NEC questions...

[miamicanes]

Suppose you have two or more outlets wired in parallel along a single circuit, with the boxes fed sequentially by a single supply that enters one side, and exits the other. Does the NEC have any particular requirement that those outlets, though wired in parallel, must be physically laid out in series along a single set of wires? Or, put another way, is there a limit to the number of physical boxes on a physical branch of their own that can "tap into" an existing branch inside the box of an outlet somewhere along it?

Here's a concrete example: Two outlets are wired along a single circuit. One is the last outlet on the branch, one is the penultimate outlet on the branch. A third outlet is added somewhere along the branch between them. THEN, one or more outlets are wired similarly on another wall, and tap into the branch inside the third outlet's box.

I'm fairly sure it would be officially OK to do it if the branch were to supply power to exactly ONE box (containing a single receptacle, or maybe two receptacles wired in parallel) located beyond the source, but I have my doubts about whether it's legal to create what's essentially a sub-branch feeding two or more separate boxes downstream from the tap. Is it allowed? If not, would it be OK if each outlet on the second wall had its own "home run" leading to the new (third) outlet so that technically each tap was feeding only a single box?

OK, now a tougher question. I know the NEC has rules governing how much free space is needed inside the box, and it becomes a VERY big deal with you're dealing with shallow boxes (1-1/4" is definitely shallow). Would it be OK to have a 1-1/4" double-gang box with two 2-outlet receptacles where the supply enters the box from a conduit on the right, connects to the right receptacle's top screws, the respective bottom screws of the two outlets are connected together (hot to hot, neutral to neutral), then the left receptacle's top screws connect to wires that exit the box to the left?

Assuming it's OK, would it STILL be OK if there were a second hot wire (switched) that passed through the box, but was not connected to either outlet (but required a small wire nut to connect the wire from the entering side to the wire on the exiting side)?

I'm pretty sure the answer would be an unambiguous "no", but how about if the top outlet of the left or right receptacle WERE connected to the switched wire, the tab connecting the top and bottom outlets of the receptacle were snapped, and a 4-wire pigtail for the unswitched "hot" line were needed... one in, one out, and one to each outlet?

Possibly making the whole thing moot... do 1-1/4" deep triple-gang boxes, and faceplates that reduce them to double-gang actually exist (and make the whole matter of trying to shoehorn a pair of outlets into a shallow double-gang box unnecessary)? I'm going to a real electrical supply store on Monday morning, but I'm trying to get an idea what to expect them to have compared to what they sell at Home Depot/Lowe's. In the HD/L universe, double-gang faceplates for triple-gang boxes don't seem to exist, period. But then again, in the HD/L universe, 1-1/4" deep boxes don't exist, either...

 

[personalt]

I am taking a leap that I understand your question. I think what you are asking is that is if you had 3 outlets on a single string could you 'T' off the middle outlet and run a new string of outlets. If that is your question then yes you can. You need to make sure you use the same size wire though as the original branch. Certainly dont use smaller wire and dont use bigger wire as it adds confusion and is against code. In my opinion the best way to this would be to tie the wires together outside the switch witha wire nut. Connect the black coming in with power, the two blacks heading out and a short peice of black wire togther with a wire nut. The small black you just added can then be attached to the swtich. Make sure you use the proper size, I would be using a red nut for that. Do the same with the white wire. If you had an outlet that you could backstab the wires, in theory you could hook a black wire up to each of the screws a and backstab the other but that really is half a**ed

For your second question, I dont think they make a 1 1/4" box.. The smallest is 1 1/2" except for a 1" swtich box which would never provide enough room for the wires you have. You need somthing wider that you can use a mudring to bring back down. This gives you a side pocket to make some connections. The smallest box like that appears to be 1 1/2" deep.

The NEC code for volume works on a point system. You add up the number of devices and wires and a certain size box is needed based on that count. It is based on the number of wires not how they are hooked up(except that all grounds together cou It is based on volume, so if you get an oversized box with a mudring

RACO is the big steel box company. They do make a 2 gang cover that fits a 3 gang box..
http://www.hubbellcatalog.com/raco/raco_da...11493,1682,8669

One issue that I see is that the mudring is 3/4". If you are using 1/2" dw you would need to set it back 1/4"
The second issue is that the smallest multigang box they seem to have is 1 5/8"
http://www.hubbellcatalog.com/raco/raco_da...,1858,9203,8850

You are going to not have enough depth... You are 3/8" short.

