advice on electrical

[Steven Triggs]

I'm trying to decide on how exactly I want to do the electrical system for my new shop. All along, I've been planning to run a 100 amp sub-panel off of my existing 200 amp main panel.

However, I've been starting to wonder if this will work well. I figure at most I might simultaneously use the Dust Collector (18 amps), Compressor (18 amps), Planer (22 amps), lights (4 amps), A/C (15 amps), and Air Cleaner (3 amps). This would draw about 80 amps. Is it likely that my existing 200 amp panel can take a hit for a continuous load of 80 amps and still provide sufficient power to the house. I consider it very feasible that while I'm in the shop, the house would have the Air or Heat on, the water heater could kick in, the dryer could be running, and the oven might be on.

The following are my planned circuits:

planer 30 amp, 240 volt
jointer 20 amp, 240 volt
dust collector 20 amp, 240 volt
table saw 20 amp, 240 volt
compressor 30 amp, 240 volt
band saw 20 amp, 240 volt
car lift 30 amp, 240 volt
A/C 20 amp, 240 volt
drill press 15 amp, 120 volt
air cleaner 15 amp, 120 volt
lights 1 15 amp, 120 volt
lights 2 15 amp, 120 volt
gen. recept. 1 20 amp, 120 volt
gen. recept. 2 20 amp, 120 volt

I was considering adding a second meter, but my local building department said "no go" on adding a second meter to the same building (workshop is attached). That said, my only option for getting larger capacity would be to replace my meter, and that is really going further than I want to both in terms of cost and hassle.

Anyway, please let me know your thoughts on this.

Thanks.

[Randy Denby]

Steven, you are right on with your reasoning. But, it will be very rare for most of your equipment to run anywhere near the rated full load amps. Air compressor and lights will be close, but tablesaw,dust collector ,planer usually run about half and sometimes alot less. Dependent on load.In the case of the dust collector, it will be dependent on how efficient the layout and how many gates are open.
To ease your mind, I've got a similiar setup, and never any problem of tripping.
In my shop, I've got a oneida dust collector, cabinet saw, 15" heavy planer, 16" minimax bandsaw,14 flourescent lights, window unit, 8" jointer, fans. I hardly ever have more than one machine running at once. We do have gas heat in the house..but everything else is electric. How many KW is your electric heat? 15KW pulls 60 amps, 20kw pulls 80 amps.
It might help to have your electrician do a load to ease your mind. Also might make some recommendations. Good luck!
Randy

[Ben Grunow]

Most of the ratings are starting loads so your 200 should be more than enough.

The worst part about a 400A service is the disconnect cabinet that goes on the outside of the house. It is huge (2' x 4' ish)

[Brad Noble]

>>It might help to have your electrician do a load to ease your mind. Also might make some recommendations.<<

This is VERY GOOD advise. One of my woodworking friends here in my home town is a commercial electrician and I had him come over and do just that in my shop and home. My shop is smaller (16 by 24) and I have Propane heat but I also have a window a/c unit. Tools are similar, lights too. He gave me the "all systems clear, full steam ahead" signal when he finished. The others are correct, you will likely never have all those tools running at the same time.

Good Luck.

Brad

[Ryan Myers]

From an electricians stand point, the 100A will be more than suffecient for the amount of equipment you going to be operating. As others stated, the likelyhood of everything running at one time is very limited. Still you can run your service beyond 80% of the full 100A capacity as long as it isn't continous. Continous is defined as three or more hours.

Another choice would be to upgrade your meter to a combination meter/disconnect with a 200 main and two sets of take offs. Then you could have 200 amps running to your house and 200 to your shop. You would still have a 200 amp max total capacity for both house and shop.

[Rob Will]

If you are a one person shop.......don't worry about it. Odds are you'll never overload the panel.

Around here if you add up all the fans, compressors, augers and stationary power tools, you get about 200 hp. On top of that, there is lighting for two shops AND all the usual stuff for a fairly good size house.

Obviously all of this stuff can not run at the same time but we generally don't have to think about it. It all goes through one 200 amp 3 ph service with a 200 amp fused disconnect. The power company set up a recorder here for a few days. The highest measured current was about 167 amps.

Just make sure everything is correctly fused, all wire is of adequate size, and all the connections are tight. I personally like panels with copper buss bars, less chance of corrosion and heat problems. And as Ryan pointed out, a 200A feed-through meter base / lug panel with a 100A take off is a good way to move the load off of the inside panel all together.

Rob

[John Bush]

Hi Steven,
Same advice here. My shop is 150 ft from the house and I was able to "share" 125 amps from the main 200 amp panel. I have simlar equipment with the addition of a 175 amp mig. You should have no problems at all with you design. JCB.