Question about running wires in a house

[GoodJBoy]

Hi Everyone,

I have an off grid system (solar panels, charge controller and batteries) that runs lights and soon, a Sundanzer freezer. For the freezer, I ran 4 gauge wire. My home is on the grid but this off grid solar is kept separate from the existing electrical. I do not invert the solar power. I keep it DC. I do not run DC wires into 120v AC connecting boxes as I fear that someone might hook up the 120V AC to my battery bank.

That said, I have Romex wires from the AC run around my attic. As you know, the Romex wires are regular wires with extra insulation around them. You can run Romex and tack it down and snake it through holes without having to use conduit. Can I run the 4 gauge DC wires (which are simply regular thick wires with red or black insulation - no extra insulation) just like Romex is run... meaning... do I need to put them in conduit or can I just tack them up as if they are Romex? I am talking about from a code perspective. I know codes change from location to location and my codes my be different than your codes but I am just looking for some feedback and guidance.

Thanks! This forum is golden!

[inetdog]

Hi Everyone,

I have an off grid system (solar panels, charge controller and batteries) that runs lights and soon, a Sundanzer freezer. For the freezer, I ran 4 gauge wire. My home is on the grid but this off grid solar is kept separate from the existing electrical. I do not invert the solar power. I keep it DC. I do not run DC wires into 120v AC connecting boxes as I fear that someone might hook up the 120V AC to my battery bank.

That said, I have Romex wires from the AC run around my attic. As you know, the Romex wires are regular wires with extra insulation around them. You can run Romex and tack it down and snake it through holes without having to use conduit. Can I run the 4 gauge DC wires (which are simply regular thick wires with red or black insulation - no extra insulation) just like Romex is run... meaning... do I need to put them in conduit or can I just tack them up as if they are Romex? I am talking about from a code perspective. I know codes change from location to location and my codes my be different than your codes but I am just looking for some feedback and guidance.

Thanks! This forum is golden!

Almost everywhere in the US follows the National Electrical Code (NEC) but with a lot of variation on which year version they use, ranging from 2008 through 2014.
But in all of them it is not allowed to run individual wires (without the extra covering of NM (Non Metallic sheathed cable, the generic for the brand name Romex(TM))) either concealed in walls or in the open unless you put them in conduit of some sort. That can be Schedule 40 PVC (gray plastic electrical conduit) or metal from the thin EMT that we usually call conduit on up to "pipe".

The insulation on the single wires does not adequately protect them from either mechanical damage or UV and especially is not designed to be stapled to walls.

PV wire, on the other hand, has very thick insulation and can be run without conduit in some cases. But it costs too much to be used for general 12V wiring such as yours.

[Mike90250]

What was the source of your 4ga wire - an electrical shop selling 600V insulated wire, or a auto stereo shop selling wire with vinyl insulation that will fail in a hot wall/attic ?

but as stated, it needs to be protected in the walls.

[Sunking]

You have to use either Non Metallic sheathing or run it in pipe. FWIW Romex is a trademark name of Rome Wire and Cable now owned by Southwire. There are many manufactures of NM cable. Largest gauge available in NM is #4 AWG. Another cable type is MC.

[Shockah]

What was the source of your 4ga wire - an electrical shop selling 600V insulated wire, or a auto stereo shop selling wire with vinyl insulation that will fail in a hot wall/attic ?

but as stated, it needs to be protected in the walls.

Weird,,, and they say don't use household wire in automobiles because it cannot endure the high temps, oil & road blast...

IMHO, the temps of an engine compartment is much more brutal than an attic.

[s2man]

it is not allowed to run individual wires ... either concealed in walls or in the open unless you put them in conduit of some sort.

How do folks get around that requirement at the battery bank?

FWIW, I have surface-mounted conductors to everything directly connected to the bank. For the runs through the house for 12V lights, fans, etc., I used conductors rated for in-wall installation.

[inetdog]

How do folks get around that requirement at the battery bank?

FWIW, I have surface-mounted conductors to everything directly connected to the bank. For the runs through the house for 12V lights, fans, etc., I used conductors rated for in-wall installation.

The battery bank is part of your power source. Up to the point where it connects (after fuses or circuit breakers) to the building wiring is the point where you have to worry about using "building wire" of any sort and the restrictions that accompany it.

Also, some types of wire are listed as "portable" or "flexible" cord and have insulation which is abrasion resistant, etc. suitable for open runs. As long as it is protected from mechanical damage.

As for the automotive versus house wire, the automotive wire is generally gas and oil resistant where that is an option for building wire.
And the voltage rating of the automotive wire insulation will not be the 150V or up to 600V usually required for building wiring.
The temperatures in the engine compartment are potentially high, but so are the temperatures in conduit in the sun on the roof. The rest of the car, not so hot.

[Shockah]

As for the automotive versus house wire, the automotive wire is generally gas and oil resistant where that is an option for building wire.
And the voltage rating of the automotive wire insulation will not be the 150V or up to 600V usually required for building wiring.
The temperatures in the engine compartment are potentially high, but so are the temperatures in conduit in the sun on the roof. The rest of the car, not so hot.

^^^ Noted. Thanks.

For lighting runs, (always less than 3 amps),
I use 14ga or 16ga Landscape Wire.
150v / UV resistant.

Thoughts?

porch run.jpg

[inetdog]

^^^ Noted. Thanks.

For lighting runs, (always less than 3 amps),
I use 14ga or 16ga Landscape Wire.
150v / UV resistant.

Thoughts?

My first thought it that as long as you have current limiting to a safe amperage for the Landscape Wire you should be OK. The other type of wire listing (Class 2 or Class 3 Limited Power) is not going to be NEC acceptable unless you use a listed limited power source for the circuit.
Using landscape wire in concealed locations (inside walls) is not within the Landscape Wire listing uses, although an alternate listing of CL2 or CL3 for the same wire would allow that, but only if you use a listed power source.
It gets interesting.

[Shockah]

Using landscape wire in concealed locations (inside walls) is not within the Landscape Wire listing uses,

Ok... but how about along an exterior rafter or under an eve?
Stapled-on LW ok?

It gets interesting.

Very.
That's why I'd rather only build post-mounted assemblies...
But then you got the structural & footing AHJs looking over your shoulder.

[inetdog]

Ok... but how about along an exterior rafter or under an eve?
Stapled-on LW ok?

AFAIK fine, but YMMV. It is used that way for landscape lighting all the time. The power source is typically a 300W max transformer though FWIW.

[Shockah]

AFAIK fine, but YMMV. It is used that way for landscape lighting all the time. The power source is typically a 300W max transformer though FWIW.

Cool... Thanks,,, that's comforting.
I'll note the 300W max.

On all LW uses so far,
Max power= 36W. (3amp fuse)
Max load= 10W.

What's also comforting is it doesn't take much-of-a-"short" from either end to pop a 3amp fuse.

[inetdog]

In many ways you have it easier than people who try to wire solar or other low voltage lighting indoors. Think under cabinet, accent, etc, rather than just 120v incandescent can replacement. They need to meet the full force of NEC including wiring in concealed spaces, etc. As a result they are often forced to run NM, conduit, or BX for low voltage low current DC.