Electrical question

Since Ned's Woodshop is about to set sail, it is time for assessing the electrical situation.

I plead near total ignorance as to the Capacity of the house electrical system. To my untrained eye, it looks like I'll be getting separate service for the shop. what do you experts think?




the house is a modular trucked in and assembled just about 20 years ago.

the overall view of the panel is cut off just a bit, but that last space below the blue breaker is it, no more space beyond that.

the Range is a curiosity, because we have gas for cooking, hot water and clothes drier. I am going to build the shop using extension cords from the utility room, but obviously I'll need to do some upgrading in a hurry once I have the structure up and dried in.

No problem Mahn!

Just add another larger breaker and run a large wire out to the shop. Well have your electrician do that. Then install a subpanel out in the shop. All you need is two spaces free and you have that. You could probably use the space for the range probably, but you have plenty of space.

I installed a 100 amp breaker and subpanel in the lab from my main panel. It's overkill but now that I am going with RPC I am glad I did. Start up load on the RPC could be 60 - 80 amps. But I would guess 60 amps would be plenty for your shop.

really? that's all it will take? (all he says... laughing on the verge of nervousness) trench a conduit 130' and put in a second panel? won't I be taxing the service if I do that? I'll need 220 out there, won't that draw too much from the house?

Yup, thats about it. (laughs at how easy that is say compared to actually doing it)

No you won't tax it. The only load is when something is actually running and your not going to pull that much of a load with any typical tools.

Check with you power company of course. Their rules may vary. We can't (Legally) run power to an outbuilding. It has to be separate service and then they charge commercial rates on that service!!

Ned,

You have enough room for a 220V Breaker. You could probably run a 60amp breaker. I am not sure of the wire size you will need. This can get expensive.

Then out in the shop install a small box which would give you enought for a 220v breaker and several 110v breakers.

You big expense will be the cost of the 130' of wire from the house to the shop.

Some one else needs to step in here about the 60 amp 220v and what wire size.

Since you are using gas for as many things as you say then I think you have plenty of capcity for a breaker out to the shop.

how do you heat ?? Electric ?

here's my 'plan'.

quick and dirty tonight: 110 outlets along each wall 4' apart 50" up from the floor.

that works out to three on each long wall, one on either side of the door and two on the far wall, plus two up in the loft.

Add a couple near my benches on the north wall, plug mold for small tool usage and a charging center near the storage cabinet for cordless tool charging etc... (three varieties at the present moment)

220: 6 or 7 outlets: one for the TS, one for the bandsaw, DC and compressor plus one extra on the end wall in case I move things around (works out to two on each long wall, located roughly near the center of the shop). Possibly one in the center of the floor, or a ceiling drop, not sure yet. The DC will be out in the 'bumpout' where I'm going to scale down Marty's chip separator and bin and compressor space, so one outlet out there, but under cover. (enclosed lean to against the outer wall).

Lighting, I'll have two 8' under the loft, two mounted up near the ceiling in the full height area. One ceiling fan w/ lights in the tall area, a couple of incadescent fixtures under the loft. two sets of task lights above the bench area. (making this up as I go, but I've tried to 'take notes' when others build their shops)

AC... going to go with a midrange wall unit, someday.
Heat... i'll get back to you on that one this fall.

still think that'll work on that sub panel? I realize I won't ever turn 'everything' on, but lights plus one or two tools plus DC at one time would happen on a regular basis.

Bartee Lamar said:

Ned,

You have enough room for a 220V Breaker. You could probably run a 60amp breaker. I am not sure of the wire size you will need. This can get expensive.

Then out in the shop install a small box which would give you enought for a 220v breaker and several 110v breakers.

You big expense will be the cost of the 130' of wire from the house to the shop.

Some one else needs to step in here about the 60 amp 220v and what wire size.

Since you are using gas for as many things as you say then I think you have plenty of capcity for a breaker out to the shop.

how do you heat ?? Electric ?

Click to expand...

Oh trust me the electrical to the shop is a large factor of the budget, though one that will come 'down the road' I'm going to rough it for a few weeks with just 'construction' mode (extension cord until budget recovers)

As for heat, in the house, forced air, gas fired furnace. Shop... TBD at a later date. Might just shiver the first winter. BTDT got the t-shirt.

Ned Bulken said:

here's my 'plan'.
...
AC... going to go with a midrange wall unit, someday.
Heat... i'll get back to you on that one this fall.

still think that'll work on that sub panel? I realize I won't ever turn 'everything' on, but lights plus one or two tools plus DC at one time would happen on a regular basis.

Click to expand...

Ned,

(Not an electrician, just a well-read handyman...)

