Alternative power for the shop

D

deker

Joined
Nov 14, 2005
Messages
3,496
So, my wife has decided that it's time I just get my shop power problems solved. Right now I'm running via some large extension cords run from the garage. The reason is that to extend power from the house is about a 175ft. trenched-in run, and I'd have to have the main to the house upgraded as well. Last time I looked at it I was looking at about $10k to get things run to the shop...before I wire the outlets, etc in the shop.

Soooo, I'm looking at alternative power options. The shop is completely un-shaded and so one option I'm looking at is solar power. I'm trying to figure out how to size a system, but all the online calculators I can find are designed around the concept of adding solar to a house. I can't readily equate large induction motors to hair dryers and air conditioners, so I'm hoping somebody who knows a bit more about this might be able to help me out. I'm kind of thinking that because of stuff like a 7.5HP compressor, hydraulic press, EvenHeat, and the eventual mills, lathes, etc. that solar isn't really going to be cost effective. However, I told my wife I'd check into it since there are so many government programs to help with alternative energy installations.

I'm also open to any other suggestions folks may have for the best way to electrify the shop.

Thanks,

-d
 
Last edited:
Why do you need to rewire the line to the house? When I ran electricity to my shop, about an 80' run, my electrician was able to run the wire from a 200 amp circuit breaker box in the shop to the meter on the side of the house. Opening the meter, you'll see that there are extra clips in there so you can attach another leg or two after the meter.

All perfectly legal and didn't have to fret with anything in the house at all. Considering how old the house is, I'm very very glad I didn't have to get into that mess.

Just make sure that you get a heavy gauge wire so you have plenty of electricity for your needs, including such things as welders or ovens.

My total cost, labor and materials, was under a grand.
 
Perhaps you should concider doing your own wiring. There is lots of information around and most if not all areas will allow you to legally go ahead after you get a permit that usually is not expensive. You can probably dig a trench and lay the necessary type of wire which is an expensive type. The depth you have to go will be what the area demands. Frank
 
Code in my area calls for three feet of cover over buried electrical lines. Some places mandate use of warning ribbon one foot above the buried line so you hit it first, but that varies.

I've not heard of a service line to the house being too small to support a shop. Sure, large production facilities need three-phase power a lot of times, but a house shop shouldn't have so much draw on it that you would overload the service line from the transformer to the house.

Is your service line aerial or buried from the transformer?
 
VaughnT said:
Why do you need to rewire the line to the house? When I ran electricity to my shop, about an 80' run, my electrician was able to run the wire from a 200 amp circuit breaker box in the shop to the meter on the side of the house. Opening the meter, you'll see that there are extra clips in there so you can attach another leg or two after the meter.

All perfectly legal and didn't have to fret with anything in the house at all. Considering how old the house is, I'm very very glad I didn't have to get into that mess.

Just make sure that you get a heavy gauge wire so you have plenty of electricity for your needs, including such things as welders or ovens.

My total cost, labor and materials, was under a grand.
Click to expand...
+1
I'm getting ready to do this myself.
call dig-safe
rent trencher
dig trench, drop in 2" grey carlon PVC pipe (glue all your seams)
pull wire. (use a shop vac to suck a pece of sponge with string/baling twine attached, use that to pull a rope, use rope to pull your 4-0 triplex or 3-0 copper (if it's a 200 amp service)
connect to breaker box with main breaker turned off, then connect to meter.
fill in trench.
wire shop.

good luck!
 
VaughnT said:
Code in my area calls for three feet of cover over buried electrical lines. Some places mandate use of warning ribbon one foot above the buried line so you hit it first, but that varies.

I've not heard of a service line to the house being too small to support a shop. Sure, large production facilities need three-phase power a lot of times, but a house shop shouldn't have so much draw on it that you would overload the service line from the transformer to the house.

Is your service line aerial or buried from the transformer?
Click to expand...



