Pancake "box"

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jeff43222

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I went on an estimate today and encountered something I'd never seen before. This was in a 1920s house, which describes most of the houses I work in. Instead of the usual pancake box crammed with cloth-covered wiring, what was there instead was something that looked like a pancake box, but it had no sides. It had the usual KOs and holes for mounting, but it also had a screw hole and a notch like you would expect for a cover plate. There were several of these throughout the house. It sorta looked like what you would get if a pancake box and a flat round cover plate had kids.

Has anyone seen anything like this before?

The HO wants me to install new lights and ceiling fans, but I don't see how I can do it legally with these weird plate/boxes. I've had inspectors in the past grandfather in pancake boxes that were in violation of the box fill rules by suggesting a light fixture with a spacious base, but I think mounting a new light fixture on the weird plate/box would be pushing it.
 
jeff43222 said:
Has anyone seen anything like this before?

Yeah, I have a small assortment of them that I've had to remove over the years, for precisely the same reason you're going to have to remove them.

You didn't find any live gas lines poking through them? Lucky you. :)
 
I thought about the gas line idea, as I've come across boxes like this that were retrofitted. I did smell some gas, but I'm pretty sure it was due to the homemade chili my girlfriend fed me recently. :D

Replacing these plate/boxes is not going to be easy. They're in the plaster/lath ceiling of rooms that have finished rooms above them, so no attic access. I've found that pancake boxes are often screwed right to the joists, so there's no place for a standard box to be recessed. I was thinking of using a saddle box, but I'm concerned about the condition of the cloth wiring and trying to push all eight wires through the limited number of openings.

Basically, the job looks like an expensive nightmare.
 
jeff43222 said:
I did smell some gas, but I'm pretty sure it was due to the homemade chili my girlfriend fed me recently. :D

:)

jeff43222 said:
Replacing these plate/boxes is not going to be easy. They're in the plaster/lath ceiling of rooms that have finished rooms above them, so no attic access. ..........
Basically, the job looks like an expensive nightmare.

I feel your pain. It's the ceilings on the first floor with beautiful old oak floors above them where you always seem to run into this sort of situation.

You might get lucky and find the "box" was mounted to a piece of 1x spanning two joists. Almost all of the ones I've run into were done that way, either because they had gas nipples poking through them or else because the k&t was running parallel through the same joist space.

But the ones that weren't mounted between joists were, well, you know...
 
mdshunk said:
Hey, I've got just the box for you, brother.... It's a lifesaver in your situation. It mounts right on the surface, but you can't tell because it's embedded in a medallion of sorts. Slick as a whistle. (6.1 cubic inches)
http://www.aifittings.com/n_3.htm
Not too shabby! Only restriction is the volume: 6.1^2". Just enough for a 14-2 w/g, not including canopy.
 
LarryFine said:
Not too shabby! Only restriction is the volume: 6.1^2". Just enough for a 14-2 w/g, not including canopy.
Yep... it's been so handy for me, I've been carrying one on the truck. Beats my previous method for those instances.... a round Wiremold box. Normally if you're using one of these for old work, it's just a couple of #14 K&T's or a #14 ungrounded romex. Add a couple of federal bushings for K&T or a the supplied flush NM connector for an old romex, and you're in business.

Note- I don't work for Arlington, but they do make some of the neatest crap. I'm just a regular electrician.
 
Chances are that the house was wired with AC cable and those plastic Arlington boxes won't work.
 
infinity said:
Chances are that the house was wired with AC cable and those plastic Arlington boxes won't work.
AC cable? In a house? Is that something peculiar to the midwest during a certain era? Never seen it in a dwelling here in my market, during any time period. If I ran into it, I'd spin on a bond bushing. Wouldn't that suit to originate an EGC tail in the box?
 
AC wire was common around here in dwellings for a certain period of time. (40's-50's I think) If you break into the sheath in the middle of the run, you might be suprised how well the insulation has held up. Its the termination points that degrade really bad (of course!):mad:
 
mdshunk said:
Hey, I've got just the box for you, brother.... It's a lifesaver in your situation. It mounts right on the surface, but you can't tell because it's embedded in a medallion of sorts. Slick as a whistle. (6.1 cubic inches)
http://www.aifittings.com/n_3.htm
Looks cool, but 6.1" isn't going to come close to what I will need to house all those wires. Like most of the pancakes I deal with, there are four KOs, each with two cloth-covered wires coming through them. Realistically, I'd need an octagonal box 2 1/8" deep just to be able to fit all of them in.
 
mdshunk said:
infinity said:
Chances are that the house was wired with AC cable and those plastic Arlington boxes won't work.
AC cable? In a house?
Yes, AC, as in BX. Steel spiral around two rubber-and-cloth-covered conductors, and almost never a bonding strip. As mentioned elsewhere in this thread, the insulation crumbles within the box, but the portions in the armor are usually pristine.

Plenty of houses were wired with it around here (Richmond, VA), as there are a lot of Civil War-era houses that have been updated from fireplaces through gas, K&T (on a single 30a, 120v service with both conductors fused), BX (aka AC), that silver-and-tar NM (both with and without ground, even in the same house), thick plastic NM in various colors (black, blue, pink, etc), and modern NM w/G.

It all depends on when the house was built. I've worked on plenty of houses with a mix of several of these wiring methods, including today. I have one rule-of-thumb I try to stick to: never add a load to an existing antique (pre-NM) circuit, especially a receptacle.

