connecting direct to AC house wiring question

NScooknet

Hello,

I am just in the process of upgrading my very small solar power system, to one that will hopefully run a couple things in my house, and I was wondering about these grid tie inverters.

I called out local power company (Nova Scotia Power) and asked about these, and they informed me I would have to go through this huge lengthy process of signing forms, approvals, installation of a reverse meter system, and then, have the inverter (a very expensive one!) wired into the system by Nova Scotia Power.

When I explained that I had only a small setup, and was just wanting to just plug it into the wall from the cheap little inverter, such as the ones available on ebay, they said I could not do that. They actually told me those inverters are a fire hazard, and are not allowed to be used in Canada.

So, I sat and thought for awhile about how to get the tiny bit of solar power I would generate into my house from the back room where the setup was, and I've come up with only a few possibilities.

I live in a rental house, so I cannot modify anything, or fish cables through the wall to other rooms in the house, so what I was wondering is what would happen if I were to turn off the breaker to one of the plugs in that back room were the solar setup is located, and then connect a male to male patch cable from my inverter output (which I have not purchased yet) straight into that wall plug receptacle of the house that has the breaker turned off in the main breaker box for the house?

The point of this would be one circuit in the house (that happens to also supply power to my living room) would be supplied power to by my solar setup, while the rest of the house ran on regular old expensive AC power from the power company.

Do you foresee any problems with this kind of setup, as long as I made DARN sure that breaker NEVER got turned on? I know it would instantly roast my inverter wouldn't it?

If I did this, any old inverter would do right? I wouldn't need a "grid tie" inverter for this kind of setup would I??

Thanks in advance for your suggestions!

Chris

petertearai

Re: connecting direct to AC house wiring question

One Sugestion. Dont do it.

BB.

Re: connecting direct to AC house wiring question

NScooknet wrote: »

I am just in the process of upgrading my very small solar power system, to one that will hopefully run a couple things in my house, and I was wondering about these grid tie inverters.

As you are finding out--There is no cheap/small/safe way to install GT inverters in a home. In electronics, we say "pick any two".

I called out local power company (Nova Scotia Power) and asked about these, and they informed me I would have to go through this huge lengthy process of signing forms, approvals, installation of a reverse meter system, and then, have the inverter (a very expensive one!) wired into the system by Nova Scotia Power.

Yep, there is no safe way of installing small grid tied systems into a home. The solar panels should be mounted safely (if on a roof, you may need a professional/civil engineer to do load calculations and sign off). Any exposed wiring needs to be in conduit and/or behind a locked fence. Need permanently attached grounding. And a hardwired dedicated circuit back to the main panel (plugging into a home outlet can make "too much current" available and cause a home wiring fire (perhaps not with your small system--but people do keep adding over time).

When I explained that I had only a small setup, and was just wanting to just plug it into the wall from the cheap little inverter, such as the ones available on ebay, they said I could not do that. They actually told me those inverters are a fire hazard, and are not allowed to be used in Canada.

Yes, you can purchase "Power Jack", "SWEA", and other brands of "Plug&Play" GT inverters. None (that I know of) are "LISTED" devices by UL/CSA/NRTL's which is a requirement for your power company/local building inspectors.

The closest you will find that are legal is the Enphase (and similar) micro GT inverter family:

Enphase Microinverters for Grid-Tie Solar Systems

These are not that expensive, are safe, and reliable. However, you still have the whole wiring/approves/mounting issues that still cost $$$$.

So, I sat and thought for awhile about how to get the tiny bit of solar power I would generate into my house from the back room where the setup was, and I've come up with only a few possibilities.

I live in a rental house, so I cannot modify anything, or fish cables through the wall to other rooms in the house, so what I was wondering is what would happen if I were to turn off the breaker to one of the plugs in that back room were the solar setup is located, and then connect a male to male patch cable from my inverter output (which I have not purchased yet) straight into that wall plug receptacle of the house that has the breaker turned off in the main breaker box for the house?

