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Old 05-17-2013, 04:42 PM   #16
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Is it necessary to ground a ceiling box?


Quote:
Originally Posted by amakarevic View Post
Here is what I had rigged up before I was told I needed a box with braces. Feels darn sturdy. But is it still against the code?

P.S.: never mind the lack of wire nuts, this is just a temporary hack

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Originally Posted by tylernt View Post
It's legal if you screw the fan into the 2x4 and not just hang it from the box.

I think there is some clarification that needs said ...

when you screw the light bracket onto the box a regular box uses #8 screws ... a FAN RATED BOX uses #10 screws ... ...Look close at the pic I posted or here look at this one ...

see on the left side there is a STUD with threads .. that is for the fan bracket to box #10 screws ( you can only see one cause the cover is there ....)

but there are the #8's in case you want to not use a fan and can just put a fixture there ...







SO there are 2 parts to the FAN box the MOUNTING and the bracket screws

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Old 05-17-2013, 05:13 PM   #17
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Is it necessary to ground a ceiling box?


I screwed the box to this cross piece of 2x4 using 1.5" #10 Simpson screws. Those things are sturdy.
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Old 05-17-2013, 06:12 PM   #18
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Is it necessary to ground a ceiling box?


I would not trust a screw that short to hold a fan for any length of time. Screws to hold fan brackets to wood are normally around 4".
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Old 05-17-2013, 06:42 PM   #19
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Is it necessary to ground a ceiling box?


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I would not trust a screw that short to hold a fan for any length of time. Screws to hold fan brackets to wood are normally around 4".
so that means that they need more thickness to be attached than a regular 2x ceiling beam?
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Old 05-17-2013, 07:34 PM   #20
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Is it necessary to ground a ceiling box?


Just go buy the brace at HD or Lowes. You'll have it done in 5 minutes.
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Old 05-17-2013, 08:19 PM   #21
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Is it necessary to ground a ceiling box?


Regarding the ground wire question the OP posted originally, I also would appreciate some clarification.

Why does he need a ground screw in that metal box if that box itself is not grounded to somewhere?

For example in my house where all the boxes are metal and interconnected with rigid conduits (old ones) and EMT conduits (new ones), I would normally just use the green screw to the metal box and do away with feeding green wires.

However on some ceiling fixtures where I used MC cables, since MC cables cannot be relied upon for ground I would then feed the green wires through the MC conduits and in that case I don't need the green wire.

In the OP's pictures if he looks like he has a 12/2 MC cable connected to it should he connect the green wire of the fixture to the green wire of the MC cable (assuming that green wire goes somewhere that's grounded). To me it looks like that ceiling box is all by itself not grounded so what good is it to ground the fixture to that metal box?

Or may be my understanding is flawed?

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Old 05-17-2013, 08:37 PM   #22
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Is it necessary to ground a ceiling box?


Miami, your logic is not flawed. If the original wiring is not grounded neither will any of the new wiring. The NEC has a prohibition against extending ungrounded wiring to prevent that scenario.
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Old 05-17-2013, 09:05 PM   #23
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Is it necessary to ground a ceiling box?


Thanks Jim.



So looking at the ceiling box, it has three MC cables connected to it, so assuming one of the three leads to somewhere that's grounded, the way I would do it is to just tie all three green wires along with his fan fixture green wires together. I fail to see what a green screw to the box in that situation would do, unless all the green wires are screwed to that one screw as well.
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Old 05-17-2013, 09:27 PM   #24
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Is it necessary to ground a ceiling box?


Type MC cable has an insulated grounding conductor. The sheath is not the ground. The grounding conductor needs to connect to the box to ground it.

All the grounds should be connected together and the the box if metallic.
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Old 05-17-2013, 09:35 PM   #25
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Is it necessary to ground a ceiling box?


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Originally Posted by miamicuse View Post
Thanks Jim.



So looking at the ceiling box, it has three MC cables connected to it, so assuming one of the three leads to somewhere that's grounded, the way I would do it is to just tie all three green wires along with his fan fixture green wires together. I fail to see what a green screw to the box in that situation would do, unless all the green wires are screwed to that one screw as well.
Miami, you hit the keywords above, in bold red

If one of the wires led to a ground, then we would simply tie all the greens together, with a tail to the green screw in the box.

Make sense?
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Old 05-18-2013, 01:58 AM   #26
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Is it necessary to ground a ceiling box?


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Miami, you hit the keywords above, in bold red

If one of the wires led to a ground, then we would simply tie all the greens together, with a tail to the green screw in the box.

Make sense?
Yes.

EXCEPT ( I know...) for me, the way I do it, I would tie all the greens together, but I may not attach a tail to the green screw in the box.

IF I know for sure, that one of the green wires I am tying together, comes from an upstream metal box, and in that box, that green wire is attached to the green screw in that metal box, then I may not use a tail in the current box, because in my mind, one of the green wires I am tying together is already tied to a green screw, just not in this box. Now this is not what I normally do, as since in my case I used rigid or EMT conduits I don't pass green wires around and will use the green screw to each box. But when I run a MC cable from say box 42 to a ceiling box 43, I will attach the green wire to box 42 with a green screw, but at box 43, I just connect the green wire from box 42 to the fixture green wire, but I don't put a tail to a green screw in box 43. For me I do not see an advantage to use an additional tail there if that box is the end of a run. Now if that box jumps to other boxes, then I may use a tail to just ground that box.
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Old 05-18-2013, 04:42 AM   #27
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Is it necessary to ground a ceiling box?