If I ran into it, I'd spin on a bond bushing. Wouldn't that suit to originate an EGC tail in the box?
I'd apply a mix of testing and, if permitting/inspecting, consulting with the AHJ on that one. In my opinion, a valid test would have to involve a load-current and voltage-drop test, which could/would/should expose a weakness in the grounding pathway.
 
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jeff43222 said:
Looks cool, but 6.1" isn't going to come close to what I will need to house all those wires. Like most of the pancakes I deal with, there are four KOs, each with two cloth-covered wires coming through them. Realistically, I'd need an octagonal box 2 1/8" deep just to be able to fit all of them in.


This is what I have done in this situation.
I 've used a 12" medallion, 4" pancake and a 4" JB w/cover.
Cut a 11" diameter hole in the ceiling on center with the existing fixture (or support beam).
Splice all of the conductors in a 4 x 2 1/8 octogan and leave a NM pigtail for the light hanging out (about 12" long).
Push the splice box back into the ceiling space.
Install the pancake and pull the pigtail in.
Install the medallion and fixture bracket using the same screws (with fender washers), run the screws thru the bracket, washers, medallion and into the pancake. Don't glue the medallion to the ceiling.
The edges of the fender washers will hold the medallion against the ceiling.
Install the fixture.
I 've done this before. The JB is accessible simply by removing the fixture, bracket (and medallion by default) and IMO meets the intent of 314.29. Not much different than an re-model can.
The medallion that mdshunk referenced looks like a better solution than using a seperate pancake and medallion. You could still use the JB in the ceiling with it too. Simply removing the fixture and medallion would expose the JB.
hope this helps
steve
 
mdshunk said:
...a couple of #14 K&T's or a #14 ungrounded romex. Add a couple of federal bushings for K&T or a the supplied flush NM connector for an old romex, and you're in business.

Marc, Do you have a web site or supply source for the K&T/NM connector-bushing? Thanks
 
jeff43222 said:
Instead of the usual pancake box crammed with cloth-covered wiring, what was there instead was something that looked like a pancake box, but it had no sides.
I have yet to see one, as you describe. I have worked on numerous pancake versions. Usually, in our area, the pancakes are on the end of flex or rigid with cloth covered rubber insulation, two conductor inside a wax impregnated cloth sleeve. The sleeve allowed smooth pull ins of two conductors at a time.

The original practice, at the time of installation, expected that the luminaire had a large volume canopy. As long as a replacement luminaire has a large volume canopy, grandfathering occurs.

If the new fixture has little or no volume in the canopy, and the HO "has to have" the fixture, then the HO "has to have" the box in the ceiling changed out to one with the appropriate volume, IMO.

Paddlefans require a much more difficult install in this situation, especially if the original location has more than one raceway, and / or, the ceiling joist runs right down the center of the location.

Allenwayne made a great suggestion in another thread (the one involving a tin ceiling and short K&T conductors) on a related note: Use a medallion to cover a rough edged excavation.

The medallion will add 1?" or more in depth. One could work in a 4" square or even an 11B with plaster ring for a vanilla luminaire.

I just hope that the raceways / cables at the paddlefan locations are few enough to permit the install of the 8B (4" octagon) fan supports.
 
The original practice, at the time of installation, expected that the luminaire had a large volume canopy. As long as a replacement luminaire has a large volume canopy, grandfathering occurs.


Most new lighting fixture packaging or instructions contain some sort of note requiring 75 or 90 degree C conductors. The large volume canopy and grandfathering might get you past the box requirements but won't help you if the fixture requires 75 or 90 degree C conductors.
 
infinity said:
Most new lighting fixture packaging or instructions contain some sort of note requiring 75 or 90 degree C conductors.
That's a good point to also keep in mind. Thanks for including it, Trevor.

The aesthetic choices of luminaires left to the homeowner after all the modern restrictions are explained, generally guides the HO to accepting the box rebuild or paring down the number or lighting outlets worked on.
 
al hildenbrand said:
That's a good point to also keep in mind. Thanks for including it, Trevor.

The aesthetic choices of luminaires left to the homeowner after all the modern restrictions are explained, generally guides the HO to accepting the box rebuild or paring down the number or lighting outlets worked on.


We deal with this all of the time. A HO is at Big Orange and decides to buy a few cheap fixtures to spruce the place up. We get there and the big bold print on the outside of the box says something to the affect of "This fixture requires 90 degree C conductors. Most homes built before 1985 have conductors rated at 60 degrees C. Please consult with a qualified electrician before installing this fixture".
 
Here are a few pictures of the "box" I yanked out yesterday:
View attachment 203
View attachment 204
Note the sleek, aerodynamic profile. Very compact, with a total capacity of approximately 0 cubic inches. This thing was screwed into a loose 2x4 sitting on the lath behind the plaster. There were four pieces of old MC connected to it, with two cloth-covered wires in each one.

Fortunately, there's enough space up there for me to install a fan spreader box between the joists, and the box will be big enough to house all the wires. Looks like I won't need a medallion after all, but thanks for the good suggestions.
 
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Wow!

Will ya look at that!

Why, I can think of a couple places that I need that "box" for. . .;)

Seriously, though. It looks like the bottom of an 8B with cover holes added. Just like you described. That's the first one I've seen.

Thanks for the followup pics.
 
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