If your stove, dryer, Furnace and HWH are all gas, then your house really does not have a large electric load on it. The biggest load, I think, would be your A/C in the summer time. Other than that, your fridge will be a modest constant drain, not sure what else.

I can't tell, how large is the main breaker on the house? I'm betting it is at minimum 100a. I don't know the formula off the top of my head but you can figure out the amp draw for the A/C, fridge, freezer, and add some cushion, and you'll have a pretty good idea of the amp-load that your house uses. This'll tell you if you have "room" for a 60amp breaker to feed the shop.

As for the "still think that'll work on the sub-panel"... Ned, the physical size of your sub-panel will determine how many breakers you can cram into it. The amp rating of your sub-panel main breaker, on the other hand, will determine how many amps you can run at once. The two are not necessarily connected, AFAIK.

In the shop, at any one time you'd have a main tool on (ie: TS) as well as the DC, and possibly the A/C unit. figure out their amps, add it up, and you'll know if a 60amp sub-panel will do the trick. I think it will.

Ned,

I won't comment on your ability to run your shop from one breaker off that subpanel...since I'm from the school of over-kill when it comes to electrical. I will, however, advise you to carefully think through what will typically be on at the same time. Do the math...figure out the actual current draw from your list of what'll be running...and go from there.

If possible, make the outlets on the walls come from different breakers, to allow you to power more than one breaker's worth from them.

I also add a word of advise on you plans "for the time being". Running an 'extension cord' for 130' to power tools is going to be HARD on your tools...even if you do what I did...run that 100'+ extension cord as 12/2 Romex. It's going to shorten the life of anything you run for any length of time. There's no getting around that...the drop across that much wire WILL adversly affect your tools! So keep that in mind as you plan how long the "for the time being" stage will last...and use tools accordingly.

Good luck...and keep planning and asking questions!

- Marty -

Art,
other than the kids leaving lights on, we're running a stand-alone upright freezer, the new fridge, plus various tv's, computers and what not.
AC, we only use window units, small ones, and we only cut the humidity if truth be told.

OK, sounds like electrical will be something that can be done without breaking the bank, so to speak. Just a matter of budget budget and more budget. Thanks for reminding me that it is the load that is the key. I was adding up amps on the breakers and getting way too high a number, since not all of them are running at the same time (normally), we should have capacity to spare for me to run a couple of tools every now and then.

One thing I considered when I was fighting TXU (Texas Electric) on turning on the power to the shop (separate meter, they required it to be on commercial rate, just like Jeff mentioned) was to tap on to the house meter and run a main wire from there to the box in the shop. It would work off the same meter for being charged, but didn't go through the house breaker box and the limitations on power that it could have imposed. Plus it would be easier to tap on the power outside the house instead of having to snake the wire throught the box and house to get outside. I understand that there are special meters that are set up with 2 sets of lugs just for this purpose. I was dreading the trench too because of the tree roots and the sprinkler system (I have no idea where the pipes are. Installed by previous owner.) This was an instance where deregulation helped me because I got a different carrier to do the shop! But they also said they would do both house and shop on residential rates, unlike TXU. Since the shop already had separate service wire from the pole, this was a whole lot easier for me.
I did get my Square D box on ebay, brand new in factory sealed carton, for a lot less than the local box stores. Found some new breakers, and some good quality used ones that have worked out great for me, and saved a bunch there also.
Your journey is just starting. It will be fun, and heart breaking at times, but it is worth the effort. Jim.

Marty Walsh said:

I also add a word of advise on you plans "for the time being". Running an 'extension cord' for 130' to power tools is going to be HARD on your tools...even if you do what I did...run that 100'+ extension cord as 12/2 Romex. It's going to shorten the life of anything you run for any length of time. There's no getting around that...the drop across that much wire WILL adversly affect your tools! So keep that in mind as you plan how long the "for the time being" stage will last...and use tools accordingly.

Click to expand...

With all due respect, its not quite that simple (I bet you know that and I'm just un-doing your effort to keep it simple ). Voltage drop is going to depend on wire size and load. According to the voltage drop table in my pocket ref (real handy for this), at 120V you can draw a full 15 amps on 120 feet of 8 awg wire and still be less than 2% voltage drop. For 20 amps at 120V, you could go 90 feet on 8 awg. Still kinda pricey extension cord! It would pay to measure the actual distance and get just enough wire to make up the right cord rather than buy a pre-made one.

Just for reference Ned. My house has a main panel of 200 amp service. Central heat and air/electric. All the usual electrical stuff in the house. We do cook and heat water with gas. I have a 100 amp breaker in the panel. That feeds a 100 amp panel in my shop. My shop is pretty large and all the usual machines. Never had a single problem.

