Convert RMC Flat Pan to Paddlefan Support

[al hildenbrand]

I have been contacted after the new drywall over plaster and lathe was installed.

The existing flat pan was installed with black paint RMC in the first decade of the 1900s.

The client wants to install a paddlefan, now. How would you convert this?

There are two locations. This one, above, and the another with two conduits.

 

[jumper]

Any overhead access by chance?

 

[muskrat]

That "RMC painted black"(you devil) may be old gas piping stubbed up thru/ supported by 2X4 in attic. There is a manufact. that makes a fan rated pancake box. Talk to AHJ but #10-32 screws run down thru top of box and nutted on bottom of fixture strap may satisfy intent of code. Looks like old TW wiring too. Good luck.

 

[al hildenbrand]

Any overhead access by chance?

Nope. Second floor above.

 

[RICK NAPIER]

Magnify the picture and it looks like an old fixture stud mounted on the back of the box usually with 1" screws to a 1" by 6" or 1" by 4" nailed in across the joists. This wood could be very solid or dryed out and prone to splitting. I would not count on it to support a fan.

 

[K8MHZ]

Hard to tell, but that looks like cloth insulation, to me. I have never seen wire with cloth insulation pulled into a pipe. It looks like old K&T.

Also, I have never heard of an 'RMC Flat Pan' and the pic looks like a plain old pancake box that is usually fed with BX or old nasty Romex.

I would also like to take this opportunity to warn you that 'pan box' usually means 'Pandora's Box'.

 

[K8MHZ]

That "RMC painted black"(you devil) may be old gas piping stubbed up thru/ supported by 2X4 in attic. There is a manufact. that makes a fan rated pancake box. Talk to AHJ but #10-32 screws run down thru top of box and nutted on bottom of fixture strap may satisfy intent of code. Looks like old TW wiring too. Good luck.

The intent of the code is to only use boxes designed specifically to hold up ceiling fans to be used as support. In addition, another intent of the code is to make sure the max weight is listed. Nothing you can do to the box in question will make it compliant to hang a fan from. If the box is to stay, the fan has to be supported from something else.

 

[al hildenbrand]

Hard to tell, but that looks like cloth insulation, to me.

These conductors are generally R, RW, RH, RHW or the like. If they are discreet, the cloth has a wax pre-installed for pulling. Sometimes the wire was provided from the manufacturer in groupings of two or three conductors inside a thin cotton "sock", running the length of the spool or coil of conductors, that was lubed with the pull-in wax.

I have never heard of an 'RMC Flat Pan' and the pic looks like a plain old pancake box that is usually fed with BX or old nasty Romex.

Remember, this is original to roughly 1908. The core, as-built wiring method for this single family two story wood framed dwelling was black painted Rigid Metallic Conduit.

And, Yes, you are correct, the flat pan is generic.

The installation method was the same as that for gas lighting, still readily installed at that time. The carpenters framed the floors, but did not install the subfloor until the pipe fitters were done installing, whatever, the gas light or the electric light (when the electric wiring method was RMC).

The pipefitter would notch the top side of the floor joists to lay the run of RMC in and would bend a 90? stub down to the flat pan. There was no cubic inch requirement, then, for the box, in the way we have now. The early 1900s luminaire canopy was expected to house the splices.

In it's day, this was a Cadillac wiring method in dwellings.

 

[iwire]

I would leave the boxes in place and support the fan independently of the box.

One possibility would be to remove the KO that is left and stick a 'Sammy' http://www.itwbuildex.com/sas_wood.shtml on the end of 1/4" threaded rod, run it up through the KO and into the wood above.

Once into the wood enough cut the threaded rod, install a fender washer followed by a nut to tighten up against the box to cover the KO hole and use the remaining threaded rod sticking down to support the fans bracket.

 

[Ravenvalor]

Lowes sells a great little ceiling fan pancake box that is perfect for this application. They're only about $3 so I use them all the time.
You might want to take that old wiring and put it into another junction box in the attic and send a new spliced cable into the new box. Either way I don't think you can connect the old wiring directly to your new fan because of its temperature rating.

 

[marti smith]

That is good if you have a stud above the box, but if not (and often these pancake boxes went right to the lathe) then Arlington makes a steel fan box with adjustable mounting brackets that we have used with much success, between the studs in the ceiling. There is no need to get above the ceiling although the lathe will need to be cut out for inserting the box. Another pretty cool option IMO.

 

[Dennis Alwon]

I would get a pancake fan box and use an old work fan support bar like pictured below. Turn the bracket upside down and use the pancake box instead of the one given.

 

[K8MHZ]

I would get a pancake fan box and use an old work fan support bar like pictured below. Turn the bracket upside down and use the pancake box instead of the one given.

Those work great just like they come. No need for a pancake box or access to the top side. They won't work where the old box is mounted on the bottom of a stud or a rafter.

 

[jumper]

If all else fails, and the customer is okay with it, cut a decent workspace around the old boxes, do what you gotta do and use a medallion to cover hole.

 

[Dennis Alwon]

Those work great just like they come. No need for a pancake box or access to the top side. They won't work where the old box is mounted on the bottom of a stud or a rafter.

Mark --- the box that is in the hole is a shallow pancake box with black pipe in the KO. How do you propose to move the pipe up to accommodate a deeper box.

 

[K8MHZ]

Mark --- the box that is in the hole is a shallow pancake box with black pipe in the KO. How do you propose to move the pipe up to accommodate a deeper box.

Good point. I didn't think of that...

 

[iwire]

I would get a pancake fan box and use an old work fan support bar like pictured below. Turn the bracket upside down and use the pancake box instead of the one given.

Those are cool, I have two similar to that in my own house.

But I think getting it into the hole with one and two 1/2" conduits is going to be tough.

 

[chris kennedy]

And how would you get a conduit into the top of that box?

 

[guschash]

If you ever tried to take one of these out of the ceiling, good luck. They are there to stay. You probably could hang from that box. The new ceiling bonnet will have room for the wires from fan. Use wood screw with new bracket you will be ok. Been in alot of old house and the wood is solid unless it rotted.

 

[al hildenbrand]

I would get a pancake fan box and use an old work fan support bar like pictured below. Turn the bracket upside down and use the pancake box instead of the one given.

And how would you get a conduit into the top of that box?

Chris, I think that's an interesting question.

Now, the 1?" deep octagon would stand proud of the new drywall surface in the OP photo, as the old plaster and lathe are ?" and the drywall is ?", so the box would be ?" proud.

So, I like the idea of using the paddlefan rated flat pan with the expandable brace.

Seems to me I have to drill the ?" KO. That is, if the alignment (especially for the two-?" conduit location) works with the run of the expandable brace.