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jamiedolan 11-16-2008 01:47 AM

What do I do with old wires that I can't remove?
 
There are a couple circuits that I am going to rewire, and I am not going to use the pieces of NM that used to feed them anymore. They are comming down via small holes in the floor. They don't want to move when pulled on, I suspect they are stapled in place in the wall.

Do I just cut them back as close to the floor as I can? Do I label them as being dead?

Thanks
Jamie

Termite 11-16-2008 02:00 AM

If you're 100% sure they're dead, I don't see a problem with leaving the ones you can't remove due to their inaccessibility. Some people wire nut the ends just to have a warm fuzzy feeling. It never hurts to label them "abandoned/dead" either.

jamiedolan 11-16-2008 02:07 AM

Quote:

Originally Posted by thekctermite (Post 185665)
If you're 100% sure they're dead, I don't see a problem with leaving the ones you can't remove due to their inaccessibility. Some people wire nut the ends just to have a warm fuzzy feeling. It never hurts to label them "abandoned/dead" either.

The primary place I am going to do this, is there are several feeds to my kitchen, they used that 12/2 WITHOUT ground then they ran a #14 ground wire to the boxes, but I have no idea what they bonded it to, because it never made a connection to the panel. So I am going to replace every electrical circuit in the kitchen. These wires are wires I pulled from the panel, so they are dead. I just bought 35 pieces of EMT tonight and am going to run EMT to the kitchen ceiling, and then drop down the walls with Smurf Tube.

I bet you will know the answer to this. When I run EMT, I know NEC says that it can be used as the ground path. It was suggest here that I use a ground wire anyway in my EMT. If I run a ground wire in the EMT, just as an extra backup, can it be undersized since I am really relying on the EMT for the ground? i.e. could I run a #12 ground in my emt, just as a backup, even thought I may have a #8 circuit in that conduit? or do I need to go up to a #8 if I am going to use a back up ground to the EMT?

Thanks
Jamie

InPhase277 11-16-2008 08:44 AM

Quote:

Originally Posted by jamiedolan (Post 185670)
The primary place I am going to do this, is there are several feeds to my kitchen, they used that 12/2 WITHOUT ground then they ran a #14 ground wire to the boxes, but I have no idea what they bonded it to, because it never made a connection to the panel. So I am going to replace every electrical circuit in the kitchen. These wires are wires I pulled from the panel, so they are dead. I just bought 35 pieces of EMT tonight and am going to run EMT to the kitchen ceiling, and then drop down the walls with Smurf Tube.

Don't assume that to be the case. You never know. Some jackleg could have double fed a circuit. Make sure. For sure.

Quote:

I bet you will know the answer to this. When I run EMT, I know NEC says that it can be used as the ground path. It was suggest here that I use a ground wire anyway in my EMT. If I run a ground wire in the EMT, just as an extra backup, can it be undersized since I am really relying on the EMT for the ground? i.e. could I run a #12 ground in my emt, just as a backup, even thought I may have a #8 circuit in that conduit? or do I need to go up to a #8 if I am going to use a back up ground to the EMT?

Thanks
Jamie
At up to 30 amps, the ground has to be the same size as the circuit conductors. After that, follow table 250.122.

Termite 11-16-2008 10:02 AM

I agree with InPhase in full...If you elect to put a grounding conductor in there for good measure, it has to be sized correctly even though you're not required to have it. In the event that there's a fault, the ground may be the best path to clear the fault, and shouldn't be de-rated.

Besides, if you aren't running EMT the full length of the circuit's run, you have to have a ground anyway. I wouldn't give it a second though...And would always run the ground just for good measure.

jamiedolan 11-16-2008 11:02 AM

Don't assume that to be the case. You never know. Some jackleg could have double fed a circuit. Make sure. For sure.
Thanks for the reminder. I have had a meter out and been making double sure they were dead, since I have found a few stupid wiring mistakes here. I have also been working with my sub panel off, and the only thing I have connected to the old panel is the sub panel and my basement lights and a outlet for the tools I am using.

