quick question on emt conduit

[usmc_noma]

so i've begun to wire in some extra outlets in my attached garage. i've already added outlets to the side that's unfinished, and now i need to start the side that leads into the house.

since the side against the house has drywall covering the studs i've decided i want to go surface mount running conduit to a four outlet gang box using 1/2" emt. before i do this i've got a few questions.

1st is...i know i should ground the emt, but how do i go about this? i'll have 12/2 romex from the breaker to the outlet. i'm pretty sure i should use a 12ga green ground wire too. where to i connect this in the gang box, and in the main panel? the emt will only be running from the breaker wall to the gang box with a few 90* bends. it will not be connected to the breaker box.

2nd ?? is...the emt will be running/touching under flex conduit. it will also be running/maybe touching my a/c vent system since it sits close to the wall the conduit will be running along. will this cause any additional problems?

3rd?? is...am i better off just running pvc along the wall instead of emt? i'd rather go emt but will go pvc if it's safer.

thanks!

 

[walrus]

You bond it by using a steel box, land a ground on the steel box, tighten the lock nuts on the emt and its grounded(really bonded)

 

[slamed tudor]

Thats true but is the box/conduit is not conected to the panel then there will be no ground. This is a very simple and easy fix. If your receptacle circut is only a two wire to begin with then the rest of the outlets on the circut have to remain two wire. NEC article 406 states that a gfci recpt can be put in where there is not a ground present. As for running the conduit along the a/c i doubt if you will ever have problems. As long at the conduit is not in the a/c duct, then this would be against code. Now back to the finished wall, why dont you just use cut in boxes and go in the attic and drill the top plate and fish the wall with romex? This would look cleaner, If your using romex 12-2 then there will be a bond wire in the sheathing. The bare copper wire is the bond.

 

[mrb]

why are you running romex in the conduit? Why not just run conduit and thhn wires in it?

 

[pipehack]

why are you running romex in the conduit? Why not just run conduit and thhn wires in it?

Thinking the same thing. Do that dude.

 

[nadogail]

1. 12-2 NM Cable has a ground conductor included & outlet boxes have 10-32 threaded holes, run the bare ground wire under a screw threade into the hole. Connect the ground conductor to each receptacle (outlet).

2 There might be some noise caused from vibration of the ducting. Vibrating contact of two pieces of metal might possibly wear a hole in one or both of them. Either solidly fasten the conduit to the ducting or isolate it.

3 EMT will give you mechanical protection, PVC breaks when hit

 

[usmc_noma]

yea, the 12/2 romex has a ground included. i was basically wondering if i can run the ground wire to the two separate outlets, like normal, and run a ground wire from the 2nd outlet directly to the metal gang box. i don't see why it wouldn't work to ground the box to the outlets. this would make the metal box and emt all grounded wouldn't it?

i just checked the clearance behind the metal a/c unit and it's good to go. i've got about 1" to 1.25" behind to clear the 1/2" conduit. the only part that would touch any other metal is where it would run under the flex conduit for the a/c.

the reason i'm using romex is because it's what i had left over from adding in to the other side of the garage. no reason to get more wire if i already have some. also, my house is a 2story hence the reason for going surface mount. i'm not running wire up 2stories to have it come back down. imo, the emt will keep it neat looking.

 

[Aceman]

This is a very simple and easy fix. If your receptacle circut is only a two wire to begin with then the rest of the outlets on the circut have to remain two wire. NEC article 406 states that a gfci recpt can be put in where there is not a ground present.

You can't extend a 2-wire ungrounded circuit by simply adding a GFI at the beginnning. 250.130

As for running the conduit along the a/c i doubt if you will ever have problems. As long at the conduit is not in the a/c duct, then this would be against code.

What code is that?

i was basically wondering if i can run the ground wire to the two separate outlets, like normal, and run a ground wire from the 2nd outlet directly to the metal gang box. i don't see why it wouldn't work to ground the box to the outlets. this would make the metal box and emt all grounded wouldn't it?

Yes, typically the ground is looped around the ground screw in the box first and then ran to the devices. But, as long as everything is grounded, it really makes no difference.

 

[usmc_noma]

Yes, typically the ground is looped around the ground screw in the box first and then ran to the devices. But, as long as everything is grounded, it really makes no difference.

thanks!
now that i have my answer about the ground. does it matter that the emt will touch the flex conduit? that won't cause problems with the grounding at all will it?

 

[slamed tudor]

No it wont

 

[slamed tudor]

ACEMAN, its legal to put a gfci in a non grounded circut and downstream with three prong recpts after that. I think you need to check out article 406.3a-e!

 

[Charles (in GA)]

ACEMAN, its legal to put a gfci in a non grounded circut and downstream with three prong recpts after that. I think you need to check out article 406.3a-e!

If the ground prong of the three prong receptacles you speak of, are not grounded back to the panelboard, then you effectively have no ground, and the receptacles have to be labeled "No Equipment Ground" and also "GFCI Protected". Also note that the ground of the three prong receptacles may NOT be connected together (or to anything) unless they are all carried back to the panelboard ground bar.

Charles

 

[slamed tudor]

Yes your right charles, I should of explanied myself more instead of just giving the article #. But in this article that is exactly what is stated. Again sorry i didnt make myseld more clear.