Yes, it can be done and probably will work for awhile. However, the plug you are talking about is in the industry known as a "suicide cord". Care to guess why?

In any case, it sounds like you are looking at the wrong inverter. Off grid inverters (typical that most people use for AC power from a battery bank) have a female receptacle and to connect to your home wiring, you would use a suicide cord. However, when you do this, you will kill the off grid inverter, and possibly lead to fire/death.

A true plug&play GT inverter would already have a male plug and could use a standard extension cord. Again, this, at the very least violates a whole host of laws and safety regulations.

The point of this would be one circuit in the house (that happens to also supply power to my living room) would be supplied power to by my solar setup, while the rest of the house ran on regular old expensive AC power from the power company.

Are you familiar with a computer UPS (uninterruptable power supply)? Think of your "solar power" system like a UPS. AC power to Inverter/charger/battery bank to your load. And attach a solar panel + solar charge controller to that battery bank.

Regarding saving money--or not--Unless your power is on the order of $1-$2 per kWH, going "off grid" power is going to cost way more than utility power.

If you wanted a real "Hybrid" power system (Utility power + Grid Tied backfeeding utility + emergency off-grid power -- AKA a whole house UPS system)--You may be looking at $0.45 per kWH (rough estimate). In California, only the heaviest of power users (homes with A/C turned on for summer afternoons, etc.) will reach the $0.52 per kWH price point for power. But, that is for a 4-6kW Hybrid inverter + battery bank. Still need to look at cost of solar panels + solar charge controller.

Do you foresee any problems with this kind of setup, as long as I made DARN sure that breaker NEVER got turned on? I know it would instantly roast my inverter wouldn't it?

Yes, lots of problems. I have seen breakers with locks on them to prevent being powered on (service personnel only). But, there are still lost of potential safety/grounding issues (plus, were are you going to install the battery bank, and will you have venting for hydrogen gas and electrolyte mist?).

If I did this, any old inverter would do right? I wouldn't need a "grid tie" inverter for this kind of setup would I??

Not really--At the very least you need to look at using a TSW (true sine wave) inverter (the more costly type) that does not exceed your branch circuit current rating (~12 amps at 120 VAC typical). A MSW (modified square wave) inverter is typically not isolated and will make your battery bank +/- hot with respect to building ground.

Also, many homes use a common Neutral for Line1 and Line2 (split phase 120/240 VAC for North American homes). If you have a common (shared) neutral between your one "solar circuit" and another circuit in the home, it is possible to overheat the common neural and cause a wiring fire. You would have to trace the wiring to figure out if your home uses a common neutral or not (and if a common neutral, then there is no safe way of "fixing this" without rewiring anyway).

Chris--There is no real good way of doing an Integrated Solar Power System in a rented home. Some people do an emergency power system that runs separate from the home wiring--But that is not going to save you any money on your power.

You best bet is to spend money on conservation (fridge, laptop computer, heavy drapes over windows, turning stuff off--such as the entertainment system and desktop computers when not in use, etc.).

Doing it wrong can cause you a whole host of problems:

Panel Fire Question
ENERGY: Solar fire raises questions about panel safety

There are still fires even when the home owner does things "right"...

-Bill

NScooknet

Re: connecting direct to AC house wiring question

Hi BB,
Thanks for the wealth of info you've offered here. I appreciate your willingness to give advice.

I have to say that I am a bit confused about your advice, as it almost seems as if your trying to actually discourage me from building my solar setup bit by bit.

I truly do see the logic in doing things right the first time, but I get from alot of people offering advice that if I cannot afford a large elaborate system, and sinking thousands of dollars into that system up front, I shouldn't bother with solar at all.

My goal is to build a simple system bit by bit, adding on as I can afford it, and keeping it as portable as possible.

I totally get the cost vs price of power from the power company, but our situation here is not counting on the power company being able to reliably deliver power, thus the need for a backup, as meager as it may be.