My house is 36 x 50 with a 100 amp service, My shop is 16 x 32 with a 200 amp service. Seperate lines and meters. If I ran my kiln and the welder on my house service the lights would go out.
Del
 
My little rental shop complex was built in the 70's and is nice and cheap, but the wiring was a mess because every a-hole hobbyist "body man" and car detailer that had ever rented space in my end of the building where I am and ran out in the middle of the night when they could no longer pay rent did some kind of "wiring" I had by own circuit pulled over 200 feel from the main panel and had my own panel installed with both 110 and single phase 220 and it cost me around $2000. Where it can get a tad expensive is if you need multiple 50 amp 220 outlets. Remember to check how much power you actually need at one time. While you may have 5 or 6 machines that draw 20-30 amps, how many of them are going to be running at the same time? You have to have a sufficient number of slots in the box for your 220 circuits, but that doesn't mean that you can't unplug one machine and plug in another. I have my press and hammer using the same outlet. If I happen to need to plug them both in at the same time, I can just unplug my Paragon and plug the hammer into that outlet.
I guess the actual answer to your question is that I suspect that if you tried to power your shop using solar, I wouldn't know if you would run out of money or roof space first, but you would ru out of both long before you could install enough panels to power your shop gear I would think.
 
VaughnT said:
Why do you need to rewire the line to the house? .
Click to expand...

Because we've got a fully populated 200A box in the house, and I'd like to have a minimum 100A service for the shop so I can run a rotary phase converter at the same time as I run the kiln, while possibly having the compressor kick on. At the end of a longish run like I need to get there, the voltage drop from induction motors firing up is significant...Soooo, power company needs to upgrade me to 400A at the house. Also, the interior panel here was manufactured by a company that's no longer in business and a single 15A breaker for it can run into the hundreds. I'd rather not replace the entire house's panel to pull a sub-panel since that would cost as much as upgrading the house service. If I upgrade the house service it can be connected to a 400A disconnect w/ 2x200A breakers at the head end outside so that the house gets 200A (and nothing inside has to be changed) and the shop gets 200A.

Frank Niro said:
Perhaps you should concider doing your own wiring. There is lots of information around and most if not all areas will allow you to legally go ahead after you get a permit that usually is not expensive. You can probably dig a trench and lay the necessary type of wire which is an expensive type. The depth you have to go will be what the area demands.
Click to expand...

I can do it myself, but the cost of renting the trenching equipment would likely offset my calling in the excavator who did the work for my shop. Also, because of the soil being mostly rocky here I can't run direct burial cable, so I have to run in conduit. I've never pulled wire that big through conduit. I know it takes special equipment to do, so more money in tool rental. I've got some "buddy points" with a couple of electricians who can do it, but they won't be doing this much work for free...Either way, I have to hire an inspector to sign off on it regardless of who does the work. It all adds up.


VaughnT said:
Code in my area calls for three feet of cover over buried electrical lines. Some places mandate use of warning ribbon one foot above the buried line so you hit it first, but that varies.

I've not heard of a service line to the house being too small to support a shop. Sure, large production facilities need three-phase power a lot of times, but a house shop shouldn't have so much draw on it that you would overload the service line from the transformer to the house.

Is your service line aerial or buried from the transformer?
Click to expand...

Ariel line to the house, and a larger service would have to be trenched according to the power company. Then I still need to trench to the shop. I COULD put a separate service to the shop, but since it doesn't touch the house it would be classified as commercial, have rate multipliers based on peak use, and I'd have to pay additional monthly account maint. fees. Oh, and I'd have to trench from the pole or install another pole in the middle of the yard (we've already got one).

That's some of why I'd like to keep it disconnected from stuff. A generator is a possibility (and could give me 3ph!), but my wife doesn't believe that the hourly costs would effectively offset the extra investment of other methods like solar, etc. So, I'm trying to see what options are available and do my due diligence.

