wiring questions

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Forum topic by TheSteve posted 02-13-2008 06:41 AM 1612 views 0 times favorited 10 replies Add to Favorites Watch
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34 posts in 4269 days

02-13-2008 06:41 AM

ok, here’s my situation. we have the main line going from road to house, that breaks into a sub pannel, that then breaks into the shops sub pannel. this is fed by a 6/2 cable on a 80 amp breaker… best i can guess is the shop is only getting around 40 watts… this feeds lights and recepticles… the pannel box is very old and the wires arent great either.. ( is a house trailor turned into a shop, got the trailor for free + haul bill) when you start up any machine the lights dim, and on some ( planer, jointer, even sometimes ROS ) you can tell the power fluctuates… this is not good for trying to get quality out of your tools or the life of them either ( 1 planer motor already burnt up) i have to convince my fiance’s dad to let me put a sepperate utility pole to feed the shop… anyone have any up to date pricing on this? i can get the pole easy, need pannels and wire im guessing, what size would you go on outlets? i want to get atleast 2 220’s for future expansion in tools. how much does a stand alone shops ( small ) electric bill usually run? and since its a house trailor with inspection sticker do you think it will have to pass code again?

we live in tennessee

i still gotta find a way to convience him, ill pay cost and electric bill …. lol

thanks for any help,


-- Aint nothin to it but to do it!

10 replies so far

View Joey's profile


276 posts in 4326 days

#1 posted 02-13-2008 03:25 PM

First off, it’s not wattage. It’s amperage. 40 watts would run one small light bulb. Trailers are notorious for using cheap wiring. If it was built back in the 80’s I would guess that it has aluminum wiring. Aluminum is ok but it can’t handle the load that copper can. It tends to overheat under a heavy load. It sounds like you’re going to have to completely rewire. I would have at least 100 amps going to the shop. Once you get to the sub panel, you’ll need separate circuits for machinery. The planer, and jointer are going to pull alot of power. Look at the book on each and it will tell you how many amps it pulls. This will let you know how many breakers you need. if it pulls 10 amps, you can use a 20 amp breaker which is fine on a 110 circuit. If you have a tool that can be converted to 220, and the panel and wiring can handle it, (you’ll need at least 10 gauge and i would go with 8), do it. you’ll have more power to the tool and better results. but i would diffenately rewire the trailer.
Unless you’re running the machinery all day long, i’ve found that it doesn’t affect the bill much, couple dollars. I run a table saw, band saw, oscillating sander, dust collection, jointer and planer. i only use my shop for a few hours a week, so I don’t see much of an increase.

-- Joey, Magee, Ms

View Peter Oxley's profile

Peter Oxley

1426 posts in 4385 days

#2 posted 02-13-2008 03:59 PM

Yeah, you probably should rewire everything. In most areas you are required to get a permit and an inspection when you do anything major to the wiring, so I imagine you will have to deal with that. I’d use 12 ga wire for all your 110 circuits so you can use 20 amp breakers.

Most of my electric bill is heating. I pay about $30 a month when I’m not heating, and about $200 when it’s really cold.

-- -- --

View Mario's profile


902 posts in 4562 days

#3 posted 02-13-2008 04:54 PM

I agree with both of the other posters so far. I have my shop power going through the home also but have an 80 Amp service to the shop and looked into having it come directly into the shop but the price would have been over 3K so I have not done that. My shop was anly partially wired and it is now all 12ga copper.

-- Hope Never fails

View TheSteve's profile


34 posts in 4269 days

#4 posted 02-13-2008 06:06 PM

thanks for your responses, i meant amps instead of watts i edited twice but for some reason wouldnt save =( ... i dont think he will go for rewiring right now and doesnt want an inspector all up in his business so im gonna try to run a dedicated 30 amp breaker to an outlet in the main shop room with 10ga copper for planer/jointer… best solution i can come up with. hopefully this will help.

