[credmond311]

I am buying a table saw that will run best on a 220 outlet. I will eventually wire my shop with a 220 outlet, but that has to wait for now. In the meantime, I wanted to use the dryer's 220 receptacle which is conveniently right next to the garage.

The table saw has a 220 volt NEMA 6-15 plug, and the dryer receptacle is NEMA 10-30R. I found an adapter at home depot here that seems like it will work. I also read that "the cross-compatible NEMA 6-20R can accept a 6-15 or 6-20 plug".

The reps at the company that sells the table saw say it's okay to use an adapter. I like to trust but verify, so thought it was worth a post to see if anyone has experience with this kind of thing and can confirm there is no potential to damage the saw or outlet.

Thanks,
Chris

 

[AllanJ]

It will work but you should not use it. The table saw, intended for a 15 amp circuit, should not be connected to the 30 amp dryer circuit without a breaker for 15 amps in between.

Every appliance, tool, electronic item, even light, has a maximum ampere circuit rating. If this is exceeded then there are a very small number of obscure abnormal circumstances where a fire may occur with, say, 30 amps flowing that would not have occured with much less current flowing.

(The saw will not draw 30 amps simply because the amps are there. Barring a malfunction it will draw just what it needs.)

 

[brric]

It will work but you should not use it. The table saw, intended for a 15 amp circuit, should not be connected to the 30 amp dryer circuit without a breaker for 15 amps in between.

Every appliance, tool, electronic item, even light, has a maximum ampere circuit rating. If this is exceeded then there are a very small number of obscure abnormal circumstances where a fire may occur with, say, 30 amps flowing that would not have occured with much less current flowing.

(The saw will not draw 30 amps simply because the amps are there. Barring a malfunction it will draw just what it needs.)

So, you can not plug a 2 amp lamp into a 20 amp circuit, or a 15 amp table saw into a 20 amp circuit? I call BS.

 

[fotostat]

It will work but you should not use it. The table saw, intended for a 15 amp circuit, should not be connected to the 30 amp dryer circuit without a breaker for 15 amps in between.

Every appliance, tool, electronic item, even light, has a maximum ampere circuit rating. If this is exceeded then there are a very small number of obscure abnormal circumstances where a fire may occur with, say, 30 amps flowing that would not have occured with much less current flowing.

(The saw will not draw 30 amps simply because the amps are there. Barring a malfunction it will draw just what it needs.)

This is the problem with a DIY forum, you have DIYers giving garbage advice like this instead of Pro's. DIYers should only be allowed to ask questions, not answer them.

Shut up and don't post in the electrical section again.

 

[seharper]

The following post is opinion. Some people on this board hate all opinion. Your best way to resolve this is to not read this posting. Reading it anyway then being unhappy is not a good plan.

I am buying a table saw that will run best on a 220 outlet. I will eventually wire my shop with a 220 outlet, but that has to wait for now. In the meantime, I wanted to use the dryer's 220 receptacle which is conveniently right next to the garage.

The table saw has a 220 volt NEMA 6-15 plug, and the dryer receptacle is NEMA 10-30R.

*screech* whirr crunch. That ain't good!

FACT: The NEMA 10-30R is an obsolete type of receptacle that does not have a ground wire. It has a neutral wire instead.

FACT: Manufacturers got a special exception cut into NEC that allows NEMA 10-type receptacles to be used for decades after everything else required grounds. Further, they got an exception to allow "grounding" the appliance by attaching it to neutral. The problem is, if the neutral wire comes loose, the appliance chassis is then electrified, and can kill people.

(opinion) And has. This is a very bad way to hook up *even a dryer*, because this exception was ill-conceived. The logic of the appliance makers is "that's not likely to happen, because dryer receptacles are very rarely disturbed." Also, NEMA 6/10/14-30 are not made for frequent interchange (L6/L14 are). Now, what are you about to start doing?

Your best play is to change that receptacle out to a NEMA 14-30 after either

a) discovering there actually is a ground wire or grounded metal conduit there after all,
b) retrofitting a ground wire, or
c) skipping the ground and going with a GFCI breaker. This requires labeling the 14-30 "GFCI Protected/No Equipment Ground".