Quote:
Originally Posted by miamicuse View Post
IF I know for sure, that one of the green wires I am tying together, comes from an upstream metal box, and in that box, that green wire is attached to the green screw in that metal box, then I may not use a tail in the current box, because in my mind, one of the green wires I am tying together is already tied to a green screw, just not in this box.
But every metal box needs to be bonded to ground.

I think I'm following your logic, but I think the logic is flawed. Do you think that because an upstream box is bonded, that the next box (downstream) will be? Are you thinking that we're creating redundant grounds? If so, I don't see that.
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Old 05-20-2013, 10:15 PM   #28
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Is it necessary to ground a ceiling box?


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Originally Posted by sirsparksalot View Post
But every metal box needs to be bonded to ground.

I think I'm following your logic, but I think the logic is flawed. Do you think that because an upstream box is bonded, that the next box (downstream) will be? Are you thinking that we're creating redundant grounds? If so, I don't see that.
I think I am getting a better idea from this conversation.

So basically EVERY METAL BOX needs to be bonded to ground. I was operating under the assumption that EVERY DEVICE need to be connected to ground, and the reason you ground the box is just a convenient way to ground the device.

In my case since my old house raceway is rigid conduits and EMT, all boxes are grounded. Therefore I do not use a green screw for every box. I think 90% of the time I do use one. An exception example would be a wall with a back to back metal box, with outlets in each, facing opposing rooms, most times I will use one green screw on one box, and pass a green wire to the other box for grounding. The two boxes connected via a very short piece of nipple.

However, I do use MC cables in some cases for recessed lights in the ceiling, and the way I normally do it is to run the conduits to the attic, and somewhere near the hatch opening I will have a metal junction box. From the metal junction box I will send out the MC cables to the ceiling box locations, for fans, for recessed lights etc...now, these ceiling metal boxes are not grounded because the outer sheath of the MC cables do not qualify as grounding conductors, so what I normally do is to just connect the green wire from the MC cable to the green wire of the actual device but I do not use a green screw to the box.

From what you are saying, I need to ground that metal box as well. That means I need to connect the green wire from the MC cable, the green wire from the device and a pigtail to the green screw of the box together, CORRECT?

If this is the case, I would need to go back and check all my ceiling boxes to make sure I did them right.

Which lead to another question. Let's say I have a metal junction box that USED TO have a device that is now canceled. However I have wires going into and out of that box. The device that was there was an outlet so now I just connect the incoming hot/neutral wires to the outgoing hot/neutral wires. My question in two parts.

(A) If that cancelled metal box has a rigid conduit in and rigid conduit out, the box is already grounded, no need to feed a green conductor, no need for a green screw in that cancelled box. CORRECT?

(B) If that cancelled metal box has a 12/2 MC cable in, a 12/2 MC cable out, that metal box is not grounded, therefore the green wire connection in that box should have a pig tail added and tied to a green screw to the box. CORRECT?

If so I think I get it now. Thank you.

If not, well, I think I am in trouble.
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Old 05-21-2013, 01:39 AM   #29
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Is it necessary to ground a ceiling box?


If it can carry current, it needs to be bonded.

That means: Box and Device gets grounded.

No, it's not just a convenient way to ground a device. In fact, you can't rely on the yokes of most devices to even give a proper ground to the box.

It's just not that difficult, or time consuming to make a pigtail and terminate it correctly.

When possible, I use the Carlon Blues to avoid the issue all together. But if you already have an existing metal box, then ground it.

Hope that helps.

Quote:
Originally Posted by miamicuse View Post
I think I am getting a better idea from this conversation.

So basically EVERY METAL BOX needs to be bonded to ground. I was operating under the assumption that EVERY DEVICE need to be connected to ground, and the reason you ground the box is just a convenient way to ground the device.

In my case since my old house raceway is rigid conduits and EMT, all boxes are grounded. Therefore I do not use a green screw for every box. I think 90% of the time I do use one. An exception example would be a wall with a back to back metal box, with outlets in each, facing opposing rooms, most times I will use one green screw on one box, and pass a green wire to the other box for grounding. The two boxes connected via a very short piece of nipple.

However, I do use MC cables in some cases for recessed lights in the ceiling, and the way I normally do it is to run the conduits to the attic, and somewhere near the hatch opening I will have a metal junction box. From the metal junction box I will send out the MC cables to the ceiling box locations, for fans, for recessed lights etc...now, these ceiling metal boxes are not grounded because the outer sheath of the MC cables do not qualify as grounding conductors, so what I normally do is to just connect the green wire from the MC cable to the green wire of the actual device but I do not use a green screw to the box.

From what you are saying, I need to ground that metal box as well. That means I need to connect the green wire from the MC cable, the green wire from the device and a pigtail to the green screw of the box together, CORRECT?

If this is the case, I would need to go back and check all my ceiling boxes to make sure I did them right.

Which lead to another question. Let's say I have a metal junction box that USED TO have a device that is now canceled. However I have wires going into and out of that box. The device that was there was an outlet so now I just connect the incoming hot/neutral wires to the outgoing hot/neutral wires. My question in two parts.

(A) If that cancelled metal box has a rigid conduit in and rigid conduit out, the box is already grounded, no need to feed a green conductor, no need for a green screw in that cancelled box. CORRECT?

(B) If that cancelled metal box has a 12/2 MC cable in, a 12/2 MC cable out, that metal box is not grounded, therefore the green wire connection in that box should have a pig tail added and tied to a green screw to the box. CORRECT?

If so I think I get it now. Thank you.

If not, well, I think I am in trouble.
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Old 05-21-2013, 10:52 AM   #30
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Is it necessary to ground a ceiling box?


Can't tell from pic but aluminum MC and direct bearing setscrew connectors do not mix.

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