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Forum topic by Floyd Hall posted 06-18-2018 01:19 AM 1003 views 0 times favorited 29 replies Add to Favorites Watch
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Floyd Hall

124 posts in 449 days


06-18-2018 01:19 AM

Topic tags/keywords: question

Hi folks,

As I’ve noted elsewhere here, I am in the process of trying to by a big 16 radial arm saw. An electrician finally came out and said I would need a new box (I have two boxes, one for the house and a separate panel for the shop. I am talking about the latter).

The box I’m talking about serves several outbuildings and has about 100 amps. Of that only about 35-40 amps is allocated for the shop. There is one 20 amp 110v circuit for everything except the table saw which has a dedicated 20 amp 220v circuit dedicated. But besides the radial arm saw, which draws a lot of amps on startup and needs at least a 35 amp 220v circuit, I’m also looking at a big 3 hp bandsaw and a 15i planer down the road. I am a one-man shop and I don’t envision hiring anyone down the road.

Right now I’m looking at a 200 amp box. Any recommendations?

Floyd


29 replies so far

View JCamp's profile

JCamp

850 posts in 728 days


#1 posted 06-18-2018 02:08 AM

I like GE boxes. I think they make some that have 40 spaces? And buy all new breakers cause there’s a chance that your old breakers from your old box won’t fit in the new one…
Also go thro and see if you want anymore outlets or lights anywhere. This would b the best time to go a head and install them

-- Whatsoever thy hand findeth to do, do it with all thy might

View therealSteveN's profile

therealSteveN

1593 posts in 752 days


#2 posted 06-18-2018 02:08 AM

I have a Cab saw, 8” Jointer, 15” planer, drill press, 3 router tables, 2 dust collectors, 2 chop saws, a huge assortment of 110 hand held tools, and I have a 100Amp line going from the house to the barn. Where I am in SW Ohio it’s all been ok’d by code, and we are pretty strict compared to many places. Ohh also have a welder running 50 amps by itself.

I am generally a one Man shop. I frequently have a person in for purposes of me teach, they learn, but seldom do I let them run tools while I am also running something.

Point is, there are never more than 1 of any of these tools going at once, with exception of a tool, and it’s DC. No brown outs, no faults, insurance guy is ok as long as code is ok, which it is. House is 157 feet from the panel in the garage, to the panel in the barn. I have #1/0-1/0-1/0-4 aluminum line making the run. Alls good.

We have VERY rocky soil, and digging the required 30” deep trench was a royal PIA, never wanting to do that again I threw $$$$$ at it, and we put the burial cable into a 2” diameter conduit. I can fish cable, security line, or pretty much anything without having to dig again.

What are you running from to the barn/shop? House, or a dedicated line? I would be more concerned about the distance, versus the size wire you are running. Voltage drop is a real thing, and finding out too late you can’t run your tools, you’ll wish you had spent the money from the start on big wire. A lot of home centers wanna sell you #8 or some crazy stuff like that.

Has the electrician run a load calculation for you? I’d ask him about the 200 amp, he may have a good reason for it, but wire size, and having adequate circuits for your intended use, PLUS code requirement are what will drive what you need.

-- Think safe, be safe

View Floyd Hall's profile

Floyd Hall

124 posts in 449 days


#3 posted 06-18-2018 02:41 AM


I have a Cab saw, 8” Jointer, 15” planer, drill press, 3 router tables, 2 dust collectors, 2 chop saws, a huge assortment of 110 hand held tools, and I have a 100Amp line going from the house to the barn. Where I am in SW Ohio it s all been ok d by code, and we are pretty strict compared to many places. Ohh also have a welder running 50 amps by itself.

I am generally a one Man shop. I frequently have a person in for purposes of me teach, they learn, but seldom do I let them run tools while I am also running something.

What are you running from to the barn/shop? House, or a dedicated line? I would be more concerned about the distance, versus the size wire you are running. Voltage drop is a real thing, and finding out too late you can t run your tools, you ll wish you had spent the money from the start on big wire. A lot of home centers wanna sell you #8 or some crazy stuff like that.

Has the electrician run a load calculation for you? I d ask him about the 200 amp, he may have a good reason for it, but wire size, and having adequate circuits for your intended use, PLUS code requirement are what will drive what you need.