This is something you should do regardless, for your family's safety. As part of this you would remove the neutral-ground jumper from the dryer, so ground goes to ground and not neutral. (most especially important with the GFCI option!)

I found an adapter at home depot here that seems like it will work. I also read that "the cross-compatible NEMA 6-20R can accept a 6-15 or 6-20 plug".

Well, things which plug in are outside of NEC's jurisdiction, so it's not a Codevio.

Look for a "UL Listing" on the item. If you find a UL Listing, that means it has been built to UL's safety standards (White Book) and UL has independently confirmed that. Also acceptable is CSA, ETL or any of several other Nationally Recognized Testing Labs (NRTLs), you can google the list of current NRTLs.

CE, CCC, FCC and RoHS are not testing labs.

If UL or other NRTL endorses the adapter, then I cannot say a word to protest.

However here are my concerns:

- Connecting ground to the NEMA 10 neutral. This inherits all the problems that makes NEMA 10 so dangerous, but lacks the mitigating factors. You can cure this by changing to NEMA 14 as discussed above.

- Connecting a 15A load to a 30A breaker. The general problem here is that the 15A load could suffer a serious overload, and the breaker would never even know it, and would just let it burn. Now, UL accounts for that as part of their certification of appliances. Anything that plugs into a 15/20A circuit must be designed so if it has a problem, a 20A breaker will save it. A 30A breaker is not part of the spec and is not tested or certified for.

The reps at the company that sells the table saw say it's okay to use an adapter. I like to trust but verify, so thought it was worth a post to see if anyone has experience with this kind of thing and can confirm there is no potential to damage the saw or outlet.

Did they say "An adapter" or "ALL adapters"? Because SOME adapters would be OK, but not that one again, in my opinion.

If you already have a ground wire or metal conduit back to the panel, one option here is to fit a subpanel here. It can be a $20 cheapie, even. Into this subpanel you fit a 30A for the dryer, and a 15A for this saw. Wow, that was easy.

I can't tell you to retrofit ground to that location and then fit a subpanel, because I don't think you're allowed to do that in one step.

So, you can not plug a 2 amp lamp into a 20 amp circuit, or a 15 amp table saw into a 20 amp circuit? I call BS.

Call UL.

 

[Oso954]

This is the problem with a DIY forum, you have DIYers giving garbage advice like this instead of Pro's. DIYers should only be allowed to ask questions, not answer them.

Shut up and don't post in the electrical section again.

If you want a “pros only“ forum, I’d suggest electrician talk.

This one is called DIY Chatroom.

 

[seharper]

This is the problem with a DIY forum, you have DIYers giving garbage advice like this instead of Pro's.

A logical attack is "NEC 404.2(C) now requires neutrals in switch loops".
An ad-hominem attack is "You're an idiot and your mom is ugly".

Ad-hominem attacks are generally out-of-line.

If you're going to criticize a fellow poster's statements, then you need to be prepared to respond with logic, and that will generally involve clipping out their problematic statement and citing Code to prove why it's incorrect.

The purpose of Code citations for old-timers like yourself is that fellow members are not your apprentice; you can't hold them to the standard of "In 30 years of practice I always did this". Code is what we share.

If your complaint is about signal/noise ratio, try diy.stackexchange.com or other well designed Q&A sites, which have good systems for floating good answers and deterring/deleting rubbish. But it's a Q&A not a chatroom, so there's no rolling discussion. Also courtesy is mandatory.

 

[NCmountainCabin]

...I wanted to use the dryer's 220 receptacle which is conveniently right next to the garage.

The table saw has a 220 volt NEMA 6-15 plug, and the dryer receptacle is NEMA 10-30R. I found an adapter ...

I do the same, and have had no issues and it works great:

I have a NEMA 50amp 14-50 outlet wired to a 50amp double-pole breaker, normally for my 50amp 240v Motorhome

I access this outlet also for two other things - a 30amp 240v dryer, and a 20amp 240v EV charger, both which require an adapter. Both work just fine.

For someone to suggest that just because a device or appliance, which draws LESS amps than the outlet and breaker are designed for, is somehow ineligible to use a 'larger' outlet, is preposterous. It's like saying you can't plug in a 5amp table-side lamp into a 15amp circuit. Or a lamp that only has 'two' wires into a '3 wire' outlet....ridiculous.

