You’re a woodworking enthusiast. You know wood, and you know how to create works of beauty as well as of practical application and everyday use. And, you’re in the midst of creating your ideal woodworking shop, perhaps in the basement or in the garage.
But wood knowledge is not enough in the creation of your dream workshop. A fundamental understanding of electricity is necessary to feed your power tools the energy they need to work at peak performance. Amps, watts, volts, extension cords, and such all have to do with that energy, along with the requirements of the power tools your shop will have.
Let’s look at the energy needs of table saws and the electrical service required for optimal performance.
Watts, Amps, and Volts
- A watt is a measure of power. The rate at which work is done when one ampere (amp) flows through an electrical potential difference of 1 volt is a watt.
- A volt is the potential for electrical energy to move. It’s like water pressure, if you will, or water flowing through pipes. Volts are the measurement of the force that sends electrons (thus, the word electricity) through a circuit.
- An amp, or ampere, refers to the measurement of that electrical current. And current refers to the number of electrons flowing through a circuit. One amp is equal to 120 watts at 110 volts; one amp equals 240 watts at 240 volts.
Do you need to understand all of this? Will there be a test? No, and no. But you must be aware of the need to provide your table saw with the energy it will need to do what you want it to do and do it well.
The table saw’s horsepower will determine how hungry it will be at starting time and cutting time. Its power source and electrical service must be able to provide that energy safely and continuously during operation.
How Many Watts Does a Table Saw Use?
In a way, that is a trick question. The answer to it is when? This is so because your table saw requires higher wattage to start than it does to run, and the higher wattage needed to start the table determines the saw’s horsepower.
If you have an ordinary table saw, nothing really big will require about as much power as your washing machine. But, higher horsepower motors in table saws will require much more.
When assessing the power needs of a table saw, you also have to consider its need for more power at startup than it needs to run after starting. For instance, a table saw requiring 1,800 watts to run efficiently will require over 4,500 watts on startup.
The typical table saw in a hobbyist woodworker’s shop is about 2 hp and will need about 1,725 watts to run smoothly. Running smoothly also has to do with how you attempt to use it.
A 2 hp motor in your table saw can handle cutting a 2” thickness, but the motor will be taxed too much to cut something larger. If your projects will use stock that thickness – up the hp of the table saw you buy. Your table saw blade will thank you.
Can I run a 15 amp saw on a 15 amp circuit?
This is a website about woodworking. While power considerations are an integral part of a fully and properly functioning woodworking shop, we won’t get too much more technical – only a little bit.
Part of the electrical service for your shop, as for your house, is an electrical panel. That panel is the hub of the service, the place where all electrical current flows. In that panel are circuit breakers that will trip if your table saw calls for more amps. While the wire of your electrical service may be able to handle the table saw’s call, and the same for your extension cord connecting the table saw to the service, the amp breaker will trip.
This brings us to the actual amperage moved through the service to your table saw. A wire rated to carry 15 amps can carry 15 amps all day long. But, 15 amp breakers and fuses can carry only 12 amps on a continuous basis. Prolonged use of your 15 amp table saw, then, will trip the breaker and fuse. Circuit overload is the most common cause of tripping breakers and fuses.
Running only one power tool at a time can help prevent tripping. But, the long-term solution is to have an electrician update the shop’s wiring to add separate circuits and connect the different power tools in your shop to their own circuit.
For instance, if you run your dust collector at the same time as you are using your table saw, each should run on its circuit. This will not tax the breakers and fuses, and you will avoid tripping them in the middle of a cut.
Perhaps you are trying to decide between a 13 amp vs. 15 amp table saw and wondering if your 15 amp breaker and fuse can handle a 13 amp table saw. The answer is, like the question, perhaps. Again, breakers and fuses can carry only 12 to 12.5 amps on a continuous basis and only on a dedicated circuit.
So, assuming that dedicated circuit and short bursts of cuts, you should have no problem rather than an afternoon of ripping board length. The difference in price between a 13 amp table saw, and a 15 amp table saw is not substantial, and for the serious hobbyist, those few dollars are worth it, considering everything else we have discussed so far.
15 amp vs 20 amp breaker
Wiring and plugs are the answer to this question. 20 amp plugs will not fit into 15 amp outlets and require different wiring.
A 15 amp electrical circuit uses 14-gauge wire and is served by a 15 amp breaker; a 20-amp circuit will be served by 10 – gauge or 12 – gauge wiring.
They are not interchangeable. Your electrician can advise on the needs of multiple circuits, and you may find that a number of 15 amp circuits will be sufficient for your shop needs and the use of your power tools, including a table saw.
A Few Words About Extension Cords
Extension cords are rated based upon the electrical energy they are intended to carry and the distance they are required to carry it. As extension cords get longer, the capacity to carry current is reduced.
A 12-gauge extension cord should serve you adequately for your hobbyist workshop needs. It will work with a 15 amp table saw, the most likely one in your workshop, and deliver the required current.
But, if your cord has to be longer than 50 feet, you should consider a 10-gauge, as it will deliver power more efficiently to your table saw.
As promised, there is no test on the technical stuff about watts, amps, and volts. And you don’t need to understand that technical stuff; that’s why we call electricians for help. You just want your table saw to work when you need it and to work well and efficiently, and not trip amp breakers or fuses.
But you now know the right questions to ask and some important considerations for a table saw purchase, the number of circuits your shop may need, the use of extension cords, and a bit more.