Flush Mount Breaker Panel - Future Wiring

[Spudland_Dave]

I know theres some debate on this, but I Havent seen a solid yes/no in the case of my situation....

Getting ready to mount my new panel in the new garage, in case it matters, its a 24 space Homeline. Going to flush mount it in the stud cavity, 2" foam board behind it for insulation... for the next few months I should have no problem doing wiring, but thinking ahead, I will be insulating and finishing the interior at some point. What I'd like to do is install 2 or 3 2.5" conduits from the box up through the top plate so even when I insulate and finish the garage I can easily add/remove/change any wiring without having to tear apart the wall. I also think even without finishing it right away, it would be easier/neater of an install with the conduits.

For the most part I would be running 12-2 and 14-2 Romex through it, with a couple of 6-2 and 8-2 wires for the big stuff like welder & compressor.

Proceed or Change course?

 

[Charles (in GA)]

Fully insulate the wall, surface mount it, and build a chase the same dimensions as the panel to run up the wall to the ceiling/attic. Put a removable door or hinged door on the chase for access. You get full wall insulation (which you need in Maine) and a nice looking, accessible chase for the wires.

You could have code issues running conduits with multiple wires in them. (derating, conduit fill, etc.)

Charles

 

[Stuart in MN]

Short sections of conduit used as chases to protect the cables are permitted and the regular conduit fill rules don't apply, but the question is how long the section of conduit can be. I assume it's no more than a couple feet, but hopefully one of the other guys here who have more experience in residential wiring can chime in. There's a little info here about it: http://www.selfhelpandmore.com/home...lculations/calculations-conduit-fill-2002.php

 

[Spudland_Dave]

You could have code issues running conduits with multiple wires in them. (derating, conduit fill, etc.)

Charles

No code to worry about where I live. Quite honestly the only code I needed to abide by was 15' from a Property line, 25' from a road.... The only inspection ever done is if the measurements are close...for example if I applied for a building permit and I was 18' from the property line...they'd come double check to be sure prior to issuing.

BUT That being said, I still care about safety....and equally important to me is asthetics. IF Were to surface mount it, I think i'd rather look at nice neat conduit surface mounted on the wall instead of a chase....I know I know..I'm not easy to please. I just have this vision for my own version of a Garage-Mahal...on the car side of the shop (where this box will be) I'm picturing basically a living room which happens to have a concrete floor and really big doors which allow cars in I'm even taking apart the panel cover and painting it white instead of gray.

Short sections of conduit used as chases to protect the cables are permitted and the regular conduit fill rules don't apply, but the question is how long the section of conduit can be.

Yeah, I've read that and have been plenty confused by it as well....i've got 10' walls, so if I mount the box at a nice height of +/- 30" off the ground, Probably looking at a conduit length of 5' or so....

 

[royalton10]

Yeah, I've read that and have been plenty confused by it as well....i've got 10' walls, so if I mount the box at a nice height of +/- 30" off the ground, Probably looking at a conduit length of 5' or so....[/QUOTE]

I would think 30" would be a little low.

 

[Charles (in GA)]

The problem with using large conduits with bunches of romex in them, running out of panel boards, is that the other end of the conduit is open, the wires are not clamped either at the entry to the panel board, or at the top of the conduit where it passes thru the header and enters the attic. This leaves a pathway for fire, and violates rules for clamping the cables where they enter the panel board, which are designed to both clamp/support the cable, and also to seal the opening for fire protection.

When you use a chase, the panel board still has the wires clamped in the romex clamps at the top and bottom of the board, the chase just provides a method of hiding the wire, and protecting it. You also have the opportunity to use the romex clamps that individually support multiple romex runs as the cable makes its way up the wall.

Ideally, the opening at the top of the chase, where the wires enter the attic, should be sealed after the cables are run, with a proper fire resistant sealer/foam. If you need to run more cables in the future, you just have to tear out the sealer/foam and re seal after you are done.

Whether you have codes applying to you or not, it is not a bad idea to stay close to compliance with those parts of the codes that provide for fire safety.

Charles

 

[Stuart in MN]

The problem with using large conduits with bunches of romex in them, running out of panel boards, is that the other end of the conduit is open, the wires are not clamped either at the entry to the panel board, or at the top of the conduit where it passes thru the header and enters the attic. This leaves a pathway for fire, and violates rules for clamping the cables where they enter the panel board, which are designed to both clamp/support the cable, and also to seal the opening for fire protection.

Good point - the romex does need to be clamped and I'm not sure how that would be done with a conduit connected right to the panel.

I have seen a chase like Charles described earlier used before and it works well. I wonder if you could recess it into the wall, by using foam insulation behind it (to make up for the loss of insulation space) and with a metal door or access plate on the front (to provide protection for the romex.)

 

[Spudland_Dave]

I would think 30" would be a little low.

Could very well be, I was just picking a number out of thin air while sitting behind my keyboard.

I have seen a chase like Charles described earlier used before and it works well. I wonder if you could recess it into the wall, by using foam insulation behind it (to make up for the loss of insulation space) and with a metal door or access plate on the front (to provide protection for the romex.)

All very good points...so, what I COULD do...thinkin out loud....is just use some strapping inside those 2 studs as a nailer above the box and use 2x4 Fiberglass Batt insulation on that section. I'm guessing that a 2" x 14.5" "raceway" is more then enough to run the wires required for a 24 space panel box. Technically this works...But asthetically....I dunno...