-- Aint nothin to it but to do it!

View Teri's profile


88 posts in 4273 days

#5 posted 02-13-2008 06:29 PM

I’m just wrapping up the wiring on my shop. I put in a 100 amp service panel. I had electricians recommend a 60 amp panel, but I believe that would be too small, especially when you consider the heating of the building. Here is what I did for outlets: 15 amp (14-2 wire) outlets for lights, and lightweight powertools (sander, jigsaw, etc.). 20 amp (12-2 wire) runs everything else, except tablesaw and radial armsaw. I have a dedicated circuit for each of those, 30 amp (10-2 wire). I will say too, that if you have the option to wire in new outlets, I placed outlets every 3 feet, and in some cases a couple are every 2 feet. A few friends thought it was overkill, but I love it. I don’t even consider using extension cords anymore :)

-- Teri, Kokomo, IN

View jeffthewoodwacker's profile


603 posts in 4315 days

#6 posted 02-14-2008 12:29 AM

When I built my shop I went for overkill and put in a 400 amp dedicated service panel. This powers all the HVAC, lights, and power needs for any equipment that I use. I have three different circuits for the outlets which are placed at 48 inch above the floor and every 3 feet around the wall perimeter. Big equipment all have dedicated power including the 220 machines.

-- Those that say it can't be done should not interrupt those who are doing it.

View matter's profile


210 posts in 4280 days

#7 posted 02-15-2008 01:36 AM

Because you are using an old house trailer, it may have had some retro-fits over the years. An 80a should more than do what you need for a small shop. Shop #2 is running off of a 60a sub-panel right now with no issues, that includes the heater which is 220v.

To get around our limited amperage, we have everything on it’s own 15a or 20a circuits. Lights on one, they never dim. Each machine has it’s own circuit too. Total cost to rewire a 24×19 shop- $300

It costs about $120 CAD (or $120.55 USD) a month in hydro to heat/run that shop

-- The only easy wood project is a fire

View Partridge's profile


296 posts in 4467 days

#8 posted 02-15-2008 02:16 AM

I would add breaker to separate light from plugs. If you have 80 amp going into shop it should be fine. is it 110 or 220. if panel do no have any more space the they make breakers that will help this problem. I you use ex cords
make sure it is at lease 2/12.

-- I get out in the shop when I can

View TheSteve's profile


34 posts in 4269 days

#9 posted 02-15-2008 03:55 AM

its a 220 6/2 wire that feeds the shops subpanel. the wire only has a 55 or 60 amp rating, the breaker its on is 80amp thats why i was figuring about 40-50 amps that its drawing. the main problem is, the workshop is the kitchen + living room of the trailor with the wall knocked down and only 1 breaker feeds the whole room. prolly 20-30 amp. i want to run 2 seperate 30 amp outlets with their own breakers to go on opposite sides of the room so those 2 outlets will get as much power as they possibly can. i dont mind moving machines and unpluging. i dont know if this will solve the whole problem, but im pretty sure it would be 100% better. the bummer is… the pannel is on the opposite end of the trailor then the work room ( around 50 ft ) =( ... its my top priority and i wont let myself buy more tools till its fixed which is irritating me! lol … dont wana buy a 500-1k$ planer and burn up the motor…

thanks for all the imput, i appreciate it alot =)

-- Aint nothin to it but to do it!

View DaveH's profile


400 posts in 4289 days

#10 posted 02-19-2008 02:30 AM

Want size main breaker to you have on the trailers panel. If the wire from the house to the trailer is only rated for 60amps you should have a 60amp main on the trailer panel. 60amps will run your shop tools but you will need to re-wire all the plugs. If the the trailer is wired like a house, most of your wall plugs run off the same 15 or 20 amp breaker or fuse on the trailers breaker box. You need to calculate the max load per circuit when wiring.

-- DaveH - Boise, Idaho - “How hard can it be? It's only wood!”

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