Well you've got some information to go on from at least one licensed electrician. I'll add my two cents, if it's not done by a licensed electrician (and you have proof) then if a fire were to occur your insurance company will see that alone as reason enough not to cover any damages.

 

Sometimes I think that people post question like this just to see the arguments and to see how many different ways people can agree and disagree. Am I the only one that thinks the photo of the OP looks like Satan? LOL.

I find it curious that no one has pointed out that the combination receptacle in the diagram in OP is a 15 amp not a 20 amp receptacle as the diagram is labeled. If you are going to do that, you at least need one of these.

BTW, I looked at the installation instructions for the 15 AMP one that is displayed above and it shows one configuration exactly as he described above-a 4 wire, with 2 hot, 1 neutral and a ground. I am not an electrician but presumably that means that means it is not a problem. Whether it is a good idea to run an extension cord to power this receptacle may be another question. Discuss amongst yourselves. ;-)

 

Yeah it can get stupid sometimes but also insightful as well.

 

Those combo receptacles have always seemed like a terrible idea to me. It would be pathetically easy to plug a tool into the wrong outlet and (depending on the tool) damage it.

I've only ever heard of them used where you feed each outlet with a separate circuit.

 

That's why they have different plug prong arrangements for different voltages.

 

Some good replies above, I'm on my phone but will respond to them when I get to the house.

The photo is Atlas, I'm an Ayn Rand fan.

 

Well you ve got some information to go on from at least one licensed electrician. I ll add my two cents, if it s not done by a licensed electrician (and you have proof) then if a fire were to occur your insurance company will see that alone as reason enough not to cover any damages.

- bigblockyeti

Pull a permit for the same reason. That little inspection sticker can be worth its weight in gold.

 

..........
I find it curious that no one has pointed out that the combination receptacle in the diagram in OP is a 15 amp not a 20 amp receptacle as the diagram is labeled. If you are going to do that, you at least need one of these.

- Lazyman

Here we go again with misinformation….. The pass through voltage rating on that outlet is 20A. The blade configuration for the 120V side only allows for a 15A style plug to be inserted. But, on multiple outlet circuits it is code compliant to use 15A outlets on a 20A circuit. You don't need the 120V outlet with the sideways blade because hardly, if any, homeowner equipment uses a true 20A plug.

 

I was only looking at the online specs and it says that the maximum is 15 amps. Does that mean it can handle 20?

Edit: And by pass through I assume you mean where you sort of daisy chain receptacles from one place to another? It doesn't appear to have terminals for doing that so it would seem that pass-through would not be an option here?

 

No.

 

I was just l looking at the online specs and it says that the maximum is 15 amps. Does that mean it can handle 20?

- Lazyman

As Fridge said, no. That outlet can only supply 15A appliances/equipment. The max amp circuit that the outlet can be used on is 20A because it's a duplex. If it was a single (one) outlet on a 20A circuit then the outlet would need to be 20A.

There are side terminals for adding additional outlets and or continuing the circuit.

 

you can hook up table saw like that …..as long as you only cut alder wood LMAO :<))

 

That s why they have different plug prong arrangements for different voltages.

- bigblockyeti

The one in the original post has different prongs, but the one linked in a later post had two identical arrangements.

 

I understand that the plug/prong configuration limits each appliance to 15A, but if he has one 15A labeled duplex receptacle on this circuit (ignoring the whole extension cord thing for the moment), your recommendation is to use a 20A breaker on it?

When I have looked in the past, the recommendation I have seen is that if you have one receptacle, either duplex or single, your breaker should be the same as the labeled rating on that receptacle, not higher. Might be overkill for just one duplex?

 

I understand that the plug/prong configuration limits each appliance to 15A, but if he has one 15A labeled duplex receptacle on this circuit (ignoring the whole extension cord thing for the moment), your recommendation is to use a 20A breaker on it?

When I have looked in the past, the recommendation I have seen is that if you have one receptacle, either duplex or single, your breaker should be the same as the labeled rating on that receptacle, not higher. Might be overkill for just one duplex?

- Lazyman

It's best to have outlet circuits be 20A, but you only need to use 15A outlets when using a duplex receptacle. A duplex is considered as two outlets. The NEC allows 15A duplex outlets on a 20A circuit. When it's a single outlet (not duplex) the outlet has to be rated the same as the circuit. For single receptacle see NEC 210.21(B)(1), for multiple receptacles see NEC 210,21(B)(3).

 

The one in the original post has different prongs, but the one linked in a later post had two identical arrangements.

- jonah

Similar, not identical.

 

I've found multiple conversations about this topic and they all essentially mimic this thread, half a dozen saying it's "ok but not advisable", a handful of people saying that it's good to go and they have either installed circuits like this in the past for clients or have them installed at their shop with no issues for "years".

and half a dozen size arguments as to whether the links are correct, LOL.

the only real issue that I see is my concept of using a "locking plug" to extend the 120v/240v circuit to the mobile table saw station (I would use 30A plug/outlet for that connection and plan on 10/3 wire for my extension cord).

I have access to commercial master electricians as I've been a general contractor for about 20 years. I'll talk with one of them about it on monday.

