I tried. There are some good folks out there, but quite often they contradict each other, so you don't know which helpful associate to believe.

Fellas, you rule!


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