LEDs, and Wiring for them

[old_guy]

I will soon be installing the electric service panel in our under-construction Tennessee home.  Our power is off-grid solar, so reducing power consumption is high priority. 

The few temporary lights installed now are LEDs that screw into standard 110v sockets.  I know there are other options, but do not know what they are.

Is LED lighting available that runs directly on DC?

Is DC powered LED lighting preferable?

How should the house be wired for non-AC LED lighting circuits?

Can you recommend a site where I can learn about the options?

Time to learn. 

Thanks.

[DaveOrr]

The bulk of my lighting is low voltage recessed lights.
The bulbs used in the fixture are either GU10 or in my case MR16's.
The fixtures have a transformer to drop 110v to 12v. I bypassed the transfrmer to run directly off 12 volts.
I use LED MR16 bulbs in my fixtures.
Still have a lot to do but currently have my first floor running off a little 7ah 12 volt gel battery.



You can also purchase 12volt LED bulbs that fit regular lamps and fixtures.

https://www.amazon.ca/s?k=12+volt+led+bulb&gclid=Cj0KCQjwoqDtBRD-ARIsAL4pviC-BF0vVWxHCgEaTvYM9H_CDyF0cGANQfxy886iNtTw5p8GkF_3VVUaAmmaEALw_wcB&hvadid=230011199716&hvdev=c&hvlocphy=9001629&hvnetw=g&hvpos=1t1&hvqmt=e&hvrand=158553901970645517&hvtargid=aud-748919244907%3Akwd-301442466869&hydadcr=27415_10624891&tag=googcana-20&ref=pd_sl_659t3evjja_e

FYI, when running your wiring it's best to run a different colour for 110AC and low voltage DC.
I have 3 different types as my closet lighting is 5vdc, my main lighting is 12vdc and I also have 110vac outlets and lighting also.
Will have a legend in my electrical room detailing the different cables, also I am putting together a manual on all the systems so the next owner will know how everything is set up.

My solar setup will likely be 24 or 48 volt so I will be using a DC to DC converter for my low voltage lighting.

[MountainDon]

We have a mix of AC and DC. The cabin has AC wiring just like you would have for a normal grid-tied home. That way we can elect to use any AC device that comes along. More or less anything as your choice is dependant on storage capacity as well as the inverter size.

I also installed some DC wiring.  A 10 gauge 24 volt line from the battery bank terminates in a fuse protected 24 VDC to 12 VDC converter under a kitchen base cabinet. The 24 VDC is used to power a DC ceiling fan. The 12 VDC is used to power some LED strip lights under the kitchen cabinets as well as a 12 VDC strip light in the bathroom and a 12 VDC LED light near the dining table.  These lines have their own ATC type fuses in a small block by the converter. Originally I wanted some DC lights to cover us in case the inverter crapped out. That happened when lightning struck a few years ago. In recent years I added a couple of 12 volts to 5 volt USB sockets for use charging assorted devices.  I used romex 12 gauge wiring for most wire runs, with multiple tags denoting the wires that are DC.

I also have a cabin user manual with photos and diagrams that documents all the wiring, AC or DC and voltage as well as other details. That's to help me when I get more forgetful as well as anybody else who may be called on to perform any future work.

I am a tinkerer. I bought strip lights and other devices from Chinese vendors I found on Aliexpress.com. I have a couple of LED lights sold for use in RV's. There are many 12 VDC LED illumination devices available. I also have intended for RV use, pumps and fans that operate on 12 VDC. Most if not all, will not have UL approval. That does not necessarily mean the devices are no good. UL testing costs money.

I soldered, wired, encased assorted devices on my own. I am comfortable with that. They are not UL approved devices. Being surrounded by forest nearly in the middle of nowhere, actual dwelling insurance has been crazily priced here since we started building. So we are self-insured. DIY electrical devices could cause an insurance claim to be voided. Keep that in mind.  Buying from China also means basically no warranty as returning defective goods to there can be cost-prohibitive.