I thnk your best best is to go with a 4"x4" square box or better yet a 4 11/16"x 4 11/16" box. The problem you are going to find is that they start at 1 1/2" deep. Can you chip the block away at all? You are still a 1/4" short....

Here is a page that tells you how to calculate box volume
http://www.hubbellcatalog.com/raco/RACO_bo...p?FAM=RacoBoxes


I dont have time to do the math but a 4 11/16" allows 13 #12 wires and a 4" allows 9 #12 wires. You need to deduct 1 wire for each recepticle, one for all the grounds(together), one for each wire that passes through unbroken and then count up the rest of the wires and see if you make it. You also get to add a little volume for the mudring. But regardless, I think a 4 11/16" x 4 11/16" x 1 1/2" square is going to give you the best volume without having to chip away a lot.

The bad part is that I think you will have to chip away some no matter what box you use. Standard box sizes go from 1" to 1 1/2" and in 1" they only offer single switch boxes. They dont seem to offer boxes that are 1" and compatable with mudrings. If they did you could go with that mudring shown above, make all your connections in that side space and be all set. It wouldnt be easy but would be doable. But I dont think you will find anything more shallow then 1 1/2" in a box that supports a mudring

Suppose you have two or more outlets wired in parallel along a single circuit, with the boxes fed sequentially by a single supply that enters one side, and exits the other. Does the NEC have any particular requirement that those outlets, though wired in parallel, must be physically laid out in series along a single set of wires? Or, put another way, is there a limit to the number of physical boxes on a physical branch of their own that can "tap into" an existing branch inside the box of an outlet somewhere along it?

Here's a concrete example: Two outlets are wired along a single circuit. One is the last outlet on the branch, one is the penultimate outlet on the branch. A third outlet is added somewhere along the branch between them. THEN, one or more outlets are wired similarly on another wall, and tap into the branch inside the third outlet's box.

I'm fairly sure it would be officially OK to do it if the branch were to supply power to exactly ONE box (containing a single receptacle, or maybe two receptacles wired in parallel) located beyond the source, but I have my doubts about whether it's legal to create what's essentially a sub-branch feeding two or more separate boxes downstream from the tap. Is it allowed? If not, would it be OK if each outlet on the second wall had its own "home run" leading to the new (third) outlet so that technically each tap was feeding only a single box?

OK, now a tougher question. I know the NEC has rules governing how much free space is needed inside the box, and it becomes a VERY big deal with you're dealing with shallow boxes (1-1/4" is definitely shallow). Would it be OK to have a 1-1/4" double-gang box with two 2-outlet receptacles where the supply enters the box from a conduit on the right, connects to the right receptacle's top screws, the respective bottom screws of the two outlets are connected together (hot to hot, neutral to neutral), then the left receptacle's top screws connect to wires that exit the box to the left?

Assuming it's OK, would it STILL be OK if there were a second hot wire (switched) that passed through the box, but was not connected to either outlet (but required a small wire nut to connect the wire from the entering side to the wire on the exiting side)?

I'm pretty sure the answer would be an unambiguous "no", but how about if the top outlet of the left or right receptacle WERE connected to the switched wire, the tab connecting the top and bottom outlets of the receptacle were snapped, and a 4-wire pigtail for the unswitched "hot" line were needed... one in, one out, and one to each outlet?

Possibly making the whole thing moot... do 1-1/4" deep triple-gang boxes, and faceplates that reduce them to double-gang actually exist (and make the whole matter of trying to shoehorn a pair of outlets into a shallow double-gang box unnecessary)? I'm going to a real electrical supply store on Monday morning, but I'm trying to get an idea what to expect them to have compared to what they sell at Home Depot/Lowe's. In the HD/L universe, double-gang faceplates for triple-gang boxes don't seem to exist, period. But then again, in the HD/L universe, 1-1/4" deep boxes don't exist, either...

 

[miamicanes]

As much as I hate to admit it, I think you're right about the depth. I managed to buy four 4x4x1-1/4" boxes this morning, but I didn't think of the mudring issue until after I got home, and realized that I had another problem... the cable itself would need to have drywall removed at the point where it enters and exits the box, because the hole is 1/2".

At this point, I'm contemplating two possible solutions...