Our need for a backup power source is based on two things, first, we lose our power alot due to bad weather, in fact, I'm waiting to lose it as we speak, a bad ice storm is occurring outside right now! It's nice to simply have LED lighting run through the house with extension cords, and the ability to run a pump to get water from our well to flush the darn toilets until power returns again.

Second, I am one of the believers in the possibility of either an economic collapse and or a solar maximum interfering with the ability of the power companies to actually deliver power here, so at the very least, I need a system that will run my 12V well pump, we can last a long time without many things, but if we don't have a way to get fresh water, my family and I are toast.

I am familiar with the "suicide cord" name, I'm actually an electronics tech, but suffered a brain injury some years ago, so sometimes I need a bit of help with things...lol.

The reason I thought this may be viable, is because in the past, I used one of these cords to connect a gas powered generator to my house in times of power outages after switching off the entire breaker box. I didn't think it would be all that dangerous to connect the output of a 2,000 - 3,000 watt inverter in this manner if I ensured the breakers in the fuse panel were off, and nobody messed with them.

I have had 3 deep cycle marine batteries connected in parallel connected through a cheap controller "slowly" charged by two 15W panels for many years now, and have never had an explosion from hydrogen gas before, are you saying this is a dangerous setup I have? I have my batteries in a secure location, free from possibility of spark or flame from anything and in a well ventilated back room of my house, is this a dangerous thing to do? Where am I supposed to put them?

Would you recommend sealed gel cell batteries instead??

Currently, I have these two 15W panels mounted to the front (south facing) of this house, right on the siding, and had simply planned on adding a couple more higher wattage panels, and a better controller, as well as a few more batteries to give better capacity, this can all be taken with us when we leave here.

Rentals suck. I cannot mount to the new roof they just replaced, but mounting to the front of the house actually seems just fine, and the landlord has no problem with it at all.

I don't have much flexibility, so I just need to make the best of my situation, doing nothing is not really an option, even if it's not an ideal situation.

Looks like I may be limited to simply running extension cords through the house in times of outages from the inverter I guess.

Thanks again for your advice!

Chris

BB.

Re: connecting direct to AC house wiring question

Good Evening Chris,

NScooknet wrote: »

I have to say that I am a bit confused about your advice, as it almost seems as if your trying to actually discourage me from building my solar setup bit by bit.

I am sorry--I guess I was not very clear. YES, building a system up bit by bit is not usually a good idea.

I truly do see the logic in doing things right the first time, but I get from alot of people offering advice that if I cannot afford a large elaborate system, and sinking thousands of dollars into that system up front, I shouldn't bother with solar at all.

My goal is to build a simple system bit by bit, adding on as I can afford it, and keeping it as portable as possible.

I have a 3.5 kW grid tied system on my home. More than enough for me to break even on my electrical bill have have a lot left over for that small electric car (if that ever makes sense). But portable--It is not.

I totally get the cost vs price of power from the power company, but our situation here is not counting on the power company being able to reliably deliver power, thus the need for a backup, as meager as it may be.

And this is the reason that Grid Tied--which is the most cost effective and reliable of solar PV power--is not good for emergency power use. It only functions when the grid it up and running.

Our need for a backup power source is based on two things, first, we lose our power alot due to bad weather, in fact, I'm waiting to lose it as we speak, a bad ice storm is occurring outside right now! It's nice to simply have LED lighting run through the house with extension cords, and the ability to run a pump to get water from our well to flush the darn toilets until power returns again.

Emergency power--that is a different application. There are ways to "creep up" on your requirements that allow you to spread your investment out over time and tailor it for your needs.

First, defining your power needs. LED's are great--Good amount of light for very little power. Standard Well Pumps--Terrible for off-grid power systems--High surge current, short heavy loads scattered throughout the day. Requires big batteries and an inverter (which sort of kills the portability unless you plan on mounting them on a trailer).