 

[Falcon67]

I flush mounted my panel with the main a little below eye height. I drilled several 1" holes in the top plate above it. I placed a 2x8 between the studs and flat up against the back side of the siding about 8" above the panel top. When I ran the circuits, the Romex comes in through the plate, down through a clamp in the top of the box for that run and then it's stapled to the 2x8. I picked 2x8 because I had some scrap and I could stagger the Romex staples close together. When I was all done, I laid a piece of fiberglass insulation in the cavity and cut an OSB panel to seal it up. 4 screws and it's off for running more wires. There is also a 20x20 access panel in the ceiling right over the box.

Mine is a 20 circuit box, BTW.

 

[rockwithjason]

run a few 1" conduits up the wall to a jbox mounted in the attic. no clamps to worry about, no big pipes to fool with. much easier set up.

 

[johno]

run a few 1" conduits up the wall to a jbox mounted in the attic. no clamps to worry about, no big pipes to fool with. much easier set up.

^^^ What he said.^^^
BUT

As I recall Romex is not to be run in conduit, and a Jbox is not be used as a raceway. So run romex to Jbox terminate there and run th down to panel.
Use a good size Jbox, makes life easier.

 

[Stuart in MN]

^^^ What he said.^^^
BUT

As I recall Romex is not to be run in conduit, and a Jbox is not be used as a raceway. So run romex to Jbox terminate there and run th down to panel.
Use a good size Jbox, makes life easier.

It's a commonly held belief, but there's no problem with running Romex in a conduit as long as the conduit is sized properly.

 

[pattenp]

It's common to have conductors that pass through J boxes. That's why the fill calculation is different for conductors terminated in the box vs passing through the box.

^^^ What he said.^^^
BUT

As I recall Romex is not to be run in conduit, and a Jbox is not be used as a raceway. So run romex to Jbox terminate there and run th down to panel.
Use a good size Jbox, makes life easier.

 

[johno]

I guess we have different rules?

 

[pattenp]

I've noticed that Canada code seems to be stricter on some things than the US code.

 

[jrusso]

^^^ What he said.^^^
BUT

As I recall Romex is not to be run in conduit, and a Jbox is not be used as a raceway. So run romex to Jbox terminate there and run th down to panel.
Use a good size Jbox, makes life easier.

I would have to agree that Romex is not meant to be run in conduit as it will not dissipate heat the way it would run free air as it was intended for and is not listed for this use. The insulation on the conductors contained in the jacket them selves are not marked with any identification stating their temp rating, so technically it would be necessary to splice them at the junction box to another listed conductor such as THHN. At that point you could properly de-rate the ampacity of conductors if required by conduit fill.

 

[frankush]

run a few 1" conduits up the wall to a jbox mounted in the attic. no clamps to worry about, no big pipes to fool with. much easier set up.

This is the way I'd do it. You could use THHN from the J box to the panel. Splice your romex to it and your done. Do I like splices? No. I'm from Chicago. Everything would be piped and even with the J box in place, I'd pull through it to the panel.

 

[Charles (in GA)]

I would have to agree that Romex is not meant to be run in conduit as it will not dissipate heat the way it would run free air as it was intended for and is not listed for this use. The insulation on the conductors contained in the jacket them selves are not marked with any identification stating their temp rating, so technically it would be necessary to splice them at the junction box to another listed conductor such as THHN. At that point you could properly de-rate the ampacity of conductors if required by conduit fill.

There is nothing in the code that forbids the running of Romex in conduit, and in fact, Chapter 9 even discusses the methods of calculating fill when cables and cords are run, and even tells you that elliptical cable (such as 14/2 or 12/2 Romex is to have its area determined by measuring the major diameter of the ellipse and assuming it is a circle. It also says that a jacketed multi-conductor cable or cord is to be considered a single conductor for the purposes of fill calculations.

Charles

 

[e-tek]

I've noticed that Canada code seems to be stricter on some things than the US code.

It's the same for most everything - and the main reasons our Banks are stable!


As for surface mounting boxes - I thought it was to keep the box/wires/connectors on the warm/dry side of the wall.

 

[Highbeam]

I flush mounted my panel with the main a little below eye height. I drilled several 1" holes in the top plate above it. When I was all done, I laid a piece of fiberglass insulation in the cavity and cut an OSB panel to seal it up. 4 screws and it's off for running more wires.

This is what you do it is just like a house. I make a special sheet of OSB or sheetrock for this stud cavity to allow easy access for future work. I see no drawbacks. You still have insulation.

You do the same thing behind showers. Plumbing in the wall but provide an access panel. Beats the heck out of surface mounting everything for the few times you will actually need access.

 

[Spudland_Dave]

There is nothing in the code that forbids the running of Romex in conduit, and in fact, Chapter 9 even discusses the methods of calculating fill when cables and cords are run, and even tells you that elliptical cable (such as 14/2 or 12/2 Romex is to have its area determined by measuring the major diameter of the ellipse and assuming it is a circle. It also says that a jacketed multi-conductor cable or cord is to be considered a single conductor for the purposes of fill calculations.

Charles

I'm gettin a little smarter with the whole electric code thing, and I'll have to say Charles is right. I was talking to a sparky workin a jobsite here about it...he lives not too far from me and saw my shop going up...so we were talking about it and I was asking him random Q's about panel placements (see my other posts) and was talking about putting pull strings in before insulating my ceiling so I can pull a romex under my attic floor down the road. Told me I should just put a conduit then the conversation shifted to the "I thought it was against code" Long story short he gave me 30' of 2" ENT and I put a run directly under my floor in 2 spots.