Bathroom renovation - worth it to rewire?


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Old 05-06-10, 07:43 AM
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Bathroom renovation - worth it to rewire?

I'm in the middle of a complete bathroom renovation, I've gotten everything pretty stripped down and I'm at the point that I want to run an extra receptacle, move a light fixture, and replace the bathroom fan. The house is early 50s construction and wired with cloth-sheathed 2-wire NM cable (each individual wire is insulated with plastic), with receptacles connected to an external ground wire. The ground wire is only connected to a copper pipe, however, not all the way back to the panel. Luckily all the wire is 12-guage on a 20-amp breaker (surprisingly). The NM cable appears to be in reasonably good condition.

This brings me to my question: is it worth it to run a new, grounded 12-guage cable from the panel to serve the bathroom, or can I get away with just using the existing 2-wire as long as everything is GFCI protected? I realize code seems to say its fine to leave the ungrounded circuit as long as I have GFCIs, I just need to have the "no equipment ground" sticker on the faceplates. Is my interpretation of the code correct that this would still be okay even if I am adding a new receptacle, or does this exception apply only if you are just replacing an existing one?

Just looking to get an idea if anyone has been in this situation before... it'd be a bit of a pain to run a wire, but I found a path I could use to get it up to the second story. If there's no real reason to as long as the old wire is in good condition, though, then I'd be inclined to skip it.

Thanks in advance!
 
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Old 05-06-10, 07:49 AM
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Originally Posted by Auream View Post
I'm in the middle of a complete bathroom renovation, I've gotten everything pretty stripped down and I'm at the point that I want to run an extra receptacle, move a light fixture, and replace the bathroom fan. The house is early 50s construction and wired with cloth-sheathed 2-wire NM cable (each individual wire is insulated with plastic), with receptacles connected to an external ground wire. The ground wire is only connected to a copper pipe, however, not all the way back to the panel. Luckily all the wire is 12-guage on a 20-amp breaker (surprisingly). The NM cable appears to be in reasonably good condition.

This brings me to my question: is it worth it to run a new, grounded 12-guage cable from the panel to serve the bathroom, or can I get away with just using the existing 2-wire as long as everything is GFCI protected? I realize code seems to say its fine to leave the ungrounded circuit as long as I have GFCIs, I just need to have the "no equipment ground" sticker on the faceplates. Is my interpretation of the code correct that this would still be okay even if I am adding a new receptacle, or does this exception apply only if you are just replacing an existing one?

Just looking to get an idea if anyone has been in this situation before... it'd be a bit of a pain to run a wire, but I found a path I could use to get it up to the second story. If there's no real reason to as long as the old wire is in good condition, though, then I'd be inclined to skip it.

Thanks in advance!
If there is anywhere in the circuit that utilizes a ground, that ground must travel back to the panel. If after installation someone ran a ground wire, you're going to have to replace the wire feeding the bathroom to also include a ground. Having a floating ground that's not run back to the panel is dangerous because it implies that a ground path is present when it really isn't. Bite the bullet and rework your feed wire.
 
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Old 05-06-10, 08:25 AM
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Originally Posted by RHefferan View Post
If there is anywhere in the circuit that utilizes a ground, that ground must travel back to the panel. If after installation someone ran a ground wire, you're going to have to replace the wire feeding the bathroom to also include a ground. Having a floating ground that's not run back to the panel is dangerous because it implies that a ground path is present when it really isn't. Bite the bullet and rework your feed wire.
Thanks,

I forgot to mention that if I did leave the existing circuit in place, I'd remove the ground wire connected to the cold water pipe, and rely in the GFCIs for fault protection. Everything in the bathroom that I'd be touching (including the exhaust fan) would either be directly GFCI protected or fed off the load side of a GFCI receptacle. In that case, is it still worth it to re-wire? (I suspect the answer will still be yes but just looking for more input.)
 
