Exterior Electrical Service Panel Mounting

[MountainDon]

Over the past numerous decades I've done a lot of electrical work, some even passed inspections, but one thing I've not done is the installation of a load center on an exterior wall.  I don't have space inside the cabin for a panel and therefore will need to use an exterior type. For the curious it'll be a Square D, QO series; they have probably got the best breakers in the business, quickest reaction times.

So here's the crux of my question. The exterior walls will not be finished beyond the tar paper shack stage until spring next year more than likely. I want to get the place wired soon so I can work on the interior walls.

So, do I nail/screw a piece of ext 3/4" plywood over the building felt and attach the panel to that? If so, should that plywood be spaced away from the building paper?

Then later when the siding goes on should I just trim around the plywood with the lap siding or shingles up to and around the plywood?

The inspectors have no say in this, but I want/need this to be safe and installed in a manner to prevent any water/weather problems.

Thanks.

[glenn kangiser]

I don't see any reason you couldn't do that with proper flashing, etc.  Are you coming in underground, Don?

Seems it would have to be tight as the Romex will have to pass through the wall also.

[MountainDon]

My thoughts were to run the power IN to the panel from the inverter using one of the bottom knockouts and conduit. The lines OUT through the hub on the top of the panel, with one large conduit entering the attic through the gable end wall. That way there's no perforations right behind the panel.

The battery enclosure would be external on the same end wall, like a small insulated shed roofed 6 x 3 addition. The inverter at one end of the battery enclosure, completely separated from the battery space with ample venting for cooling, but sheltered from rains, etc.   

[PEG688]

Why don't you recess  it into the stud bay , pull your wire's inside like normal ,(in and out the top and bottom plates.

So only the access door shows on the exterior. You could build a little eye brow ( a straight one ) roof -let over the access pnl.   

[MountainDon]

Thanks PEG.

That never occurred to me. Obviously!      

I guess that's why I posted the query.   

[PEG688]

I did a quick look on Sqr. D site and couldn't find a exterior panel but I know they have them . The door is more a hatch as they tip up to open.

If you look around , maybe at your local Borg, they may have exterior type panels.   

[MountainDon]

as this...

[n74tg]

While you will have an "elegant" solution to the problem by recessing the panel into the stud bay, you won't have any insulation there (depending on wall thickness), hence a cold spot in winter. 

I mounted my exterior panel on 1.5" standoff's (3/4" PVC) pipe just so I could get in behind the panel (easier) when I install the Hardie siding later.  I did this as part of the initial service installation and the utility company had no problems with the idea.     

[MountainDon]

I like that idea too. (The wall is 2x6 framed). 

Did you use the Hardie Plank lap siding? That's what we're leaning towards. Maybe the Hardi Shingles on the upper gable ends.   

[JRR]

Will there be any roofed-porch area or utility room?

[Okie_Bob]

I mounted a main breaker panel on the outside wall and my panel with all the breakers flush with the inside wall so I could run all my romex top or bottom of the inside panel. There is a piece of PVC between the outside panel and the inside one. I used Hardi Plank siding too.
That was in the garage I built and it is working just fine, no rain or wind leaks at all. Being a garage I used 2 X 4 stud walls and no insulation in the walls, only under the metal roof and in all walls in the apartment.
The meter base sits next to the outdoor panel. I wired underground from the road to the meter base. Had to have a licensed electrician to run that wire and have it inspected by the power company. The only inspection of any kind on my entire house. When I then built the house, I ran from the garage outside breaker panel, down and underground to the house outside wall and up into another main breaker panel which has breakers that go out to a boat house, outside lighting system and something else, I forget. Then again through PVC stub into the breaker panel inside a utility room. Everything inside the house runs through that panel. Again, used Hardi Plank siding but did blow in Icyene insulation to seal the panels.
Works great, no problems.
OKie Bob

[TheWire]

Don,

You might consider trying to go with an indoor panel and cleverly hiding it or placing it in a closet.  I have a sub-panel in a finished area of my log home covered with a picture.  While the outside panel is "weather proof", I have seen moisture and bugs get into them. That, plus you need to side around it, have a box in open view on the outside of your cabin and have to go outside to access it.

Is your power from an inverter?  With an inverter, you may want easy breaker access to shed parasitic loads from TVs, microwaves, radios, etc.

I guess I'm one for keeping as much as possible dry and accessible on the inside.  Good choice on the Square D QO breakers.  They are one of best.  They are also rated for up to 48 Vdc (On the 10–70 A breakers).  I'm using 3 small 6 place QO breaker panels in my cabin.  1 for inverter power, one for 12VDC and 1 for power from the genset.  I'm placing them behind a bedroom door.

Jerry

[MountainDon]

Will there be any roofed-porch area or utility room?

