Many new woodworkers ask if they need 240-volt (240V) outlets in their shops.The answer is…It depends.
Having sufficient electrical power is certainly one of the first things you should think about when setting up a woodworking shop.
Unless you are a Neanderthal woodworker who uses only hand tools, your workshop should have plenty of 120V electrical outlets for your tools, lighting, and HVAC systems. Some of those tools, however, may require 240 volts or would operate more efficiently if they operated on the higher voltage.
Some of the things you should consider when evaluating your shop’s electrical needs for 240V circuits are:
- Will my home or shop handle additional circuits or will I have to have a larger electrical panel installed?
- What type of tools and dust collection do you have now or plan to own in the future?
- How do you plan to heat and cool your workshop?
- Do you want hot water in the shop?
My Electrifying Problem
Many older homes built before the 1960s have only 30 amp or 60 amp electrical service. These electrical services terminate in fuse boxes that may contain only two to four 15 amp fuses.
Even homes built after the 1960s may have small electrical panels with 15 amp breakers. These fuse boxes and small electrical panels mean you may have to have a larger modern panel installed before you can add 240V outlets.
I first began woodworking in a detached, single-car garage with an asphalt floor that was built in the 1930s. The only electricity at first was a single 120V circuit to power the garage door opener and an exterior security light. To get at least some power in my shop I hired an electrician to run another single 30 amp circuit to the garage. I could then run one tool at a time and have a couple of fluorescent lights on at night.
I was still limited on power, though, as turning on another tool before switching off the first resulted in a trip to my home’s cellar to reset the tripped breaker. I should have had a sub-panel installed in the shop so I could reset the breaker there.
A few years later, I built a dedicated shop at my new home and made sure to future proof the shop for electrical needs. I had lots of 120V outlets installed as well as multiple 240V outlets on almost every wall. I even had a 240V outlet installed on my shop floor where I planned to put my table saw.
I may have gone overboard but my experience with my first shop taught me having plenty of electricity is powerful!
Advantages of 240V vs. 120V
A major advantage of having 240V is that tools running on 240V draw half the current they would require if operating on 120V. Higher amps result in a hotter running motor, and excessive heat is one of a motor’s worst enemies as it will have a shorter lifespan. By running the tool on 240V, the motor will run cooler and last longer.
Another advantage of 240V is that the size, or gauge, of the electric wiring can be smaller, which will cost less in terms of materials.
Determine if Your Tools Require or Will Operate More Efficiently on 240V
One of the first things to do if you think you may want to have 240V outlets installed is to determine the voltage requirements for your existing power tools or those you may want to add to your tool collection.
If a tool requires 240V, it will have a special plug on the electrical cord. If this is the case, there’s no way around it – You will need 240 volts of juice to use the tool.
You should also determine your tools’ power needs, which are stated in amps. Metal information plates attached to tools or motor housings tell how many amps a tool will require when it’s under a full load.
An example of a full load might be when you’re ripping a two-inch thick piece of oak on your table saw. If the electrical circuit the saw is on is not sized properly and the saw bogs down, the breaker could trip. You may even damage the motor.
Here’s an example of an information plate attached to the body of a Powermatic 230V jointer.
Another factor to consider when sizing electrical needs is that electrical codes do not allow the total load on a circuit to be more than 80% of its amperage rating. If a tool’s amps rating is more than that amount, a new circuit breaker or larger sized wiring may need to be installed. If you are going to have to run a new circuit and the motor can be rewired for 240V, it might make more sense to make that new circuit 240V instead of 120V.
Amp Requirements for Common Power Tool Horsepower Ratings
|Tool Example||Horsepower (HP)||110V Motor||220V Moter|
|Benchtop drill press||1/2||10||NA|
|Cabinet table saw||3||34||17|
Power Requirements of Portable vs. Stationary Power Tools
Small, portable power tools that run on 120 volts usually draw two to eight amps, so a 15 amp, 120V circuit would be sufficient. Larger, stationary power tools like table saws, jointers, and dust collectors might pull 18 or more amps. Be ready for a circuit breaker to pop if you try running a tool like this on a 20 amp circuit!
Other Shop Electrical Requirements
Some considerations in addition to the electrical requirements of your tools are whether you plan to have hot water and to heat or cool your shop. Water heaters and HVAC units typically require dedicated 240V circuits, which cannot be shared with any other appliances or tools.
Higher Volts, Lower Electric Bill?
Some people think because tools running on 240V use half the amps that 120V tools do will result in a lower electric bill. However, that is not the case as the number of watts used remains the same. Your electric bill is calculated on the amount of electrical wattage used, not amps. Therefore, although there are plenty of benefits to having 240 volts in the shop, reducing your electric bills is not one of them.
How Do I Wire My Shop for 240V Power?
Unless you are an electrician, run, don’t walk, away from the idea that you will rewire your shop! It should go without saying that improperly installed electrical systems can maim, kill and cause fires that burn down shops and homes. That’s why you should find a licensed and insured electrician to install any additional outlets in your woodshop. Installing electrical circuits require not only the know-how to do it but also entail in most areas obtaining a permit and electrical inspections. Doing electrical work without permits or inpsections may result in big fines and having to tear out the new wiring.
An electrician will know how to safely add an electrical panel, if needed, and run the wiring to the outlet boxes. If your shop has wood framed walls and ceilings, it’s likely the electrician will be able to fish new electrical wiring through them without causing too much collateral damage to your walls or ceilings. If you have a masonry block shop or no accessibility inside framed walls, the electrician can run the new circuits in conduit or wire mold, which attaches to the surface of the walls rather than running behind them.
Please be aware that adding more or larger circuits to your woodworking shop may require a larger electrical panel, such as a 100 or 200 amp service. So be sure to ask the electrician about that potential cost up front. Otherwise, you may get a shocking bill at the end of the job!