I have several outbuildings and was considering moving out into them at some point. But in all likelihood, I’ll probably just stay where I am in the basement. It’s a nice space. Plus the outbuilding would require extensive work. I would have to be doing very well to justify the expense. Anyway, I checked the box just the other side of the wall from the shop and it has 125 amps, all being used. About 40 of that now goes to the shop. So I’m thinking maybe a 250 amp box would do the trick. That would give me enough power for the shop and enough to extend or expand power to the outbuildings. Currently, two of them—both storage barns—are on a single 20 amp circuit. There are two other buildings without service that might need it some day.

View msinc's profile

msinc

566 posts in 681 days


#4 posted 06-18-2018 12:37 PM

When you say “need a new box” I think the electrician means you need another service. It sounds like you have a 100 amp sub panel being fed off your house service. How big is the service running to your house? They are typically 200 amp. If so, you cant sub feed 200 amps from a 200 amp existing panel. If this is the case then you need a new service and a panel and I would keep what you have running what is existing and have the new 200 amp panel just for the shop. I have 200 amp service with 40 breakers to my 30 X 30 shop and I don’t have a lot of space left in the panel. It is nice to have a few slots left empty for possible future machines.
The main thing to watch out for with a new panel is not so much who makes it, they are all UL listed and NEC certified {which means there really are no bad ones}, but whether or not you can easily get breakers to work in the panel in your area. I have a Square D panel in my house….no one sells Square D breakers around here, I have to order them when needed and that is a pain.

View rwe2156's profile

rwe2156

3140 posts in 1659 days


#5 posted 06-18-2018 01:52 PM

200A would require a separate service install which would be quite expensive.

Sounds like he is talking about changing your existing sub panel so it will hold more breakers.

100A is plenty of power for a shop like yours.

-- Everything is a prototype thats why its one of a kind!!

View Holt's profile

Holt

277 posts in 2807 days


#6 posted 06-18-2018 02:21 PM

Whenever possible, I buy and deploy Square D QO boxes and breakers. The one time I had to use a GE product, the bolt on flange had a different hole pattern than everyone else and I ended up having to order the party and wait 4 days for it. I guess if your supplier had a good stock of all the GE stuff that goes with the box, then they would be fine, I had no gripes on how well it was made.

-- ...Specialization is for insects.

View Fred Hargis's profile

Fred Hargis

5143 posts in 2671 days


#7 posted 06-18-2018 03:46 PM

Square is the most common around here, and would be my choice. It’s also the easiest to find the needed breakers. But I admit, I think you have misinterpreted what the electrician said…..but you’ll get it figured out.

-- Our village hasn't lost it's idiot, he was elected to congress.

View Floyd Hall's profile

Floyd Hall

124 posts in 449 days


#8 posted 06-18-2018 05:37 PM

I’m just sorting this all out. The guy who built the house was an electrical engineer and just kind of did things his way, plus there have been a couple changes to the configuration.

Anyway, there are two boxes:

1) The big box that serves the whole house and is mounted in a storage room on the opposite side of the house, about 35 feet away. It has circuits totaling 780 amps, though about 70 amps worth of space is disconnected or unused.

2) The little box is on the outside wall just on the other side of the shop a few feet away. It has space for 125 amps and they are all being used. This one serves the shop, several outbuildings, the AC, furnace and a couple other things. This is the box I was going to upgrade. I was told by one electrician that it connects directly to the meter, which is mounted right next to it on the outside wall.

Sorry, I am not a electrician. Just trying to figure out what I have and what to do with it.

View Fred Hargis's profile

Fred Hargis

5143 posts in 2671 days


#9 posted 06-18-2018 07:15 PM

Adding up the amps of the breakers doesn’t give you any useful information. The easiest way to see the total capacity of the box is to look at the main disconnect breaker, it will be 200 amps, or 100 amps, or something like that. The one that is topmost/center (usually) in the panel. If the second panel is connected directly to the meter, and it needs upgrading, you may be in luck. It may be as simple as replacing the panel (and the feeder, maybe) and if that’s the case I’m back to suggesting you go with a square D panel….though it may save you money to buy the same brand you have, them you could reuse the breakers in the old one.

-- Our village hasn't lost it's idiot, he was elected to congress.

View CaptainKlutz's profile

CaptainKlutz

535 posts in 1672 days


#10 posted 06-18-2018 10:41 PM

hmm..
We electrical engineers can be really sneaky. We will spend weeks reading NEC & local code books, making calculations, negotiating variances with inspectors; all to save a couple bucks. SO making changes to an existing power system can become nightmare very quickly. Suggest you contact more than 1 electrician for a quote and have them run total load calculations.

+1 => Agree with others, not enough information to make clear recommendations.
If your electrician is suggesting installation of 200A rated panel to get more circuit space on existing 100A sub panel circuit, that is a viable solution.