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Old 05-06-10, 08:36 AM
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Originally Posted by Auream View Post
The house is early 50s construction and wired with cloth-sheathed 2-wire NM cable
Whenever this is exposed it should be replaced IMHO. The insulation was based on natural rubber, so after 50 years it has broken down significantly even if it looks okay. Newer wires roughly from the 60s on have synthetic insulation that holds up better, but still should be handled carefully to avoid cracking insulation.

This brings me to my question: is it worth it to run a new, grounded 12-guage cable from the panel to serve the bathroom
Yes.

I realize code seems to say its fine to leave the ungrounded circuit as long as I have GFCIs
This is only allowed for existing circuits when they are left as-is. The bathroom renovation requires upgrade to modern code.
 
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Old 05-06-10, 09:11 AM
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Originally Posted by ibpooks View Post
Whenever this is exposed it should be replaced IMHO. The insulation was based on natural rubber, so after 50 years it has broken down significantly even if it looks okay. Newer wires roughly from the 60s on have synthetic insulation that holds up better, but still should be handled carefully to avoid cracking insulation.
I don't think the wiring I have is based on natural rubber. This wire appears to be very similar to modern Romex other than the fact that it doesn't have a ground and the outer cover is cloth rather than plastic. The individual wires are still wrapped in plastic, unless its a very plastic-looking rubber?

This is only allowed for existing circuits when they are left as-is. The bathroom renovation requires upgrade to modern code.
That is what I suspected, which is what lead me to consider re-wiring. Sounds like that is going to be what I have to do. There were a couple ways I was considering getting a cable up from the basement to the second story, but it looks like the easiest might be through an old unused (completely disconnected from the HVAC system) heating duct. Since it isn't connected to anything, would it be okay to just run MC cable up through there, or am I going to have a problem because the cable isn't fastened to anything along the run? I was thinking it would essentially be like using a very large conduit, but since it isn't actually conduit (it's a 6" round duct) it may still be prohibited or the cable required to be fastened along the run which I obviously coudn't do, except at the entrance and exit points.
 
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Old 05-06-10, 01:35 PM
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Originally Posted by ibpooks View Post
This is only allowed for existing circuits when they are left as-is. The bathroom renovation requires upgrade to modern code.
what article are you referring to?
 
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Old 05-06-10, 03:05 PM
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Art. 406.3(D) is only for replacement of non-grounding receptacles, not installation of new boxes, devices and fixtures.

I don't think it would be a code issue if the OP left the bathroom circuit as-is and replaced with GFCI, but the stated goal was to add receptacle(s), move light fixtures and add a fan. In my mind that constitutes a rewiring of the whole bathroom which, if original to 1950, probably has only one receptacle and light fixture.
 
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Old 05-07-10, 05:26 AM
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Originally Posted by ibpooks View Post
Art. 406.3(D) is only for replacement of non-grounding receptacles, not installation of new boxes, devices and fixtures.

I don't think it would be a code issue if the OP left the bathroom circuit as-is and replaced with GFCI, but the stated goal was to add receptacle(s), move light fixtures and add a fan. In my mind that constitutes a rewiring of the whole bathroom which, if original to 1950, probably has only one receptacle and light fixture.
There was a bath fan added sometime after the original wiring, which was not GFCI protected despite being directly over the shower (maybe that was okay when it was installed?) Anyway, my plan involves changing that wire to come off of the load side of the GFCI outlet it is next to, moving over a light fixture by one stud bay to center it in the room, then drop a new GFCI protected outlet on the other side of the vanity.

If I were to re-wire, does anyone have input on my question above, regarding running MC cable through a disconnected heat duct?
 
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Old 05-07-10, 05:37 AM
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If it were me I would run a new circuit for the bathroom. As it sounds like the circuit is not grounded properly, the code does not allow ungrounded circuits to be extended. Running a new proper ground back to the panel is the same hassle as running a new cable and still leaves old cables in place that are nearing the end of their useful life.
 