-d
 
jdm61 said:
Remember to check how much power you actually need at one time. While you may have 5 or 6 machines that draw 20-30 amps, how many of them are going to be running at the same time? You have to have a sufficient number of slots in the box for your 220 circuits, but that doesn't mean that you can't unplug one machine and plug in another.
Click to expand...

I understand that bit completely, but let's assume the following "would sure be nice" scenario:

Some day, Deker will hold a small hammer-in at his shop (not too unlikely, my wife has suggested I do this multiple times). So, let's just say that we have something going on in the hot shop and the cold shop at the same time since multiple people are likely to be working at once. I could absolutely see a compressor kicking on (7.5HP motor) while the press was running (5HP motor), with a kiln running, and possibly a belt grinder (2HP motor or so). Add in lights, fans, and the long run that causes voltage drops when induction motors fire and I'm pushing the limits of a 100A circuit. That's assuming I'm not also possibly running a 10HP rotary converter for something... Since the next upgrade point for the house is 400A, I may as well take 200A to the shop.

Oh, and I NEVER want to have to upgrade this or wish I had gone bigger for some reason. I'm planning to stay in this shop for a good long while. :)

-d
 
Deker,
I have been to your place and you have one great advantage.....no neighbors.
Check Craig's list and the other sellers, and buy a BIG generator, preferably a diesel or propane powered one. Set it up behind the shop with a shed roof over it and put a fuel tank up next to it. When you need to work in the shop, just hit the start button, and shut it off when you are done for the day. Generators are often really cheap from those who purchased one and never used it. I see whole house generator units for sale all the tine for less than the cost of running a new power drop to the shop.

A second advantage will come when the snow storms cut your power for a couple days.
 
There are a couple ways of doing solar power. The cheapest would be a solar panel and inverter kit. The problem with that method is you will only have the amount of power your panels make, and nothing more. A little more expensive route would be to add a battery to the system so you can store power. Batteries can get very expensive, but some are warranted for 10 years.

To calculate the system size, you need to figure out how many Kw/h a month you use.

This place has a lot of info and products, including calculators for whole systems and batteries.

http://www.wholesalesolar.com/

Also be sure to check here for rebates and incentives from the federal government and state government.

http://www.dsireusa.org/

Depending on how much your state gives in rebates, you can end up getting a whole system for less than half the retail price.

I had a company come out and give me an estimate. The entire system would be $25,000. With all the government rebates the price came down to around $10,000, and rebates were applied when you bought the system, not at the end of the year. I had it figured up with my power bill(not accounting for any inflation) and it would pay for itself in 3 years.
 
Living in the land of crunchy granolaheads for years (Ithaca NY) I have seen a lot of people who retrofitted their houses or built new for alternative energy. The investment per watt in solar is astronomical, because you need not only panels which are still stupid expensive, but you need storage batteries and inverters capable of handling your power draw needs. Most people who go solar end up investing in low draw appliances to try to stretch those watt-hours that they have collected. Most people who have whole house alternative energy have set their entire house up to draw less than your compressor.

Electrical panels are relatively cheap (I got a 200 amp Square D for under $200 at Home Depot) I just have to have the electric utility upgrade my service which will run about a grand which is why I haven't done it yet. Don't waste your time trying to run machinery on solar, either run a wire or get a generator

-Page
 
I have power issues until I upgrade my house wiring so I am building my press to be gas powered, the pump doesn't need to be inside, so I'm going to run the hoses through the wall, you can get gas powered compressors

-Page
 
Diesel Generator, sounds horrible but take a closer look. I think there is propane generators too.
 
I say it's not realistic to run shop equipment on alternative power.
some lights or small household appliances maybe.

Wind has much greater capacity than solar panels, but the equipment alone, plus the space it would take to store it would be much more than the new service.

You may try keeping the compressor in the house and just running piping, to the shop to keep that power load in the house instead of the shop.
 