Before I installed all this I ran it past my buddy, an industrial electrician for many years as well as residential and he said it was more than adequate. He suggested a 60 amp panel in the shop. But I went with the 100 amp so I could have more breakers and divide the circuits up better. It's nice to be able to turn off the half lights while your wiring on the other half. It's safe and your not in the dark. Same with outlets.

Jim brings up a good point about the meter base. But before you do anything you need to talk to you electric company. They can tell you if you can do that, what size wire you need, conduit, etc. Our advice is great, but if you Power Co. doesn't allow it, it's useless. And not to mention your insurance might use it as an exscuse not to pay out in case of claim.

Marty Walsh said:

Ned,

I won't comment on your ability to run your shop from one breaker off that subpanel...since I'm from the school of over-kill when it comes to electrical. I will, however, advise you to carefully think through what will typically be on at the same time. Do the math...figure out the actual current draw from your list of what'll be running...and go from there.

If possible, make the outlets on the walls come from different breakers, to allow you to power more than one breaker's worth from them.

I also add a word of advise on you plans "for the time being". Running an 'extension cord' for 130' to power tools is going to be HARD on your tools...even if you do what I did...run that 100'+ extension cord as 12/2 Romex. It's going to shorten the life of anything you run for any length of time. There's no getting around that...the drop across that much wire WILL adversly affect your tools! So keep that in mind as you plan how long the "for the time being" stage will last...and use tools accordingly.

Good luck...and keep planning and asking questions!

- Marty -

Click to expand...

Marty,
130' is a long estimate of the distance from the main box to the shop. I could cut that even shorter by running the line up the crawl space beneath the house and out a mere 15' to the sub panel.

The near corner of the shop is only 12' from the house, I'll just hang an extension cord out of the bedroom for 'build' power, at Worst 30' to 40' max. And that's to the Far corner of the shop. I won't be stringing power that far, I'll be walking wood or compressed air run nailer that far.

I'll do my best to get the electrical on the short list after making things weather tight. I won't let things go long at all. Besides, I'll just be puttering for at least a month once things are dry, moving tools and benches around etc...

Thank you though for the sage advice. Honestly, I'm not expecting to be fully up and running for at least a month due to a busy summer with work.



see that first window? there's access to the crawlspace right below it, I can run the 'construction' power up and out there and still keep the kid's bedroom bug free.

Ned, when figuring for voltage drop, don't forget to estimate the distance from your house ckt Brkr Box to the outlet in the kid's bedroom, as it should be included in the overall distance from the breaker to the tool, especially since the house wiring to that outlet is most likely only 12 ga wire.
(sorry to add more to the confusion)

Norman Hitt said:

Ned, when figuring for voltage drop, don't forget to estimate the distance from your house ckt Brkr Box to the outlet in the kid's bedroom, as it should be included in the overall distance from the breaker to the tool, especially since the house wiring to that outlet is most likely only 12 ga wire.
(sorry to add more to the confusion)

Click to expand...

SO, we're back to square one.

still doesn't change much, I've got power 15' from the proposed shop site, which I'll be stringing an extension cord from. I'm going to have some voltage drop no matter what I do. Ultimately my CMS and a compressor will be the only tools affected until the sub panel is put in.

ned, on the wiring of your shop.........have you done any wiring before? do you understand basic electrical theory?.....if the answer to either question is no then before you spend a dime learn! it`s not just tools at risk if you screw up it could be property or even lives .......electrical ain`t that hard but it must be done right......tod

as for an extention cord.......buy a 100 ft 10gauge cord (or make one) and plug it into the receptacle closest to the breaker panel.....you`ll be fine running cary-about tools off this...

tod evans said:

ned, on the wiring of your shop.........have you done any wiring before? do you understand basic electrical theory?.....if the answer to either question is no then before you spend a dime learn! it`s not just tools at risk if you screw up it could be property or even lives .......electrical ain`t that hard but it must be done right......tod

Click to expand...

I'll be calling in a pro for the actually wiring. Hence the budget crunch. one of my Lodge brothers has an electrical contracting business, I'm going to tap him for the job, he'll send a tech out and that will be that.
Thanks for the tip on the heavy duty extension cord. the 'far' window is the laundry/utility room, and that's about as close as I can get, so at worst... 80' or so.

gotta dash to work. cyas!

glad you`re consulting with a pro ned! now for saving money ....once he lets you know wire size you should be able to run the service cable and in the process save a few hundred labor bucks..in fact if this guy is a buddy he may be cool with letting you actually run the wires and just pay for a tech(`lectrition) to actually hook them to the panels? that way you`ll learn and save money while being safe to boot.....tod