Grounding question. Can I ground a 2 wire...

[tolken4]

Can I ground a 2 wire circuit to a near by grounded metal box? The grounded circuit is 15 amp, the non grounded circuit is a 20amp.

If this is ok, am I correct in assuming that only outlets/boxes down stream from the ground will be grounded?

Basically I am putting a gfci and a couple of outlets into a bathroom on an existing 20amp circuit with more than enough capacity, but it is not grounded. I know the gfci will take care of this in a way, but I would feel better having the true ground in case of GFCI failure. However, there is a 15amp circuit which is real close by that I could pigtail a ground into where I am adding my outlets.

Thanks,

 

[tolken4]

Not to be impatient, but anyone got a yes or no on this one??? I was hoping to close the wall up tonight and this is the last thing to do.

 

[oleguy]

not to be impatient, but anyone got a yes or no on this one??? I was hoping to close the wall up tonight and this is the last thing to do.

the grounding conductor needs to be the same size as current carring conductors.#12 requires a #12 ground.

 

[sberry]

If you got gfci don't bother unless you specifically need grounded circuit for special equipment. There are a lot of rules about adding grounds, if I wanted to do it I would likely pull a new wire although you are allowed to ground individual outlets with extra wire, ideally running along with the circuit conductors and you cannot daisy chain this wire which would need to go back to the panel.

 

[tolken4]

Thanks for the replies!

My wish for the ground was the bathroom (possible water) application. Liked the idea of the added security in the rare chance that the GFCI failed.

One more if I may... 20amp circuit can or cannot have 15amp plugs and switches on it? My local guy just said no, but everything else I read says yes, if it has more than one device on it.

Understand, I am not just trying to skirt the rules, here, in fact the opposite. My rookie mind tells me that if I put a 15amp device on a 20 amp circuit, it is really not protected at all?

So, when code states that a bathroom requires a dedicated 20amp breaker/circuit, and I then put a 20 amp receptical on said circuit, and plug a device that is only needing to be 15amp. How is that device protected other than what built in breaker it may or may not have such as a incandescent light having a a built in fuse if you will.

 

[bimmer1980]

keep in mind that for a GFI to work properly it needs a good ground. Ideally that ground is tied all the way back to the ground in the panel. That may even be a NEC requirement.....

Basically, the GFI looks at the amperage on the hot and the neutral. If they differ, it instantly grounds out the outlet. So you need a good ground for a GFI to transfer the fault current.

 

[walrus]

Basically, the GFI looks at the amperage on the hot and the neutral. If they differ, it instantly grounds out the outlet. So you need a good ground for a GFI to transfer the fault current.

Why does the NEC allow GFI recepts on old 2 wire circuits if you need a good ground for them to work?

 

[oleguy]

Thanks for the replies!

My wish for the ground was the bathroom (possible water) application. Liked the idea of the added security in the rare chance that the GFCI failed.

One more if I may... 20amp circuit can or cannot have 15amp plugs and switches on it? My local guy just said no, but everything else I read says yes, if it has more than one device on it.

Understand, I am not just trying to skirt the rules, here, in fact the opposite. My rookie mind tells me that if I put a 15amp device on a 20 amp circuit, it is really not protected at all?

So, when code states that a bathroom requires a dedicated 20amp breaker/circuit, and I then put a 20 amp receptical on said circuit, and plug a device that is only needing to be 15amp. How is that device protected other than what built in breaker it may or may not have such as a incandescent light having a a built in fuse if you will.

to answer your question on your rookie mind,a 20 amp ckt has a max of 20 amps.not every device draws the ckt max.just beacause you have a 15,20 or greater ckt,doesn't mean you have to only use it to full capicity.the 15 amp device IS protected on the 20 amp.the 15 amp recep is fine on a 20 amp ckt.
also if the gfci outlet fails the ground won't matter anyway.

 

[sparky1562]

keep in mind that for a GFI to work properly it needs a good ground. Ideally that ground is tied all the way back to the ground in the panel. That may even be a NEC requirement.....

Basically, the GFI looks at the amperage on the hot and the neutral. If they differ, it instantly grounds out the outlet. So you need a good ground for a GFI to transfer the fault current.

No, it does not need a ground. It opens the circuit in the device. It does not ground anything out.

 

[sparky1562]

One more if I may... 20amp circuit can or cannot have 15amp plugs and switches on it? My local guy just said no, but everything else I read says yes, if it has more than one device on it.