A diesel generator is honestly very high on my list of "feasible". Propane generators are right out. There simply aren't enough BTUs in a gallon of propane to make it as efficient as diesel. I've done my looking here. a 10KW diesel generator is about 1.1gal/hr at 100% load where a propane generator is more like 2gal/hr. The price differential between propane and offroad diesel isn't significant enough to make up the difference. I've also already got a spare 175gal fuel oil tank next to the shop that just needs legs. I also like the fact that if it's wired right it wouldn't be much work to nix the generator and connect to the main from the house in the future.

Now, the downsides. Noise is up there. Unless I spend a pretty penny on a generator with an acoustic enclosure, it's going to be pretty loud. This puts all the cheap milsurp MEP series generators out of the running...civilians never could get the acoustic enclosures from what I understand. I could build an acoustic enclosure I guess so long as I had some pretty serious forced air for cooling. Keeping things relatively quiet will be important because of people here at my house, not so much because of the neighbors. I will also have to deal with bringing quantities of fuel to the tank. If I can run the generator on #2 heating oil it's sort of OK, but offroad diesel delivery ends up costing more than on-road fuel from the pump (I've checked). So, then I need a tote tank and pumping setup to go get offroad diesel a hundred or so gallons at a time...unless I'm hand pumping just the pump will be $400 or so. Add pouring a pad to place the generator on, building an enclosure, and the cost of a decent genny to start and suddenly I'm only $2-3k away from just trenching stuff...Of course, if I plan right I can get switchable 1ph or 3ph so that I can get a bonus of cheaper tools. I also have the argument that with a great big extension cord we can have reasonable back up power for the house in the event of a power outage...

What I'm shooting for is some due diligence on my different options with some documentation and numbers to back me up. For whatever reason my wife is convinced that solar or wind are good options because of tax breaks and rebate programs. I understand that the loads imposed by the machines I'll be using simply make inverter and battery based solutions unreasonable from several perspectives, but I need to back that up. There is also the issue of fuel costs to contend with. All I have for generators are efficiencies at full load to quote, so when I say "a gallon an hour" that immediately translates into "at $3/gal that's $25 a day you're in the shop" where the "magic of free electricity" doesn't cost anything after you install it.

-d
 
deker said:
A diesel generator is honestly very high on my list of "feasible". Propane generators are right out. There simply aren't enough BTUs in a gallon of propane to make it as efficient as diesel. I've done my looking here. a 10KW diesel generator is about 1.1gal/hr at 100% load where a propane generator is more like 2gal/hr. The price differential between propane and offroad diesel isn't significant enough to make up the difference. I've also already got a spare 175gal fuel oil tank next to the shop that just needs legs. I also like the fact that if it's wired right it wouldn't be much work to nix the generator and connect to the main from the house in the future.

Now, the downsides. Noise is up there. Unless I spend a pretty penny on a generator with an acoustic enclosure, it's going to be pretty loud. This puts all the cheap milsurp MEP series generators out of the running...civilians never could get the acoustic enclosures from what I understand. I could build an acoustic enclosure I guess so long as I had some pretty serious forced air for cooling. Keeping things relatively quiet will be important because of people here at my house, not so much because of the neighbors. I will also have to deal with bringing quantities of fuel to the tank. If I can run the generator on #2 heating oil it's sort of OK, but offroad diesel delivery ends up costing more than on-road fuel from the pump (I've checked). So, then I need a tote tank and pumping setup to go get offroad diesel a hundred or so gallons at a time...unless I'm hand pumping just the pump will be $400 or so. Add pouring a pad to place the generator on, building an enclosure, and the cost of a decent genny to start and suddenly I'm only $2-3k away from just trenching stuff...Of course, if I plan right I can get switchable 1ph or 3ph so that I can get a bonus of cheaper tools. I also have the argument that with a great big extension cord we can have reasonable back up power for the house in the event of a power outage...