Note that if you make any changes to existing panel(s), inspector can require that entire panel meet current code requirements! Electrical codes changed dramatically in last 10 years. Example – in some areas updating an old panel might force an update to use all ARC fault breakers with are 5x cost of old fashion type. Another change was requirement that all circuits 20A below in ‘wet’ environment have GFI protection. Many localities are requiring GFI even on 240VAC circuits of 20A or less in Garage/Basement, or if wires run under ground. 10+ years ago GFI/ARC fault breakers had lessor requirements.

FWIW – Adding up total protection level tells us little, except 780A protected circuits in a 200A box has a very high probability of exceeding the mfg load balancing limits on internal bus bars (which is usually 2x-2.5x panel rating per bus). Many inspectors can/will overlook panel ratings, but are only supposed to ignore it if actual loads are less than breaker ratings. Need load analysis to know if previous owner engineered a problem.

Best Luck..

-- I'm an engineer not a woodworker, but I can randomly find useful tools and furniture inside a pile of lumber!

View Floyd Hall's profile

Floyd Hall

124 posts in 449 days


#11 posted 06-19-2018 12:48 AM



Adding up the amps of the breakers doesn t give you any useful information. The easiest way to see the total capacity of the box is to look at the main disconnect breaker, it will be 200 amps, or 100 amps, or something like that. The one that is topmost/center (usually) in the panel. If the second panel is connected directly to the meter, and it needs upgrading, you may be in luck. It may be as simple as replacing the panel (and the feeder, maybe) and if that s the case I m back to suggesting you go with a square D panel….though it may save you money to buy the same brand you have, them you could reuse the breakers in the old one.

- Fred Hargis

Well, I want this done right, so if it’s a little bit extra to do that, we’re good.

View Floyd Hall's profile

Floyd Hall

124 posts in 449 days


#12 posted 06-19-2018 01:02 AM


..

+1 => Agree with others, not enough information to make clear recommendations.
If your electrician is suggesting installation of 200A rated panel to get more circuit space on existing 100A sub panel circuit, that is a viable solution.

FWIW – Adding up total protection level tells us little, except 780A protected circuits in a 200A box has a very high probability of exceeding the mfg load balancing limits on internal bus bars (which is usually 2x-2.5x panel rating per bus). Many inspectors can/will overlook panel ratings, but are only supposed to ignore it if actual loads are less than breaker ratings. Need load analysis to know if previous owner engineered a problem.

Best Luck..

- CaptainKlutz

Like I said, we’re sorting things out, but we’ve solved several problems already and the end is in sight.

The big question right now is what I need box-wise to properly wire a low end commercial shop. Except for the table saw, which is on a dedicated 20 amp circuit at 220v, the rest of the shop runs off a 20 amp circuit at 110v. This includes a full-scale drill press, a smallish 14i Rikon bandsaw, a older 10i Milwaukee chop saw, a 12i Delta lunchbox planer and a decent short-bed 3/4 hp 6i jointer. The saw I’m looking at—a 16i 5 hp DeWalt—would need 35-40 amps. Plus I will almost certainly upgrade the bandsaw, jointer and planer. For these alone I am guessing I need 100 amps of service. However, I also need perhaps another 60-80 amps to go to the outbuildings, one of which might eventually become my shop. At that point, I might consider 3-phase tools. But right now I just want to get the shop wired right.

View sawdustdad's profile

sawdustdad

366 posts in 1063 days


#13 posted 06-19-2018 01:08 AM

Sometimes it’s easier to get the electric utility to put another meter on your shop and set up another service. Around here, if the usage is sufficient, they do it for free. My shop has its own 200A service and meter.

-- Murphy's Carpentry Corollary #3: Half of all boards cut to a specific length will be too short.

View BlasterStumps's profile

BlasterStumps

942 posts in 617 days


#14 posted 06-19-2018 03:20 AM

+1 with Captainklutz post. Spot on.

Mike

-- "I build for function first, looks second. Most times I never get around to looks." - Mike, western Colorado

View Holt's profile

Holt

277 posts in 2807 days


#15 posted 06-19-2018 12:41 PM

Depending on your state and power company, you may be able to get some financial assistance toward setting up solar panels and be able to sell power back to the power company. Assuming your shop isn’t in use drawing lots of power all the time, you might make enough off selling power back to the electric company to cover the minimum monthly charge for the new service. That’s my plan for my new shop. Since I have a day job, I could have five days a week where all the power generated sells back to the electric company…

-- ...Specialization is for insects.

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