Conservation is usually the best place to start. Using the in-well pump and an inexpensive generator to fill a cistern (or possibly several large pressure tank that can store a day's worth of water). If you go with the cistern, you can get a small 12 or 24 VDC pump that (with or without a small pressure tank) will supply your minimum in-house water needs very easily with a smaller battery bank. Many people will setup a "by-pass" system of valving to allow the 120/240 VAC well pump to run normally, and switch in the DC pump for emergency/backup use.

So--Now that you minimized your power needs (lights, radio, laptop computer, cell phone charger running off a small/efficient MorningStar 300 Watt TSW inverter and a few "golf cart" batteries) and, I would suggest, a Honda eu2000i (1,600 watt) or Honda eu1000i (900 watt) inverter/generator (very quiet and fuel efficient) + 120 VAC battery charger for your golf cart batteries. See this thread for Charger details:

Question about battery charger selection with EU2000 generator.

So, my suggested order for "building out a system"

1. Measure your "emergency" loads with a Kill-a-Watt meter or equivalent
2. Figure out how to reduce "large surge loads" (water pumping typically) (propane, diesel, natural gas, gasoline depending on your needs/availability)
3. Get a Genset and emergency fuel supply with an AC Transfer Switch (or extension cords)
4. Install a Battery bank + inverter sized to your loads
5. Install solar panels + solar charge controller as funds/conditions permit

Second, I am one of the believers in the possibility of either an economic collapse and or a solar maximum interfering with the ability of the power companies to actually deliver power here, so at the very least, I need a system that will run my 12V well pump, we can last a long time without many things, but if we don't have a way to get fresh water, my family and I are toast.

Good--if you can get water with a 12 volt/small pump, that is a huge win. Remember that few DC pumps can draw water more than 10-20 feet from a well. Then you need to look at in well pumps or other solution (rod pumps, etc.).

The reason I thought this may be viable, is because in the past, I used one of these cords to connect a gas powered generator to my house in times of power outages after switching off the entire breaker box. I didn't think it would be all that dangerous to connect the output of a 2,000 - 3,000 watt inverter in this manner if I ensured the...

There is the "legal" answer--Any interconnects to the home wiring must be done with a Transfer Switch and usually requires a licensed electrician and permits. The safe answer is you need some sort of transfer switch (unless you are using a high end inverter or hybrid inverter which usually includes a transfer switch).

There are vendors that sell transfer switches the plug underneath the utility meter--probably the easiest "whole house" transfer switch (just need to arrange with your utility to pop the meter and plug in the transfer switch--I don't know if permits are required or not).

Most solutions will not power your entire home--but just a few critical circuits. Even powering a single fridge from a battery bank requires a fair amount of batteries and a 1,500 watt or larger inverter.

I have had 3 deep cycle marine batteries connected in parallel connected through a cheap controller "slowly" charged by two 15W panels for many years now, and have never had an explosion from hydrogen gas before, are you saying this is a dangerous setup I have? I have my batteries in a secure location, free from possibility of spark or flame from anything and in a well ventilated back room of my house, is this a dangerous thing to do? Where am I supposed to put them?

When talking about a large enough system to operate a good sized load (around 1-3kWH per day)--500-1,500 watts of solar panels and 640 to 1,900 AH @ 12 volts (example) of battery bank (or ~6 to 18x 6 volt 220 AH "golf cart" batteries). This is just a range based on zero knowledge of your needs by me--Just an estimate of the size of a system for for running a "typical" home on emergency power for weeks/months at a time.

Would you recommend sealed gel cell batteries instead??

I would suggest starting with "inexpensive" but good quality "6v*220 AH" golf cart (or larger if you want a "big" system) flooded cell batteries and see how it works for you. In ~3-6 years or so, you can get a more expensive set of flooded cell or even AGM batteries once you have your loads dialed in. I would suggest staying away from GEL for an off-grid power system.

Currently, I have these two 15W panels mounted to the front (south facing) of this house, right on the siding, and had simply planned on adding a couple more higher wattage panels, and a better controller, as well as a few more batteries to give better capacity, this can all be taken with us when we leave here. Rentals suck. I cannot mount to the new roof they just replaced, but mounting to the front of the house actually sees just fine. I don't have much flexibility, so I just need to make the best of my situation, doing nothing is not really an option, even if it's not an ideal situation.