On a side note, my panel has 40A and 30A circuits that are effectively not used (Electric Range and Dryer but our house is all gas), so I will probably just abandon the house wiring and run my circuit off one of these spaces in the panel.
-which should eliminate all the "breaker" side arguments in this thread..

 

Thanks for the info. Now consider the rest of his scenario. He wants to run this duplex outlet at the end of an extension cord presumably plugged into a single 20A 220v receptacle. He also wants to eventually plug both the 9.3A table saw and a 3.5A 220V (or 7A 110v if he wants to use the same receptacle?) dust collector into this setup. Is he still good, including with motor surges for startup, etc.? He didn't say how long or what gauge the extension cord would be. I assume that would make a difference if the length was fairly long.

Also, 2005 NEC 210.21(B)(1) says the maximum load for a cord and plug connected load on a 15A rated receptacle is 12A. Is that the 80% rule? Does that apply here and does that mean that his 9.2A + 3.5A (12.7A) saw/DC combination would require a 20A receptacle which has a maximum load of 16A?

 

Thanks for the info. Now consider the rest of his scenario. He wants to run this duplex outlet at the end of an extension cord presumably plugged into a single 20A 220v receptacle. He also wants to eventually plug both the 9.3A table saw and a 3.5A 220V (or 7A 110v if he wants to use the same receptacle?) dust collector into this setup. Is he still good, including with motor surges for startup, etc.? He didn t say how long or what gauge the extension cord would be. I assume that would make a difference if the length was fairly long.

Also, 2005 NEC 210.21(B)(1) says the maximum load for a cord and plug connected load on a 15A rated receptacle is 12A. Is that the 80% rule? Does that apply here and does that mean that his 9.2A + 3.5A (12.7A) saw/DC combination would require a 20A receptacle which has a maximum load of 16A?

- Lazyman

this post is accurate as to my intentions, however, I will not use any 15A receptacles, everything on the 120v side will be 20A and 20A on the 240v side as well.
Although, the more i think about it, I'll probably just wire a double gang box (off the extension cord, at the TS station) and use a single flat spade 20A outlet for the table saw and a standard, commercial grade 20A outlet for the router. If I go this route, I wont need to wire the dust collection into the same circuit (which technically, I shouldn't do anyway).

I looked into a 70A subpanel, but I'm just not interested in spending that kind of money (over $100 when i stopped counting) and it was actually limited to 2 spaces/4 tandem circuits. I just dont have the need with the 3ea 20A circuits run to the shop now.

 

Thanks for the info. Now consider the rest of his scenario. He wants to run this duplex outlet at the end of an extension cord presumably plugged into a single 20A 220v receptacle. He also wants to eventually plug both the 9.3A table saw and a 3.5A 220V (or 7A 110v if he wants to use the same receptacle?) dust collector into this setup. Is he still good, including with motor surges for startup, etc.? He didn t say how long or what gauge the extension cord would be. I assume that would make a difference if the length was fairly long.

Also, 2005 NEC 210.21(B)(1) says the maximum load for a cord and plug connected load on a 15A rated receptacle is 12A. Is that the 80% rule? Does that apply here and does that mean that his 9.2A + 3.5A (12.7A) saw/DC combination would require a 20A receptacle which has a maximum load of 16A?

- Lazyman

Yep.

 

I looked into a 70A subpanel, but I m just not interested in spending that kind of money (over $100 when i stopped counting) and it was actually limited to 2 spaces/4 tandem circuits. I just dont have the need with the 3ea 20A circuits run to the shop now.

- rbrjr1

Check out this 20 space 100 amp panel that comes with 5 breakers for under $60.

https://www.homedepot.com/p/GE-PowerMark-Gold-100-Amp-20-Space-20-Circuit-Indoor-Main-Breaker-Value-Kit-TM2010CCU2K/100115205

 

Check out this 20 space 100 amp panel that comes with 5 breakers for under $60.
https://www.homedepot.com/p/GE-PowerMark-Gold-100-Amp-20-Space-20-Circuit-Indoor-Main-Breaker-Value-Kit-TM2010CCU2K/100115205
- Roy Turbett

subpanel is the cheap part, the feeder and sub breaker in the main panel would be another $120 (wire alone will cost over $80)
plus, Ive already got a full panel with the majority of the spaces being 1/2" breakers. Im not sure I could pull another 100A off the panel.

this way, all I will spend is the $60 for the 10/3 and $20 for a new double pole 20A breaker.

 

update.. lol

in 2018 we renovated and I ended up using the extra "earmarked" spaces in the panel for the renovation. I dropped a 70A subpanel in using the "electric range" circuit space in my original panel. When the subpanel was added, I ran some shop circuits from it (removing their home runs from the house panel). NOW, I'm looking to finalize this work before spring of upgrading the wiring in the shop.

[controversy re-introduced lol ]
In researching the receptacle, I also have found that the dual voltage (20A) outlet I anticipate having in the table saw station CAN BE fed from two different circuits. The receptacle provides for the separation of it's 120v feed and it's 240v feed to actually have two separate originating circuits (OR to pull from the same 240v wiring). The 240v circuit will come from a multi-wire branch circuit feeding other 240v machines, and the 120v circuit will come from a 120v circuit feeding other 120v machines. I will run two extension cords to the saw station which have been taped/shrinktubed together..