1. Try to figure out how to remove at least 3/4" of concrete behind the box... preferably in a way that won't egregiously violate building codes. It's possible that the prohibition only applies to water and drain pipes, but I'm under the impression that penetrating a party wall for services of any kind is taboo. How in god's name the original builder apparently got away with doing precisely that is beyond me. I know for a fact that the wall adjacent to the party wall in the kitchen and laundry room is framed with normal steel studs to create a few inches of space between the party wall and rear surface of the drywall for pipes.

2. Rip down the drywall from the upper half of the wall, too (I bought 6 sheets when I rented the truck from Lowe's, so I DO have enough to do it), screw a second set of 1x2 (3/4" deep) furring strips into the original ones (creating 1 1/2" behind the drywall instead of the current 3/4"), and hang the new drywall over THAT. As usual, this option presents problems, too. Adjacent to the upper right corner of the wall (on the upper left corner of the perpendicular wall) is an A/C vent. Right now, I have exactly enough room to run the new crown moulding to the wall with the vent and put a corner return... clearing the vent with about a millimeter to spare. If I move the wall 3/4", I'm going to have to do something REALLY weird/funky with the crown moulding and terminate it further from the vent to ensure that there's enough clearance left to remove the grill someday if necessary without having to tear down the crown moulding to do it. Wiretracks CM would come very much in handy at this point, but unfortunately it looks like the company that made them has quit. I'm also questioning the prudence of trying to hang an entire wall of drywall myself. The lower half? No problem. I can carry it to the right location, set it down on some shims, and screw it in. The upper half? Yikes. It's not so much that I think I can't do it, as it is a case of wondering whether I could actually do it myself and have it end up looking good, since getting that first screw in won't be fun or easy.

Come to think about it, how DO you break a hole through the solid side of a concrete block into the block's interior cavity?

Sigh. If I weren't so desperate to finish this project from hell, I'd try to get cast for an episode of "Over their head" on HGTV, because my living room is a perfect case study of a room that breaks just about every assumption home improvement books make about building construction (based on the 2x4 wood-framed norms of non-Florida America).

 

[personalt]

Are you a 1/4" short or 3/4" short. It sounded like you were looking for 1 1/4" deep boxes so I figured you were 1/4" short.

If you get a 4 11/16"x4 11/16" by 1 1/2" box you can get a 1/2"double gang mud-ring for it. The box goes a hair deeper then flush with face of stud.

That to me sounds like you only need a hair more then 1/4"

If that is the case I would do it the way I dado a peice of wood. I would take a 4" grinder with a diamond blade(like a tile blade) and cut groves in the area where the box goes. then I would take a chipping hammer and chip off the peices between the cuts.


If I had to take out 3/4" hole I would just cut a full hole.

If I cut a hole in fire wall I would wrap the box with a fire pad
http://www.grainger.com/Grainger/items/3BE63

then cut a hole with a ginder as close to exact size of the box plus pad as possible. I would use a grinder and a chipping hammer to do that. Caulk any gap between the fire pad and the concrete with fire caulk. Both the fire caulk and the fire pad expand during a fire to protect the wall.

This is certainly the best way to protect it. My concern would be the banging on the wall and would it piss of the neighbors

 

[miamicanes]

Up until this morning, I thought 1-1/4" deep boxes would solve my problem (3/4" furring depth + 1/2" drywall), but that was because I'd totally overlooked the mud-ring depth.

I DID think of another possibility, though... I wonder whether anyone makes semi-surface-mounted outlet boxes that are kind of like the WireMold starter boxes sold at Home Depot, but are *JUST* deep enough to mount over a 1-1/4" box in the wall and provide an area that's deep enough to meet the code requirements, and wouldn't look like crap mounted on the wall. Perhaps even disguised, so they just look like ornate, oversized, thick Decora-style faceplates. I'm guessing "probably not" since there are probably too few people with this problem to make a viable market, but it's probably worth exploring. If it weren't so cost-prohibitive, I'd think about designing one in AutoCAD and having them made by a service bureau with 3-D printer. But for what it would cost to make 4, I could probably pay someone to just do the job for me with conventional parts.

 

[Steve]

Maybe this might help stir some thoughts? Look at last post. Also, you could leave the top drywall in place, fix the bottom of the wall and then just add a second layer of drywall.

 

[dsiroky]

If you use steel boxes instead of the blue/orange plastic ones, don't forget that:

1) you need to ground the box (in addition to grounding the outlets in the box)

2) you need to use screw down style wire clamps on the high voltage wires as they enter/exit the box. This is to prevent tension on the wires (for example by someone pulling the other end) from fraying the sheathing on the wire and causing a short/fire.