At up to 30 amps, the ground has to be the same size as the circuit conductors. After that, follow table 250.122.

My kitchen run of EMT (multiple tubes) that will supply all of the kitchen power, oven, espresso machine, then feed upstairs to get new dedicated service to the bathrooms (3), and the bar outlets (that are currently fed with a 12-2 WITHOUT ground - seriously they ran 12-2 in this house some with ground, some without).

Since the EMT can serve as a ground, and I am running a ground wire as a backup, can I run just one ground wire, say a #8, and tap off of that for multiple circuits, as long as the EMT in all interconnected in the locations where the ground wire will be jumped?

Or do I have to run a ground wire in each run of conduit, even though it is just a back up ground, since I am using EMT as my primary ground path?

I know the code says that you need to run one in each conduit, but it doesn't really address if you just running the ground wire for extra safety and you already have the EMT as your primary path.

Thanks
Jamie

jamiedolan 11-16-2008 11:05 AM

Quote:

Originally Posted by thekctermite (Post 185764)
I agree with InPhase in full...If you elect to put a grounding conductor in there for good measure, it has to be sized correctly even though you're not required to have it. In the event that there's a fault, the ground may be the best path to clear the fault, and shouldn't be de-rated.

Besides, if you aren't running EMT the full length of the circuit's run, you have to have a ground anyway. I wouldn't give it a second though...And would always run the ground just for good measure.

So does it have to be sized correctly and run in each conduit, per the regular ground wire rules in 250.122?

Basically, if your going to run a ground wire as backup to the EMT, your saying that you still have to follow all the codes as if it were your primary ground path?

I am going to run EMT to the attic and drop smurf down the walls to the lights and outlets. I was going to run a ground screw into the box, and then run a ground wire down the smurf with the other wires.

Thanks
Jamie

jwhite 11-16-2008 11:14 AM

Quote:

Originally Posted by jamiedolan (Post 185795)
So does it have to be sized correctly and run in each conduit, per the regular ground wire rules in 250.122?

Yes...

Wildie 11-16-2008 11:47 AM

Quote:

Originally Posted by jamiedolan (Post 185792)
Don't assume that to be the case. You never know. Some jackleg could have double fed a circuit. Make sure. For sure.
Thanks for the reminder. I have had a meter out and been making double sure they were dead, since I have found a few stupid wiring mistakes here. I have also been working with my sub panel off, and the only thing I have connected to the old panel is the sub panel and my basement lights and a outlet for the tools I am using.

At up to 30 amps, the ground has to be the same size as the circuit conductors. After that, follow table 250.122.

My kitchen run of EMT (multiple tubes) that will supply all of the kitchen power, oven, espresso machine, then feed upstairs to get new dedicated service to the bathrooms (3), and the bar outlets (that are currently fed with a 12-2 WITHOUT ground - seriously they ran 12-2 in this house some with ground, some without).
Since the EMT can serve as a ground, and I am running a ground wire as a backup, can I run just one ground wire, say a #8, and tap off of that for multiple circuits, as long as the EMT in all interconnected in the locations where the ground wire will be jumped?

Or do I have to run a ground wire in each run of conduit, even though it is just a back up ground, since I am using EMT as my primary ground path?

I know the code says that you need to run one in each conduit, but it doesn't really address if you just running the ground wire for extra safety and you already have the EMT as your primary path.

Thanks
Jamie

I once had an apartment building that was built in 1911. it was wired with knob and tube.
The province (Ontario) decreed that all rental premises would now require U ground receptacles.
To install these, a ground wire could be run to a water pipe ground at any convenient location.
In this instance, I was allowed to staple 14 gauge ground wire along the top of the shoe moulding, looping from receptacle to receptacle.
In my area, grounds may be retrofitted in such a manner. It is an accepted practice.