What I'm shooting for is some due diligence on my different options with some documentation and numbers to back me up. For whatever reason my wife is convinced that solar or wind are good options because of tax breaks and rebate programs. I understand that the loads imposed by the machines I'll be using simply make inverter and battery based solutions unreasonable from several perspectives, but I need to back that up. There is also the issue of fuel costs to contend with. All I have for generators are efficiencies at full load to quote, so when I say "a gallon an hour" that immediately translates into "at $3/gal that's $25 a day you're in the shop" where the "magic of free electricity" doesn't cost anything after you install it.

-d
Click to expand...
If you are going to look at gensets, might I suggest something crazy like looking at a rebuilt marine genset? They are compact and many of them have soundproof enclosures. The only issue might be cooling as most of them have closed loop freshwater cooling systems. but they are designed to be hooked up to a freshwater to raw water heat exchanger. As for the typical diesel/propane/LNG fueled home generator, most of the ones that I have seen of late are enclosed and if it is legal to have one for your house for emergency power under local noise regs, then how could anyone complain about you using it for your shop? Now if you REALLY wanted to get crazy, you could figure out exactly what kind of alternative fuel you could run your genset on. Most better ones can be set up to run on diesel, propane or natural gas anyway.
 
I made a fairly long run of 100 amps 220V without too much trouble. A trencher was rented for $150, digging the trench didn't take an hour. PVC conduit is cheap. I pulled the wire through each section of PVC at a time as I was gluing it together, which simplified things for me. I used larger conduit than I needed to make it easier.

I ran into the same problem with obsolete breakers. So I bought one large breaker of the obsolete design and used it to power a sub panel and have any new lines off the sub.

I don't understand the need to increase your house power capacity to 400 amps. I run both my house and my shop on the same 200 amp service. This includes a large phase converter, large machines, air compressor, HT, big welders etc. Between the house and the shop, there is about 3100 sq ft being air conditioned. The wife runs things like the dryer and the oven. There is a water heater. etc. I'm sure all the stuff combined would exceed 200 amps, but it doesn't all get run at the same time. Every wire and every circuit is protected by breakers properly sized for the wire they're protecting. An overload is unlikely, but if one were to occur you're protected. I don't see the need for capacity to run every thing at once because that never happens.

All told, it cost less than a grand and took about a weekend.
 
Assuming you need to be able to draw only 50 amps120V, at the max load ( easily passed with only a few pieces of equipment running), that is 6000 watts. Last I heard solar panels were about 2-3 bucks a watt....plus the load handling and storage infrastructure can cost a couple dollars a watt more. To deliver 6KW that would cost a lot.

I'm not talking about Home Depot generators. Used industrial generators are often available very cheap. They are real quiet and often have fuel tanks that will allow them to run for a couple days straight. They commonly deliver 20KW or more. I have been offered good condition trailer mounted emergency generators in the 20KW range for as low as $3000.
 
You could easily need about 10 Kw or more of solar to run the shop, (1 Hp = 745 watts, 7.5 +5 +2 =14.5, 14.5 X 745 =10.8 Kw for the hammer-in, plus lighting, etc) and if you use the power grid for backup, you'll need that big electric service too anyway. If you use batteries for backup, it will take a lot of them to work through a rainy day. It's not going to be cheap...or small, a 50 watt solar panel is about 6 square feet

The generator is an attractive economic choice, short term. What about a natural gas fuel cell? They are said to be quiet, how's the price of natural gas locally?

If you can reduce the electrical demand in the shop, solar could be a reasonable option, but you'd probably still want to be tied to the grid for backup power.

If you have not got some of the equipment yet, you could consider gas powered equipment. A gas powered air compressor is pretty easy to come by, as is a gas powered welder (some of which will also function as a generator) and for things like lathes, mills, etc that you don't have yet, what about older line-shaft powered equipment run by a stationary diesel engine?
 
Last edited:
You must log in or register to reply here.
Back
Top