Emergency Power

Basically a very long thread that starts from the beginning with a few vague requirements through design and assembly for a "portable" solar RE off-grid power box (around 130 Watts of solar panel and a single 100-150 AH 12 volt deep cycle battery--Note: Marine batteries are not usually very good for deep cycle applications).

And here is another example by Mike90045 called the Solar Monolith:





Update pictures/information here.

Looks like I may be limited to simply running extension cords through the house in times of outages from the inverter I guess.

Not trying to throw cold water on your project--Just trying to backup a bit and get a better definition of your needs.

Solar has never been cheaper--but it will never be cheap. If you could live with a backup genset for a while--They are usually the most cost effective solution for short term outages.

Remember, for off-grid power, very roughly, you will need to replace the batteries every 5-10 years, and the charge controllers/inverters every 10+ years.

-Bill

petertearai

Re: connecting direct to AC house wiring question

Sorry to give a one line reply, but what you were suggesting was not safe .
As for building a solar system Bill has some great advice.If I was to reaffirm some of it,I would get a Quality generator 1st as that will always be of use, and be portable to any new accommodation. Solar power can be a very interesting thing, this forum and moderators are fantastic.
Regards Peter

NScooknet

Re: connecting direct to AC house wiring question

Thanks Peter, but I'm trying not to rely on fossil fuels at all, as they just might not be available in the near future if things "melt down", and a generator requires me to build a whole additional outdoor storage and operating enclosure for it, not to mention that they are REALLY noisy unless you buy an expensive one.

BB.

Re: connecting direct to AC house wiring question

I am not sure there will be a total meltdown... I would guess that it will be more like many areas in the world... 3-6 hour outages in the afternoon-evening. A "UPS" type system is very common in those regions (AC power to Inverter/Charger + battery bank).

Again, if you are planning on longer outages (say your place is very rural), then looking at "Forklift" type batteries with 20+ year life (plus spares for inverter, charge controller, etc.) is not a bad way to go... Realize that forklift batteries are not quite as efficient and will require a slightly larger array and a fair amount of distilled water (several gallons per month?) over regular deep cycle batteries (typically 5-10 year life).

-Bill

icarus

Re: connecting direct to AC house wiring question

NScooknet wrote: »

Thanks Peter, but I'm trying not to rely on fossil fuels at all, as they just might not be available in the near future if things "melt down", and a generator requires me to build a whole additional outdoor storage and operating enclosure for it, not to mention that they are REALLY noisy unless you buy an expensive one.

Just something more to think about. A Honda EU1000 generator is so quiet you can't hear it right outside the window, with the window closed. It requires no shed, since it is portable, weighing under 30 lbs, cost ~$800, and will deliver 800 watts 24/7 for about 1 Litre of fuel every ~6 hours. The same wattage of PV, and battery bank system, (which will only deliver real power ~4 hours a day, at. Net deficiency of ~50% might cost $5,000. One has to ask, how unstable is your gird,, and does battery based PV make any economic sense for emergency power. (Usually not!)

Tony

rgk1

Re: connecting direct to AC house wiring question

NScooknet, not sure if you can find a work around since you rent. But, when I need to use my solar during an outage, I plug an extention cord from the outlet on the outside of the shed where my system is located to the inlet box I have attached to the outside of my home. There are two of them. One goes to a dedicated outlet behind the fridge, and the other to a dedicated outlet for tv, sattelite, lamp, etc. No grid tie, no permanent electrical connection from solar to home, no extention cords across the floor. Who knows maybe you could get the owner to consider it a worthwile upgrade and let you do something similar.Attachment not found.