Use your adapter and you'll be just fine. When you want to install a 240v outlet and the appropriate dedicated double-pole breaker, do so as you wish.

 

[NCmountainCabin]

I do the same, and have had no issues and it works great:

I have a NEMA 50amp 14-50 outlet wired to a 50amp double-pole breaker, normally for my 50amp 240v Motorhome

I access this outlet also for two other things - a 30amp 240v dryer, and a 20amp 240v EV charger, both which require an adapter. Both work just fine.


For someone to suggest that just because a device or appliance, which draws LESS amps than the outlet and breaker are designed for, is somehow ineligible to use a 'larger' outlet, is preposterous. It's like saying you can't plug in a 5amp table-side lamp into a 15amp circuit. Or a lamp that only has 'two' wires into a '3 wire' outlet....ridiculous.

Use your adapter and you'll be just fine. When you want to install a 240v outlet and the appropriate dedicated double-pole breaker, do so as you wish.

(by the way, they even make a standard 'adapter' to provide a 30amp 120v RV power thru a 50amp 240v outlet, crazy, I know!)

 

[seharper]

Are these connectors UL Listed?

If so, are they listed for a specific/single purpose, like an RV connection?

 

[Let it Snow]

A problem would occur if the 15 amp motor on the table saw lock up. By the time the 30 amp breaker would trip, the motor would be burnt up or on fire.

 

[u2slow]

A problem would occur if the 15 amp motor on the table saw lock up. By the time the 30 amp breaker would trip, the motor would be burnt up or on fire.

Same thing happens with smaller 240V welders. The user manuals cite 20-30A max overcurrent device, yet it comes with a 6-50P cord end. 9 times out of 10, when a generic welding receptacle is installed, its a 50A circuit.


What's the homeowner do with his new welder? Plug it in and go... never giving it another thought.



FWIW, I've 'tapped' the dryer circuit before. (14-30R in that case.) Bring it into a small 2-space subpanel and using a 15-20A 2-pole breaker, wire a smaller 240V receptacle for the table saw. For only slightly more work, add a couple 120V receptacles too.

 

[dmxtothemax]

I would put a small sub panel in the laundry,
Route the 30A line for the dryer thru it
then instal a 15A breaker
And a 15A outlet for the garage.

 

[seharper]

Yup, pretty much. That's the pro/awesomesauce way of doing it, and it's pfft, not even $40.

The only issue I see is you absolutely need ground, and you'd need to retrofit a #10 ground wire back to (somewhere that has #10 or larger going back to the panel).

It's perfectly fine retrofitting ground to the recep today, but there might be a statutory issue with retrofitting ground to a new subpanel. So I would fit it to the recep today, and who can say about tomorrow?

 

[credmond311]

Thanks all for the comments and suggestions.

seharper - I will have to get the dryer receptacle updated per your suggestion. Will need to read further into your three options to understand which to go with.

I am now leaning towards a different table saw (for reasons other than electrical setup) that could still be wired for 220 down the line, but according to the manufacturer will also run fine on 120, but since the tool is 14 amp, a 20 amp circuit would be better. The garage only has a 15 amp receptacle that has also given me trouble running other power tools (garage light on same circuit flicker at startup of tool).

There is a 20 amp circuit that only serves 3 receptacles in a room adjacent to the garage, with the receptacle on the wall separating the room from the garage being the end of the run. So I am now thinking I will just add a 20 amp GFCI outlet to the garage, running it off the end of run receptacle on the other side of the wall.

My father in law is a DIYer and said adding that outlet would be a good way to go. Anyone see any issues with this approach?

If I do decide to go with the original saw, I will definitely revisit the ideas suggested in this thread, so thanks again for your input!

 

[seharper]

Check the breaker and wires on that 15A recep.

There's an exception in Code that allows 15A receptacles on 20A circuits. (both 120V and 240V). Almost all 20A circuits in houses have 15A receps on them, but behind the veil the wire might be #12 and 20A breaker. If so, you can simply swap for a NEMA 5-20, readily available in simplex or the common duplex form-factor.