Fuse all the DC lines or use breakers that are rated for DC use.  Fuse or breaker sizes are selected to provide short circuit protection to the wires, not to protect the devices, just to be clear on that.   My DC wiring uses black for + and white for negative wherever I have used romex type (black/white/bare) wires. To make everything make more sense to me I also use white/grey for all the other DC wires and black or red for the +.  I used red heat shrink wrap tubing at the ends of any DC + wires like at switches, etc. That helps remind me it is DC. As well I used white heat shrink on the ends of any wires that were not already white, such as some of the heavy gauge wires that connect to the batteries or devices such as the inverter. I can't say that was necessary but it helps me keep things sorted after all these years.

an example of a Chinese LE strip light I have located in the battery closet.  This one is available with or without with a 220 VAC to 12 VDC adapter plug. China is 220 VAC so many chinese imports are 220, not 110-120.  That is just informational not an endorsement necessarily.

[Dave Sparks]

If you have home insurance and care about it being valid in a claim DC wiring/lighting is not approved unless it is UL listed and would have transformer or some sort of protection.

DC wiring in a home is limited to the battery to inverter/charge controller in non conditioned space (garage/shed/etc) for insurance purposes. Most insurance people won't know this until there is a claim. At that time they will find out and decide whether to cover you. Most building inspectors will know not to run DC wiring. They are not trained in it and the building code is almost entirely AC wiring.

The loss between AC and DC wiring is negligible in a well designed power system. If you are on the edge here and do not carry insurance it is understandable but one day you should endeavor to make changes to not have this issue, I think!

[Don_P]

The electrical guys can correct me but I think I recall that low voltage wiring cannot run along regular AC wiring... 2" minimum separation ?

LED is a DC device, they actually have to perform magic to make them run on AC

[Dave Sparks]

Have not seen any LED DC wiring in the wall that is approved by UL for residential. External to the wall it still needs to be UL listed and the instructions with the device followed.

The magic is just an integrated circuit that cost less than a stick of gum. It can buck/boost convert up or down in voltage, DC or AC. The LED device is UL listed.

I have been hired to look at Offgrid homes that had fires a half a dozen times or so. One was so hot all I could find was steel enclosures with UL stamps on them. All of the aluminum and copper was in a melted pile on the ground buried in ash.

You can always exceed the code or quality, but the minimum requirements do save lives. Also if you are going to pay for insurance you should know that they will look very carefully at remote offgrid homes in a claim. Many of my California clients including myself are self-insured. We have been before and when it is affordable we may again insure.

[MountainDon]

Dave, do you find that some people seem to forget about fuses on their DC device wiring?

I have a couple of neighbors with remote off grid solar similar to what we have. I seem to be the only one with DC breakers and/or fuses. 

[Dave Sparks]

Well I am going to say yes this is common with cabin type wiring. I am not trying to belittle cabins compared to homes. It seems less of a concern as so few are insured or have a high value.

I mainly help folks do homes or transition from a cabin type affair to living in a home full time. Either way DC wiring can only be where I outlined above if you want to have an insured and super safe home. Hiding it is the wall is a nightmare waiting to happen.

DC is much more dangerous than AC firewise!
One needs the skill to do it properly. It can be learned.

Big day here in Mariposa! The utility is going to shut down power again due to 30mph winds. I have 4 Firman dual fuel gensets in my truck from costco. I might make some money but at such a sad state of affairs. They say 10 years of outages to fix the grid in this state.

Only in California could it get this bad with a one party controlled state government.

[DaveOrr]

Dave, do you find that some people seem to forget about fuses on their DC device wiring?

I have a couple of neighbors with remote off grid solar similar to what we have. I seem to be the only one with DC breakers and/or fuses. 

Don
I think that there are a lot of people that don't understand electrical period.
I'm lucky in that I worked in low voltage DC electrical for many years and know how to do things right.
My plan for DC distribution is one of these. https://www.bluesea.com/products/1223/12_Volt_DC_12_Position
Not cheap but done right. In fact it will cost more than my AC distribution panels.

