I have a compressor that runs off 220.
I have a new table saw that I also need to run off 220. Can I pigtail off the one receptacle and run a wire to the table saw ? Both would never be ran at the same time. Do 220 plugs have a way to do this like 110 ?
Barry
Replies
Well, the answer probably depends on your local jurisdiction and how you feel about being code compliant. Most that I know of require dedicated circuits for 240v appliances. There is a potential pitfall to sharing a breaker with multiple tools, since the breaker would have to be sized to the highest demand tool this could leave a lower demand tool vulnerable to being damaged in event of an overload. Say for example you had a planer that required a 240V/30A breaker and a tablesaw that required a 240V/15A breaker both these tools would operate fine on a single 240v/30A breaker assuming the proper wire was used on the entire circuit, in this case 10ga copper, and used one at a time. The problem could be that if the tablesaw ever experienced a 20-25A overload this would not trip the breaker but there is no way of knowing that every component, every wire in the tablesaw could handle this much current with out significant damage and potentially a catastrophic result. A circuit breaker is by design meant to be the weakest link in the circuit to prevent major issues such as wires and switches melting and catching on fire. It is for this reason that many jurisdictions don't permit this type of wiring. Household devices are required to be certified to operate on 120V/20A circuits insuring that they can withstand 20A draws even through they may only need a fraction of that to operate. 240V tools on the other hand are only required to state what their maximum amperage draw could be.
No - you can't safely pigtail off a 220v receptacle (and if anything were to happen, your Homeowners Insurance might reject the Claim). Some options are to unplug and replug each one as needed; run a new 220V outlet; or rewire either to 110v and use an existing outlet.
Thanks ESCH for the detailed explanation. I’ll file this one.
Thanks all
Barry
I have the same situation with my planer, jointer and band saw, all 20 amp. I made up a 12 foot extension cord of 14/3 wire and that has worked for at least 10 years. Keep the male machine end up high, I don't even bend over when I change over.
I know it works for you, but you should know 14ga wire is only rated to handle 15A. Twenty amp circuits require a minimum of 12ga wire and if it was me using it for tools I would opt for 10ga.
First I would suggest contacting a qualified electrician. Where you live and the intended use can affect the answer. While it's true that for household appliances the maximum number of outlets on a circuit may be restricted, I don't know if that applies to a table saw. Where I live at least the washing machine is required to have a dedicated outlet even though it is a 120V 20A circuit. I don't know if table saws and air compressors are necessarily spelled out the same way in building codes, but they may be. As I said, call an electrician who should know the answer in your area.
Secondly, extension cords don't fall under the same rules as household wiring because they are typically short in length and not buried in a wall. Commercially made ones have a maximum current rating so go by that.
The maximum current rating of a piece of wire is related to the voltage, acceptable voltage drop, length, current, insulation type, is it in conduit, solid core or stranded, etc. The 15 and amp rules for household wiring many of us know are based on assumptions including NM sheathed cable and some maximum distance permitted. Unusually long runs may require 12 gauge wire for a 15 amp circuit for example.
Net, call an electrician. It is a complex mix of engineering concerns combined with building codes in your area and sometimes what the local building inspector likes to see.
While I don't disagree with the premise that factors such as length and voltage drop ultimately determine the maximum amperage a wire can handle, that doesn't change the fact that there is no length of cable that allows a 14ga cord made of SOO/SOOW flexible cable to be used on a 20A circuit. If the load were a steady 20A that cord would likely be melted, fortunately for him most tools only get close to the max Amperage at start up, but it still is a bad practice and not one I would encourage other woodworkers to adopt. The difference in cost between 12ga and 14ga cable simply isn't enough to make it worth taking the chance.
Sorry, I wasn't trying to start an argument or tell anyone what extension cord to use. There are online calculators for wire gauge based on voltage/amperage/wire length/voltage drop etc. if anyone cares to find out.
Thanks, esch5995, like some of Ben's videos, you made me look. They are actually 15 amp machines and if I had really been thinking straight I should have realized that. It is a good thing I did look, as when my friend helped me insulate years ago, he ran a second circuit for my table saw and used a 20 amp breaker. Nothing has happened yet, but I'll change that out before my luck runs out.
If you had a 30 year old Unisaws like me, I would tell you not to worry about it they are built like tanks, simple, but tanks. With all the Saw Stops and the related circuitry, imported saws, and bench top saws all bets are off. The manual should tell you the recommended breaker rating if you have it or can find it on line.
Every tool, appliance that pulls more then 15 amps, should be on their own circuit. The cost of running a dedicated circuit, much out ways the cost of replacing your shop or house. Be on the safe side and spend the extra money
Yes you can do it as long as the amp draws are similar, the wiring and breaker are correct sized. Despite what the alarmists say, nothing is going to catch on fire.
Yes, you may have a non-code compliant shop but the reality is it won't be an issue.
I have (4) 220 machines on one circuit. 25 years and the only time a breaker was when one motor went bad.
It's your shop.
Alarmist? Really? As a frequent poster here I think it is my responsibility to make sure I give information that is both helpful and correct especially when there is a potential for bad results. I think it is irresponsible for you or anyone to flat say something can be done without providing all the information the OP or anyone for that matter needs to make an informed decision. I am not a licensed electrician, but my grandfather was and I did study electrical engineering for a couple of years back when gas was still $1 gal and the apple computer was a circuit board on the cover of Byte magazine. I am also a kitchen remodeling professional who deals with electrical codes and inspections daily.
If you read my post I actually said this could be done, although I'm not quite sure what he means by pigtailed, I assume he means multiple outlets on a single breaker. What I pointed out was a very real potential pitfall when using tools on significantly over rated breakers. I think this is only being responsible to provide the OP with all the facts and he can decide what he wants to do.
Giving out electrical advice like this:
"Yes, you may have a non-code compliant shop but the reality is it won't be an issue."
Is simply irresponsible. Do you know how much over current a Saw Stop can handle? Are you going to replace a $500 circuit board for him if it melts because he heeded your advice? What about the majority of tools being made overseas today. Do you really thing they are made to the same standards as your 30 year old tools are?
https://www.reddit.com/r/woodworking/comments/ih47id/ryobi_table_saw_caught_on_fire/
https://www.cbsnews.com/sacramento/news/porter-cable-table-saw-recall/
"It's your shop." yes it is but explain that to the the local building commission and possibly your insurance company if the worst case scenario does occur. I will acknowledge that I live and work in major population center where electrical codes are generally stricter and more diligently enforced and I know some rural communities are more laissez faire regarding code enforcement but it behooves anyone posting here regarding electrical advice to error on the side of caution.
Just my opinion
You might want to dial it back a notch. DRBWWing was not specifically talking to you. He was posting his opinion and is entitled to do so, same as you.
We have pretty restrictive electrical codes here and that wasn't an issue for me. My jointer and table sawnare both converted 220 and are on the same circuit. As you said not ran together. The DC is on it's own circuit because it will be run at the same time. Honestly I have run the ts and jointer at the same time without issue.