So, when code states that a bathroom requires a dedicated 20amp breaker/circuit, and I then put a 20 amp recepticle on said circuit, and plug a device that is only needing to be 15amp. How is that device protected other than what built in breaker it may or may not have such as a incandescent light having a a built in fuse if you will.

The NEC says that a single device on a circuit has to match the circuit ampacity, IE, A 15 amp dedicated device, 15 amp circuit, 20 amp dedicated device, 20 amp circuit. Multiple devices on a circuit, two or more 15 amp devices and the circuit can be 20. You will get arguments if a duplex is one or two devices. I consider it one, have seen some inspectors see it as one, but some say its two on one strap.

The circuit is not protecting the appliance. Now if some one cuts a 20 amp plug off and puts a 15 amp plug on to plug it into a 15 amp outlet, get the fire department on standby!

 

[tolken4]

Awesome, thank you everyone fore the input...

I can confirm a GFCI does not ground out, it see a change in the electric field and opens the circuit.

I had also read on many forums the part about as long as more than one device are on a circuit you could use 15amp. I was suprised the local guy said no.

So, if it were your house...

Would you?
1. Slap a GFCI on the 20 amp circuit and call it good?
2. Rerun all the wire to ground it back to the panel?
3. Leave all the wire alone and run a seperate dedicated 20amp for the bath. Might actually be easier than tracking down all the old stuff to make sure I don't miss anything.

Also, there are multiple devices on this circuit. Would you have any issues with 15amp devices including 15amp gfci with "20 amp passthru" ratings.

Thanks again, I really appreciate the help and this is my last addon question. Well, unless I think of another one

 

[Charles (in GA)]

You will get arguments if a duplex is one or two devices. I consider it one, have seen some inspectors see it as one, but some say its two on one strap.

Article 100, Receptacle. A receptacle is a contact device installed at the outlet for the connection of an attachment plug. A single receptacle is a single contact device with no other contact device on the same yoke. A multiple receptacle is two or more contact devices on the same yoke.



Charles

 

[Charles (in GA)]

Awesome, thank you everyone fore the input...

I can confirm a GFCI does not ground out, it see a change in the electric field and opens the circuit. If current out does not equal current in, then the device trips open.

I had also read on many forums the part about as long as more than one device are on a circuit you could use 15amp. I was suprised the local guy said no. Apparently he is not familiar with the code or just likes to be in charge

So, if it were your house...

Would you?
1. Slap a GFCI on the 20 amp circuit and call it good? Would not have any qualms about doing this, just label it "no Ground"
2. Rerun all the wire to ground it back to the panel? Lot of work for little benefit.
3. Leave all the wire alone and run a separate dedicated 20amp for the bath. Might actually be easier than tracking down all the old stuff to make sure I don't miss anything. Actually a very good idea

Also, there are multiple devices on this circuit. Would you have any issues with 15amp devices including 15amp gfci with "20 amp passthru" ratings. None at all. If the GFCI cannot pass thru the full 20 amps, and you have a 20 amp breaker and mutiple loads downstream of it that equal 20 amps, what do you think would happen to the GFCI?

Thanks again, I really appreciate the help and this is my last addon question. Well, unless I think of another one

Charles......

 

[oleguy]

Awesome, thank you everyone fore the input...

I can confirm a GFCI does not ground out, it see a change in the electric field and opens the circuit.

I had also read on many forums the part about as long as more than one device are on a circuit you could use 15amp. I was suprised the local guy said no.

So, if it were your house...

Would you?
1. Slap a GFCI on the 20 amp circuit and call it good?
2. Rerun all the wire to ground it back to the panel?
3. Leave all the wire alone and run a seperate dedicated 20amp for the bath. Might actually be easier than tracking down all the old stuff to make sure I don't miss anything.

Also, there are multiple devices on this circuit. Would you have any issues with 15amp devices including 15amp gfci with "20 amp passthru" ratings.

Thanks again, I really appreciate the help and this is my last addon question. Well, unless I think of another one

#3.if you have good access I would run a new ckt.in the code,article 406.3(d)(1),(2),(3).take a look.

 

[sparky1562]

Article 100, Receptacle. A receptacle is a contact device installed at the outlet for the connection of an attachment plug. A single receptacle is a single contact device with no other contact device on the same yoke. A multiple receptacle is two or more contact devices on the same yoke.



Charles

Yes I know, but I have had inspectors, the old Authority having juristiction, say they don't care what the definition says.

 

[tolken4]

Thanks everyone for the help!