No utility room.  Small porch at front entry. K has already nixed the idea of putting a panel on the front entry end.

What there will be is a battery enclosure on the end where I visualize placing the load center panel. It will be built like a small lean to, small shed roofed structure on the cabin end. It will be large enough to hold, and access for maintenance, up to 12 L16 size batteries although I still may just use GC2's. This will have minimum 2x6 wall framing with insulation to moderate the battery temperatures. On the left end there will be a vented compartment for the Outback MX60A charge controller. This will be isolated from the battery compartment. The battery compartment of course will have its own venting to get rid of the gases.

[MountainDon]

.... covered with a picture.  .....

Is your power from an inverter?  With an inverter, you may want easy breaker access to shed parasitic loads from TVs, microwaves, radios, etc..

That's something to think about (behind a picture)

Power will be from an inverter. The plan includes several switched outlets;some for lamps plus for the Microwave, TV and an extra or two. Maybe that way we'll avoid having too many of those power strips scattered about.


There will also be some DC power, and I've not decided on what it shall comprise. (First of all the batteries will be wired as a 24 VDC system.) I want to have an RCH DC ceiling fan. It can run on 12 to 24 VDC. It can move more air on 24 VDC. With an electronic speed controller it's the ultimate off grid fan especially when fitted with the scientifically designed "cyclone" blades. So I'd like 24 VDC.

I also want two fluorescent lights that run on DC, in case the inverter craps out; I love redundancy. Thinlites are available in 12 or 24 VDC.

Then there's the inside water pump to pressurize the system from a ready-use tank, like an RV. The Flojets and Shurflo's are available in 12 or 24 VDC or 11 VAC. The 12 VDC are available readily at any RV store. The others are usually special order. I'd like to have either one of the DC

As well I'd like to have some 12 VDC as I can use that for charging cell phones, etc with less power cost than doing it through the inverter.   

So I may end up with both a 12 VDC and a 24 VDC system... 12 VDC off a center tap on the batteries or use an electronic converter     Decisions...

[glenn kangiser]

12 volt center tap will tend to draw down that half of the batteries -- maybe check balance every so often - add a center tap panel to charge it if needed? hmm

[MountainDon]

Yep. Something to be mindful of.

Mainly the 12 VDC would be for the pressure pump that only runs when a tap is opened. Nit all that often.

[glenn kangiser]

Also - if running two of the same thing at 12 v you can series them for 24v.  I run two 12v car relays in series to make a 24v coil to control my pump from a 120v timer which switches a 240v relay.  Cool, eh? hmm

[MountainDon]

More news to add to this ...

I made an inquiry this AM with Outback Power Products, Their literature doesn't state the lowest operating temp for their inverters. Xantrex states their units can operate down to 32 degrees F, Magnum Energy goes down to -4 degrees F. Outback has an operating range that starts at -60 degrees F!!  Outback just sold another unit. 

That will allow me to place the inverter right next to the batteries, in it's own vented compartment safe from the battery gases. I was certain I'd have to have it inside, but not with the Outback. Looking at the VFX3524; 3500 watts, 24 VDC feed.


Also, re the 12 VDC tap... that's another thing I like about using a 24 VDC to 12 VDC converter. I don't like the $$$ though.

[gandalfthegrey]

I know a family up in Tok Alaska that is using the Outback equipment at -70* F.  They haven't had any problems yet.

[MountainDon]

I've always thought highly of the Outback brand. There seems to be no end of reasons to go with them.

[NM_Shooter]

Is the smallest Outback inverter their 2kVA model?

-f-

[MountainDon]

The FX2012 is the lowest output inverter Outback offers. It's a sealed, non-vented unit. In the vented series the VFX2812 is the lowest output. Note these two operate off 12 volts. They are inverter/chargers like most. The Outback sealed units have worked extremely well in places like the deserts of Iraq. The vented series is basically the same as the non-vented model with the venting added. This increases the cooling ability and allows a higher max output. Not too much difference in price between the two.

The non-vented are NOT waterproof, but they are dust proof.

Another brand I considered is Exeltech. They have inverters with no charger, and they have an operating range that goes down to -15 degrees F, IIRC. Pure Sine wave too. The maximum output in their XP series is 1100 watts. Less than $900. They have another series that is stackable for increasing outputs, but that route costs close to Outbacks products.

If I figured I could do with only 1100 watts I'd go for the Exeltech XP1100 as I have a perfectly good 55 amp 12 VDC charger. If my cabin was for just me roughing it I could likely make it work.

[MountainDon]

One more FYI on inverters. Most usually get derated at higher elevations. I know Outback rates theirs up to 15000 feet and Exeltech rates theirs to 10000 feet. Thinner air = reduced cooling available.