[MountainDon]

Just know that insurance companies can refuse claims even after you may have paid them years of premiums.

[Dave Sparks]

Just know that insurance companies can refuse claims even after you may have paid them years of premiums.

Definitely Agree ! And they take better inspection pictures than real estate agents for a reason

With the fire issues in California we lost our insurance again and put the money (about 5K$) for this years premium into further hardening for wildfire.

Blue Sea is fine for a Marine application. Definitely not listed for residential. As long as you go in with eyes wide open and are not worried about resale value, insurance, and do it right you will be fine Dave. It is a beautiful place you have so enjoy it!

The inverter loss is pretty small these days but it is there. Since you have not done this yet, consider doing both a DC and AC panel? We did this here in the old days when we were building. Over the years we abandoned the dc and made it into a low voltage 12V outside lighting and drip water pumping for the garden. We abandoned  all of the conditioned space DC wiring.

[old_guy]

Thank you, everyone.  Terrific dialogue.  I was looking at DC circuits for LEDs to avoid possible conversion losses, reduce AC to DC circuit failures by reducing numbers of conversion circuits, and reduce possible noise from the ac/dc fixtures.  It appears that my concerns are much greater than the potential problems, and that DC circuits would introduce a very real insurance problem.

Unless there is strong evidence/experience to the contrary, I will continue to wire for AC, and let the approved fixtures/bulbs do the conversions needed for the LEDs.  I expect that standard AC is where most of the near future LED progress will be made.

[Dave Sparks]

There is always room for improvement, but LED's have been "done" as far as anyone living offgrid for well over 5 years now

Almost the day they came out (at costco) LEDs were far superior to CFL's that were used for decades offgrid.

I use costco as an example of a product being commercially viable.

[yankeeredneck]

The electrical guys can correct me but I think I recall that low voltage wiring cannot run along regular AC wiring... 2" minimum separation ?

LED is a DC device, they actually have to perform magic to make them run on AC

When I ran low-voltage; you can run parallel a max of 12 inches and need to be at least 6 inches away from it. You can cross just never run right with it. A rule of thumb was opposite side of the bay than the high-voltage within the same bay

[Dave Sparks]

When I ran low-voltage; you can run parallel a max of 12 inches and need to be at least 6 inches away from it. You can cross just never run right with it. A rule of thumb was opposite side of the bay than the high-voltage within the same bay

Each AHJ will/may have different thoughts on this so it needs to be checked first if inspected.

[firefox]

I am assuming (yes I know) that this is to prevent the ac from inducing currents in the dc wiring, or are there other reasons?

[Dave Sparks]

There are plenty of reasons to not run AC and DC wiring inside walls. First is it may not be allowed in your county or AHJ. Since it can't be inspected after the wall is closed, it does present the constant danger of someone driving a nail or screw in or some other bad thing, like a metal picture frame causing a fire. Home Insurance issue down the road if it is not approved in your area.

I think you can hide the DC wiring outside the wall. After 30 years of living on inverter power the conversion loss of a DC powered inverter is acceptable and not a big deal if designed in. In my opinion this is the only place where DC battery to AC producing inverter should happen for residential power.

In electronics we often do a" failure mode and effects analysis". This is where one takes all of the known devices and goes through a map of shorting, opening, and joining all of the possible combinations of inputs, outputs, and any control wiring. 

Best to leave the DC outside where it can be seen.

[firefox]

Thanks Dave, So it's not about the electrical physics, but about the the human interaction. I really appreciate your knowledgeable input on this subject!

[Dave Sparks]

Welcome!  What is the MVPA BTW?  A motor vessel?

[MountainDon]

Welcome!  What is the MVPA BTW?  A motor vessel?

    Moderate to Vigorous Physical Activity?

Motor Vehicle Preservation Association ?

[firefox]

Close Don
Military Vehicle Preservation Association