You also want to make sure the box itself is securely screwed to a stud. They don't always have mounting holes in the right spot so you might need to drill some through the steel box.

 

[miamicanes]

Maybe this might help stir some thoughts? Look at last post. Also, you could leave the top drywall in place, fix the bottom of the wall and then just add a second layer of drywall.

Well, if I'm going to deepen the wall, I'd rather just get rid of all the paper-backed drywall from that wall, and know that I have at least one wall that will never, ever harbor significant amounts of mold again

From the link at gardenweb, it appears that I'm not the first person to encounter a shallow wall after all. Unfortunately, it looks like most of them ended up doing exactly what I came up with as "Plan B" -- rip out the drywall, make the faux studs/furring strips deeper, and put up new drywall. Sigh.

Question for anyone who might happen to be in Florida and know... Home Depot has two kinds of treated 1x2 furring strips, both of which are the same exact price. One variety is very slightly greenish-yellow. The other is almost a neon greenish-blue and labeled "borate-treated". Intuitively, I want to think that the borate-treated strips would be ideal, because they'd also be toxic to any insects (like roaches) that made their way into the wall and came into contact with them. However, I have a major hunch that using THOSE as furring strips would be against the law (even though blowing borate powder into the wall through an opening between the drywall and outlet would be perfectly legal).

 

[Steve]

Question for anyone who might happen to be in Florida and know... Home Depot has two kinds of treated 1x2 furring strips, both of which are the same exact price. One variety is very slightly greenish-yellow. The other is almost a neon greenish-blue and labeled "borate-treated". Intuitively, I want to think that the borate-treated strips would be ideal, because they'd also be toxic to any insects (like roaches) that made their way into the wall and came into contact with them. However, I have a major hunch that using THOSE as furring strips would be against the law (even though blowing borate powder into the wall through an opening between the drywall and outlet would be perfectly legal).

Most of the problems with PT wood I believe is dust. You have to be very careful in cutting it and inhaling the dust. You would have to know what the exact chemicals in the other PT wood were to compare. But I think borates are probably safer (just guessing without knowing the other compounds). Here is the MSDS for borate treated wood (all manufactures I would think are similar). Find out the other wood chemical(s) and pull the MSDS for them. But this borate treated wood does not seem too bad. Borates are also used in swimming pools to buffer pH and control algae, but there are caution about drink the pool water (especially animals) if concentrations exceed 30ppm. I have always thought about using that new synthetic wood where PT is needed, it would certainly hold up as well if not better, but I'm not sure about off-gassing, etc of the plastics.

Edit: Found this...

Borates may be better
Not all pressure-treated lumber is copper-based. Borate-based treatments are also effective at stopping bugs, mold, and rot. Borate lumber treatments have low toxicity levels for people and pets. Borate taken into the body doesn't build up like heavy metals do; our bodies excrete what they don't need.

Borate pressure-treated wood has excellent to outstanding corrosion resistance to common metals, according to standards established by the AWPA. No special fasteners or flashings are required.

Lumber treated with disodium octaborate tetrahydrate (DOT) historically has been used in protected, not exposed, locations because borate leaches from wood when the wood gets wet.

But studies show that borate-treated lumber doesn't leach as much as its reputation suggests.

And borate treatments are getting better. Wood Treatment Products Inc. (www.eswoodtreatment.com) has developed a way to fix borate into lumber better. EnviroSafe Plus is the brand name of this turbo-borate, and it has tested well for borate retention, noncorrosiveness, fire suppression, and nontoxicity of smoke.

I would definitely go with borates over copper based if those were the 2 choices...

 

[miamicanes]

Well, the drywall is now completely gone from the wall. Happily, I didn't find any new mold, so I feel a lot better about leaving the other 3 walls with their original drywall on top.

Here's something that strikes me as REALLY WEIRD. I just got back from the Electrical supply store. I bought a 4-gang mudring, and a 6-gang box to screw it into. According to the guy who works there, there are mudrings to reduce a square box to single-gang, a 4-gang box to 3-gang, and a 6-gang box to 4-gang, but NO SUCH THING as a mudring to reduce a 3-gang box to 2-gang. Apparently, it's somehow legal to mount a pair of receptacles in a 4x4x1-1/2" box, even though logically it seems weird since every other scenario seems to involve an N-gang mudring over a N+{1..3}-gang box.