Electrical Service - How Much is Enough?
It looks as if my wife and I will be moving into a new house, which would allow me to expand my workshop from its current one-car garage size to an over-sized 2 car garage, and I will be hiring an electrical contractor to bring electrical service to the garage. (We are trying to finalize the purchase of a short sale house that has taken FOREVER, but that's another story!) If we are successful, and it now appears that we will be, I will need to decide if I should get 200 amp service or if a 100 amp will suffice.
Following is a list of the larger stationary tools I either already have or plan on having some day. Of course, not listed, are all the smaller hand held tools and accessories most of us have in our shops. I am not yet aware of the amp requirement for the ductless HVAC I will have installed or that for the overhead lighting.
Any opinions on the size of service I might require for a one man hobby shop? The total here is 158 amps not including the HVAC, the overhead lighting, the air filter, or the portable hand tools.
Thanks.
18" Bandsaw 10a 220v
20" Planer 30a 220v
12" Jointer 18a 220v
Osc Edge Sander 18a 110v
Oneida Cyclone 14.5a 220v
TableSaw 13a 220v
Drill Press 9a 110v
Performax Drum Sander 9a 110v
16" Bandsaw 11.5a 110v
Air Filter ?
Air Compressor 15a 110v
Mitsubishi Split HVAC ?
Lighting ?
Festool Dust Extractor 10a 110v
Rant on Residential Contractors doing Shop Work
I don't respond to posts on posts. But, I can't let this one go.
If you ask a residential electrician what to do, make sure they know they will not get paid if you need to upgrade your service when the in-rush current from your HVAC trips your mains anytime your shop is in use. Seriously, non-shop motor loads will totally wipe out all your shop calculations.
The problem with shops is not FLA (fully loaded amp draw) which is what people on this board talk about day in and day out. It does not matter in shop builds. The problem is in-rush current from low speed (say 1,700 to 3,500 RPM), high torque shop motors. I junked a 7.5 HP 3 phase 208 V air compressor because it pulled 150 A in-rush for 7 seconds every time it kicked. We changed the motor out to a single phase 208 V 5 HP motor frame equivalent and it drew 173 A for 9 seconds. That is not at all uncommon in home shop tools. Anything, I mean anything at all, which is single phase and over 2 HP will have insane in-rush. Please read the reference material I posted.
Electricians without actual industrial motor control experience will not know how to even measure in-rush. Make them show you their test gear. Make them do a 48 hour logging run. If their approach is to read the motor plate (which is how residential electricians are trained), you will be back on this board asking how to upgrade the service.
Residential electricians are not qualified for this job. They know nothing about low speed, high torque motors on shop tools. Your power company (if they work like the three I know well) will do the logging and help project your in-rush. They can size the service based on vastly greater experience. They also get no "bonus" income by coming back to upgrade your service.
One last time, get the largest service you can. Make sure it is a metered main with at least two feeder breakers (one for shop loads, one for the rest). Everything else will get safer and less expensive.
Your local "time and materials" electrician is the last guy I would ask about this problem. This entire line of argument is valid for all residential contractors. They know nothing about shop infrastructure. I speak from experience.
Ok - I will go back to my Grey Goose and FOX news channel. I think Beck is on.