Now that GFCI receptacles are now economically available, grounds are no longer necessary. Receptacles that are GFCI protected is all that is necessary!

99jasons 11-16-2008 12:34 PM

its allways best to run the same awg wire however if you are looking to cut costs go no smaller than a #10 awg, however I think that the difference in peace of mind and cost for the smaller wire will be negligable, and yes the emt is a grounding system if it is piped completley from the pane to the boxes, it is recommended that a seperate grounging wire be run. its allway better to be safe than sorry. run a #10 or better, ground the box with the ground wire then land it in the panel and walk away worry free

DangerMouse 11-16-2008 01:40 PM

with the price of copper, you don't want to leave it in the walls! maybe it'd be best to burn the house down, then you'd have all that wonderful copper to gather up and recycle! hehehehe

DM

rgsgww 11-16-2008 01:46 PM

Quote:

Originally Posted by thekctermite (Post 185665)
It never hurts to label them "abandoned/dead" either.


11.1.4 of the 2009 and 2006 nfpa 1 (national fire code) says:

Permanent wiring abandoned in place shall be tagged or otherwise identified at its termination and junction points as "Abandoned in Place" or removed from all accessible areas and insulated from contact with other live electrical wiring or devices.


So its actually required to insulate and tag abandoned cables.

jwhite 11-16-2008 02:06 PM

Notice the "OR removed from all ACCESSABLE" locations.

The code writers are saying that it is best to remove all unused wiring, however they also recognize that sometimes this would put an excessive cost burden on the building owner. (say they had to tear out all the walls do remove the wire)

If one simply removes all the wire that is accessable, wraps a bit of tap over the ends that are left where the wire disappears into a wall, ceiling or floor, and stuffs the extra bit into the hole, so that it can never be used again, then he/or she may defer complete removal till sometime in the future when the wire is made accessable due to a more major renovation.

InPhase277 11-16-2008 04:01 PM

Quote:

Originally Posted by jamiedolan (Post 185792)

Since the EMT can serve as a ground, and I am running a ground wire as a backup, can I run just one ground wire, say a #8, and tap off of that for multiple circuits, as long as the EMT in all interconnected in the locations where the ground wire will be jumped?



All you need is a #10 up to 60 A. If your main conduit has say, two 20 A circuits and a 40 A, then you just run one #10 ground. If you have conduits that tap from there, you don't need a ground wire in those, but if you do install one, it only needs to be sized to the largest circuit in that pipe. So, a #10 comes in, and bonds to the box. From there, another conduit leaves with only a 20 A circuit, then all you need is a #12 ground.

Quote:

Or do I have to run a ground wire in each run of conduit, even though it is just a back up ground, since I am using EMT as my primary ground path?
Quote:


I know the code says that you need to run one in each conduit, but it doesn't really address if you just running the ground wire for extra safety and you already have the EMT as your primary path.

Thanks
Jamie
The Code just says that EMT is suitable for grounding, but if a ground wire is installed, it shall be sized by 250.122. Tests have shown that the conduit carries the majority of the fault current, even when a ground wire is installed. What the ground wire ensures is that if there is a fault, there won't be a dangerous arc from a loose fitting.

jamiedolan 11-16-2008 07:19 PM

Quote:

Originally Posted by InPhase277 (Post 185914)
The Code just says that EMT is suitable for grounding, but if a ground wire is installed, it shall be sized by 250.122. Tests have shown that the conduit carries the majority of the fault current, even when a ground wire is installed. What the ground wire ensures is that if there is a fault, there won't be a dangerous arc from a loose fitting.

Thanks for the info on sizing the grounding wire. No loose fittings here. I just went to Lowes and picked up that channel lock nut pliers. It's still a little tricky to grab onto them, but it give you some leverage and gets it really nice and tight.

I am going to run a ground wire as you suggest. I have a 500 foot spool of #12 I just bought... I should have got a spool of #10. oh well I'll use it up eventually.

Thanks
Jamie


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