NScooknet

Re: connecting direct to AC house wiring question

icarus wrote: »

Just something more to think about. A Honda EU1000 generator is so quiet you can't hear it right outside the window, with the window closed. It requires no shed, since it is portable, weighing under 30 lbs, cost ~$800, and will deliver 800 watts 24/7 for about 1 Litre of fuel every ~6 hours. The same wattage of PV, and battery bank system, (which will only deliver real power ~4 hours a day, at. Net deficiency of ~50% might cost $5,000. One has to ask, how unstable is your gird,, and does battery based PV make any economic sense for emergency power. (Usually not!)

Tony

I spent alot of time a few years ago shopping around for a cheap generator that would be useful enough to power things in case of emergency, and I ended up with a Coleman 6500W generator that was SO noisy that the neighbors could hear it 5 miles away! It totally sucked.

Then I realized it had to be outside, and venting it with a hose from the muffler to outside when it was in my basement was not a safe way to run it, and then, I needed to build a small shed outside for it with insulation to try to muffle the noise. I then realized I had to install a proper hookup to the house power, which would have been $500 for the switch, and a lot more money for an electrician to install it. Ultimately it was stolen because it was outside where thieves could get at it when I wasn't home, so I'm a bit leery of going with a gas generator again.

There's also the problem of storing the gas, as I said, I don't have a shed, and having gallons of gas stored in my small back room in the house is not a safe option.

One issue we have here is cold weather, north eastern Canada has some freezing cold winters, so keeping my solar setup outside in a shed worries me, not to mention i don't have a shed. Yes, living in a rental really has it's limitations.

After reading some of this thread, I'm now worried about battery storage, I don't want an explosion in my home. Where the 3 deep cycle marine batteries are currently located are in the back "mud room" of this tiny house, next to the back door, which leaks cold air terrible, but I guess that provides some ventilation...lol

This is why I thought about sealed gel cell batteries, but i was told they aren't great for solar power, even though Canadian tire sells them as part of their "eliminator" solar accessories. Those things are $299 each, geesh.

I think high maintenance batteries like the forklift variety might be asking for trouble in this house, the room is about 6 x 10 feet or so, it's also where I make my home brew beer, hehe.

So far I've never had an issue with these batteries, they are maintenance free Canadian tire brand marine deep cycle cells, 160 min/ 100ah. I've noticed in the past few months however that there seems to be some leakage around the covers on top of the battery, and the positive terminal is all yellow and corroded now, so I'm not sure if this indicates a problem or not, I only have a cheap $20 ebay Chinese solar charger and two 15W panels attached to that controller, so maybe the controller is the issue?

I can't see it over charging the batteries, but maybe as I'm only really using the system for lighting in that back room currently. these batteries are now about 5 years old or so.

I actually used to own a home a few years back, and at that time had this very system installed and working well, had the two 15W solar panels mounted on my roof, and had a better controller (that since died for some reason) connected to these batteries in the shop in the back of the house, and I drilled a hole from the shop into the living room and installed a dedicated solar 110V receptacle.

At that time I also had a Canadian tire power box connected to the marine cells also, and used the internal inverter (a 1200W stepped inverter) to supply the 110v to that outlet in the living room.

It was enough to run my TV, home theater system, and also the satellite receiver, but there were constant horizontal lines running through the screen from the crappy inverter...lol.

Thanks again for your advice!

Chris

icarus

Re: connecting direct to AC house wiring question

Chris,

Do yourself a favour and go by a Honda dealer, (or Yamaha) and look and listen to a Eu series genny. The difference between such a unit in both noise and fuel economy is the difference between your 1929 Model A, and your current car!

These units are small enough to be hand carried, you can store them in side empty of fuel, keep a 20 litre can of fuel for emergencies, and run a couple of extension cords to special loads, like fridges, freezers, TV, computer etc. For the one or two time a year (if that) even if you have to run it for a week, you are still further ahead with this set up vs a small battery PV, both in cost, and in performance.

Now if you are worried about "end of the world scenarios" then you are on your own to make a choice.

Tony

PS. Your maritime cold is nothing on ours! We were -26 two nights ago,, which is sort of above average for us! That's why keeping the genny indoors, ideally empty of fuel, allows it to start easily in the cold.

T