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Old 05-07-10, 06:21 AM
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Originally Posted by Auream View Post
There was a bath fan added sometime after the original wiring, which was not GFCI protected despite being directly over the shower (maybe that was okay when it was installed?) Anyway, my plan involves changing that wire to come off of the load side of the GFCI outlet it is next to, moving over a light fixture by one stud bay to center it in the room, then drop a new GFCI protected outlet on the other side of the vanity.

If I were to re-wire, does anyone have input on my question above, regarding running MC cable through a disconnected heat duct?
The code does allow for a cable to be fished through areas where strapping is impossible, without requiring strapping. If the duct is truly abandoned and incapable of being reused, you can use it as a chase for your electrical. Strap the run as best you can and don't use it if any sharp edges are present to damage the Romex.
 
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Old 05-07-10, 08:21 AM
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I don't see why you couldn't use the abandoned duct. I would put some consideration into firestopping it once the wires are pulled. It's too big for caulk or foam, so I'd probably cut a cap out of sheet tin with a notch for the MC, screw it on the open end of the duct in the basement, then caulk or foam the smaller gaps.
 
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Old 05-07-10, 08:21 AM
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Originally Posted by RHefferan View Post
The code does allow for a cable to be fished through areas where strapping is impossible, without requiring strapping. If the duct is truly abandoned and incapable of being reused, you can use it as a chase for your electrical. Strap the run as best you can and don't use it if any sharp edges are present to damage the Romex.
The duct is completely disconnected, and has no real way of being re-used (nor is there a reason to, it terminated in a small closet in the master bedroom that has no reason to be conditioned).

There may or may not be sharp edges along the inside of the duct, that is why I was planning on using MC cable instead of Romex. Is there any reason you could think of not to use MC cable, other than it being a bit costly? I think I'll run romex in the basement until I get near the duct, put in a box to transition to the MC, then run the MC up to the second story to the bathroom. That way I can get away with only 50 feet of MC and not have to buy a 100+ foot roll.

Originally Posted by ibpooks View Post
I don't see why you couldn't use the abandoned duct. I would put some consideration into firestopping it once the wires are pulled. It's too big for caulk or foam, so I'd probably cut a cap out of sheet tin with a notch for the MC, screw it on the open end of the duct in the basement, then caulk or foam the smaller gaps.
Thanks, I was think about that as well, since the duct is standard 6" round I can just buy a premade 6" duct cap for a couple bucks, drill a hole through it for the wire and install a cable clamp and run the wire through it. It'll look much cleaner and firmly clamp the cable at the basement end.
 
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Old 05-07-10, 09:42 AM
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Originally Posted by Auream View Post
The duct is completely disconnected, and has no real way of being re-used (nor is there a reason to, it terminated in a small closet in the master bedroom that has no reason to be conditioned).

There may or may not be sharp edges along the inside of the duct, that is why I was planning on using MC cable instead of Romex. Is there any reason you could think of not to use MC cable, other than it being a bit costly? I think I'll run romex in the basement until I get near the duct, put in a box to transition to the MC, then run the MC up to the second story to the bathroom. That way I can get away with only 50 feet of MC and not have to buy a 100+ foot roll.
If it were me, I'd avoid MCAP or Corraclad, which are MC varieties which rely on the cable sheath as primary grounding method. It's not required, but I personally like having the ground wire and not relying upon the cable sheath as the ground path, particularly if I'm fishing a wire and it may snag and affect the sheathing. I'd also go straight to the panel, because I don't particularly care for extra j-boxes when not completely necessary. That said, your plan is completely up to code and my suggestions are above the required minimum.

Originally Posted by Auream View Post
Thanks, I was think about that as well, since the duct is standard 6" round I can just buy a premade 6" duct cap for a couple bucks, drill a hole through it for the wire and install a cable clamp and run the wire through it. It'll look much cleaner and firmly clamp the cable at the basement end.
If you do that, I'd very clearly label that duct as ABANDONED. If an inspector sees you enter a closed duct and it isn't clearly labeled, he probably won't like it.
 
 

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